repo_zf1/documentation/manual/en/module_specs/Zend_View-Helpers-Navigation.xml

<?xml version="1.0" encoding="UTF-8"?>
<!-- Reviewed: no -->
<sect3 id="zend.view.helpers.initial.navigation">
    <title>Navigation Helpers</title>

    <para>
        The navigation helpers are used for rendering navigational elements
        from <link linkend="zend.navigation.containers">Zend_Navigation_Container</link>
        instances.
    </para>

    <para>
        There are 5 built-in helpers:
    </para>

    <itemizedlist>
        <listitem>
            <para>
                <link
                    linkend="zend.view.helpers.initial.navigation.breadcrumbs">Breadcrumbs</link>,
                used for rendering the path to the currently active page.
            </para>
        </listitem>
        <listitem>
            <para>
                <link linkend="zend.view.helpers.initial.navigation.links">Links</link>,
                used for rendering navigational head links (e.g.
                <code>&lt;link rel="next" href="..." /&gt;</code>)
            </para>
        </listitem>
        <listitem>
            <para>
                <link linkend="zend.view.helpers.initial.navigation.menu">Menu</link>,
                used for rendering menus.
            </para>
        </listitem>
        <listitem>
            <para>
                <link linkend="zend.view.helpers.initial.navigation.sitemap">Sitemap</link>,
                used for rendering sitemaps conforming to the
                <ulink url="http://www.sitemaps.org/protocol.php">Sitemaps <acronym>XML</acronym> format</ulink>.
            </para>
        </listitem>
        <listitem>
            <para>
                <link
                    linkend="zend.view.helpers.initial.navigation.navigation">Navigation</link>,
                used for proxying calls to other navigational helpers.
            </para>
        </listitem>
    </itemizedlist>

    <para>
        All built-in helpers extend
        <classname>Zend_View_Helper_Navigation_HelperAbstract</classname>, which
        adds integration with <link linkend="zend.acl">ACL</link> and
        <link linkend="zend.translate">translation</link>. The abstract class
        implements the interface
        <classname>Zend_View_Helper_Navigation_Helper</classname>, which
        defines the following methods:
    </para>

    <itemizedlist>
        <listitem>
            <para>
                <code>{get|set}Container()</code> gets/sets the navigation
                container the helper should operate on by default, and
                <methodname>hasContainer()</methodname> checks if the helper
                has container registered.
            </para>
        </listitem>
        <listitem>
            <para>
                <code>{get|set}Translator()</code> gets/sets the
                translator used for translating labels and titles, and
                <code>{get|set}UseTranslator()</code> controls whether
                the translator should be enabled. The method
                <methodname>hasTranslator()</methodname> checks if the helper has
                a translator registered.
            </para>
        </listitem>
        <listitem>
            <para>
                <code>{get|set}Acl()</code>, <code>{get|set}Role()</code>,
                gets/sets <acronym>ACL</acronym> (<classname>Zend_Acl</classname>) instance and
                role (<type>String</type> or
                <classname>Zend_Acl_Role_Interface</classname>) used for
                filtering out pages when rendering, and
                <code>{get|set}UseAcl()</code> controls whether <acronym>ACL</acronym> should
                be enabled. The methods <methodname>hasAcl()</methodname> and
                <methodname>hasRole()</methodname> checks if the helper has an <acronym>ACL</acronym>
                instance or a role registered.
            </para>
        </listitem>
        <listitem>
            <para>
                <methodname>__toString()</methodname>, magic method to ensure that
                helpers can be rendered by <code>echo</code>ing the
                helper instance directly.
            </para>
        </listitem>
        <listitem>
            <para>
                <methodname>render()</methodname>, must be implemented by concrete
                helpers to do the actual rendering.
            </para>
        </listitem>
     </itemizedlist>

    <para>
         In addition to the method stubs from the interface, the abstract
         class also implements the following methods:
    </para>

     <itemizedlist>
        <listitem>
            <para>
                <code>{get|set}Indent()</code> gets/set indentation. The
                setter accepts a <type>String</type> or an <code>int</code>.
                In the case of an <code>int</code>, the helper will use
                the given number of spaces for indentation. I.e.,
                <methodname>setIndent(4)</methodname> means 4 initial spaces of
                indentation. Indentation can be specified for all helpers
                except the Sitemap helper.
            </para>
        </listitem>
        <listitem>
            <para>
                <code>{get|set}MinDepth()</code> gets/set the minimum depth
                a page must have to be included by the helper. Setting
                <constant>NULL</constant> means no minimum depth.
            </para>
        </listitem>
        <listitem>
            <para>
                <code>{get|set}MaxDepth()</code> gets/set the maximum depth
                a page can have to be included by the helper. Setting
                <constant>NULL</constant> means no maximum depth.
            </para>
        </listitem>
        <listitem>
            <para>
                <code>{get|set}RenderInvisible()</code> gets/set whether to
                render items that have been marked as invisible or not.
            </para>
        </listitem>
        <listitem>
            <para>
                <methodname>__call()</methodname> is used for proxying calls to the
                container registered in the helper, which means you can
                call methods on a helper as if it was a container. See <link
                    linkend="zend.view.helpers.initial.navigation.proxy.example">example</link>
                below.
            </para>
        </listitem>
        <listitem>
            <para>
                <methodname>findActive($container, $minDepth, $maxDepth)</methodname>
                is used for finding the deepest active page in the given
                container. If depths are not given, the method will use
                the values retrieved from <methodname>getMinDepth()</methodname> and
                <methodname>getMaxDepth()</methodname>. The deepest active page must
                be between <varname>$minDepth</varname> and <varname>$maxDepth</varname>
                inclusively. Returns an array containing a reference to the
                found page instance and the depth at which the page was
                found.
            </para>
        </listitem>
        <listitem>
            <para>
                <methodname>htmlify()</methodname> renders an <code>a</code> HTML
                element from a <classname>Zend_Navigation_Page</classname>
                instance.
            </para>
        </listitem>
        <listitem>
            <para>
                <methodname>accept()</methodname> is used for determining if a page
                should be accepted when iterating containers. This method
                checks for page visibility and verifies that the helper's
                role is allowed access to the page's resource/privilege.
            </para>
        </listitem>
        <listitem>
            <para>
                <code>static setDefaultAcl()</code> is used for setting
                a defualt <acronym>ACL</acronym> object that will be used by helpers.
            </para>
        </listitem>
        <listitem>
            <para>
                <code>static setDefaultRole()</code> is used for setting
                a default <acronym>ACL</acronym> that will be used by helpers
            </para>
        </listitem>
    </itemizedlist>

    <para>
        If a navigation container is not explicitly set in a helper using
        <code>$helper->setContainer($nav)</code>, the helper will look
        for a container instance with the key <classname>Zend_Navigation</classname> in
        <link linkend="zend.registry">the registry</link>.
        If a container is not explicitly set or found in the registry, the
        helper will create an empty <classname>Zend_Navigation</classname>
        container when calling <code>$helper->getContainer()</code>.
    </para>

    <example id="zend.view.helpers.initial.navigation.proxy.example">
        <title>Proxying calls to the navigation container</title>

        <para>
            Navigation view helpers use the magic method <methodname>__call()</methodname>
            to proxy method calls to the navigation container that is
            registered in the view helper.
        </para>

        <programlisting language="php"><![CDATA[
$this->navigation()->addPage(array(
    'type' => 'uri',
    'label' => 'New page'));
]]></programlisting>

        <para>
            The call above will add a page to the container in the
            <classname>Navigation</classname> helper.
        </para>
    </example>

    <sect4 id="zend.view.helpers.initial.navigation.i18n">
        <title>Translation of labels and titles</title>

        <para>
            The navigation helpers support translation of page labels and titles.
            You can set a translator of type <classname>Zend_Translate</classname>
            or <classname>Zend_Translate_Adapter</classname> in the helper using
            <code>$helper->setTranslator($translator)</code>, or like with other
            I18n-enabled components; by adding the translator to
            <link linkend="zend.registry">the registry</link> by using the key
            <classname>Zend_Translate</classname>.
        </para>

        <para>
            If you want to disable translation, use <code>$helper->setUseTranslator(false)</code>.
        </para>

        <para>
            The
            <link linkend="zend.view.helpers.initial.navigation.navigation">proxy
            helper</link> will inject its own translator to the helper it
            proxies to if the proxied helper doesn't already have a translator.
        </para>

        <note>
            <para>
                There is no translation in the sitemap helper, since there
                are no page labels or titles involved in an <acronym>XML</acronym> sitemap.
            </para>
        </note>
    </sect4>

    <sect4 id="zend.view.helpers.initial.navigation.acl">
        <title>Integration with ACL</title>

        <para>
            All navigational view helpers support <acronym>ACL</acronym> inherently from the
            class <classname>Zend_View_Helper_Navigation_HelperAbstract</classname>.
            A <classname>Zend_Acl</classname> object can be assigned to
            a helper instance with <code>$helper->setAcl($acl)</code>, and role
            with <code>$helper->setRole('member')</code> or
            <code>$helper->setRole(new Zend_Acl_Role('member'))</code> . If <acronym>ACL</acronym>
            is used in the helper, the role in the helper must be allowed by
            the <acronym>ACL</acronym> to access a page's <code>resource</code> and/or have the
            page's <code>privilege</code> for the page to be included when
            rendering.
        </para>

        <para>
            If a page is not accepted by <acronym>ACL</acronym>, any descendant page will also
            be excluded from rendering.
        </para>

        <para>
            The
            <link linkend="zend.view.helpers.initial.navigation.navigation">proxy
            helper</link> will inject its own <acronym>ACL</acronym> and role to the helper it
            proxies to if the proxied helper doesn't already have any.
        </para>

        <para>
            The examples below all show how <acronym>ACL</acronym> affects rendering.
        </para>
    </sect4>

    <sect4 id="zend.view.helpers.initial.navigation.setup">
        <title>Navigation setup used in examples</title>

        <para>
            This example shows the setup of a navigation container for a
            fictional software company.
        </para>

        <para>
            Notes on the setup:
        </para>

        <itemizedlist>
            <listitem>
                <para>
                    The domain for the site is <code>www.example.com</code>.
                </para>
            </listitem>
            <listitem>
                <para>
                    Interesting page properties are marked with a comment.
                </para>
            </listitem>
            <listitem>
                <para>
                    Unless otherwise is stated in other examples, the user
                    is requesting the <acronym>URL</acronym>
                    <code>http://www.example.com/products/server/faq/</code>,
                    which translates to the page labeled <constant>FAQ</constant>
                    under <code>Foo Server</code>.
                </para>
            </listitem>
            <listitem>
                <para>
                    The assumed <acronym>ACL</acronym> and router setup is shown below the
                    container setup.
                </para>
            </listitem>
        </itemizedlist>

        <programlisting language="php"><![CDATA[
/*
 * Navigation container (config/array)

 * Each element in the array will be passed to
 * Zend_Navigation_Page::factory() when constructing
 * the navigation container below.
 */
$pages = array(
    array(
        'label'      => 'Home',
        'title'      => 'Go Home',
        'module'     => 'default',
        'controller' => 'index',
        'action'     => 'index',
        'order'      => -100 // make sure home is the first page
    ),
    array(
        'label'      => 'Special offer this week only!',
        'module'     => 'store',
        'controller' => 'offer',
        'action'     => 'amazing',
        'visible'    => false // not visible
    ),
    array(
        'label'      => 'Products',
        'module'     => 'products',
        'controller' => 'index',
        'action'     => 'index',
        'pages'      => array(
            array(
                'label'      => 'Foo Server',
                'module'     => 'products',
                'controller' => 'server',
                'action'     => 'index',
                'pages'      => array(
                    array(
                        'label'      => 'FAQ',
                        'module'     => 'products',
                        'controller' => 'server',
                        'action'     => 'faq',
                        'rel'        => array(
                            'canonical' => 'http://www.example.com/?page=faq',
                            'alternate' => array(
                                'module'     => 'products',
                                'controller' => 'server',
                                'action'     => 'faq',
                                'params'     => array('format' => 'xml')
                            )
                        )
                    ),
                    array(
                        'label'      => 'Editions',
                        'module'     => 'products',
                        'controller' => 'server',
                        'action'     => 'editions'
                    ),
                    array(
                        'label'      => 'System Requirements',
                        'module'     => 'products',
                        'controller' => 'server',
                        'action'     => 'requirements'
                    )
                )
            ),
            array(
                'label'      => 'Foo Studio',
                'module'     => 'products',
                'controller' => 'studio',
                'action'     => 'index',
                'pages'      => array(
                    array(
                        'label'      => 'Customer Stories',
                        'module'     => 'products',
                        'controller' => 'studio',
                        'action'     => 'customers'
                    ),
                    array(
                        'label'      => 'Support',
                        'module'     => 'prodcts',
                        'controller' => 'studio',
                        'action'     => 'support'
                    )
                )
            )
        )
    ),
    array(
        'label'      => 'Company',
        'title'      => 'About us',
        'module'     => 'company',
        'controller' => 'about',
        'action'     => 'index',
        'pages'      => array(
            array(
                'label'      => 'Investor Relations',
                'module'     => 'company',
                'controller' => 'about',
                'action'     => 'investors'
            ),
            array(
                'label'      => 'News',
                'class'      => 'rss', // class
                'module'     => 'company',
                'controller' => 'news',
                'action'     => 'index',
                'pages'      => array(
                    array(
                        'label'      => 'Press Releases',
                        'module'     => 'company',
                        'controller' => 'news',
                        'action'     => 'press'
                    ),
                    array(
                        'label'      => 'Archive',
                        'route'      => 'archive', // route
                        'module'     => 'company',
                        'controller' => 'news',
                        'action'     => 'archive'
                    )
                )
            )
        )
    ),
    array(
        'label'      => 'Community',
        'module'     => 'community',
        'controller' => 'index',
        'action'     => 'index',
        'pages'      => array(
            array(
                'label'      => 'My Account',
                'module'     => 'community',
                'controller' => 'account',
                'action'     => 'index',
                'resource'   => 'mvc:community.account' // resource
            ),
            array(
                'label' => 'Forums',
                'uri'   => 'http://forums.example.com/',
                'class' => 'external' // class
            )
        )
    ),
    array(
        'label'      => 'Administration',
        'module'     => 'admin',
        'controller' => 'index',
        'action'     => 'index',
        'resource'   => 'mvc:admin', // resource
        'pages'      => array(
            array(
                'label'      => 'Write new article',
                'module'     => 'admin',
                'controller' => 'post',
                'aciton'     => 'write'
            )
        )
    )
);

// Create container from array
$container = new Zend_Navigation($pages);

// Store the container in the proxy helper:
$view->getHelper('navigation')->setContainer($container);

// ...or simply:
$view->navigation($container);

// ...or store it in the reigstry:
Zend_Registry::set('Zend_Navigation', $container);
]]></programlisting>

        <para>
            In addition to the container above, the following setup is assumed:
        </para>

        <programlisting language="php"><![CDATA[
// Setup router (default routes and 'archive' route):
$front = Zend_Controller_Front::getInstance();
$router = $front->getRouter();
$router->addDefaultRoutes();
$router->addRoute(
    'archive',
    new Zend_Controller_Router_Route(
        '/archive/:year',
        array(
            'module'     => 'company',
            'controller' => 'news',
            'action'     => 'archive',
            'year'       => (int) date('Y') - 1
        ),
        array('year' => '\d+')
    )
);

// Setup ACL:
$acl = new Zend_Acl();
$acl->addRole(new Zend_Acl_Role('member'));
$acl->addRole(new Zend_Acl_Role('admin'));
$acl->add(new Zend_Acl_Resource('mvc:admin'));
$acl->add(new Zend_Acl_Resource('mvc:community.account'));
$acl->allow('member', 'mvc:community.account');
$acl->allow('admin', null);

// Store ACL and role in the proxy helper:
$view->navigation()->setAcl($acl)->setRole('member');

// ...or set default ACL and role statically:
Zend_View_Helper_Navigation_HelperAbstract::setDefaultAcl($acl);
Zend_View_Helper_Navigation_HelperAbstract::setDefaultRole('member');
]]></programlisting>
    </sect4>

    <sect4 id="zend.view.helpers.initial.navigation.breadcrumbs">
        <title>Breadcrumbs Helper</title>

        <para>
            Breadcrumbs are used for indicating where in a sitemap
            a user is currently browsing, and are typically rendered
            like this: "You are here: Home > Products > FantasticProduct 1.0".
            The breadcrumbs helper follows the guidelines from <ulink
                url="http://developer.yahoo.com/ypatterns/pattern.php?pattern=breadcrumbs">Breadcrumbs
                Pattern - Yahoo! Design Pattern Library</ulink>,
            and allows simple customization (minimum/maximum depth, indentation,
            separator, and whether the last element should be linked), or
            rendering using a partial view script.
        </para>

        <para>
            The Breadcrumbs helper works like this; it finds the deepest active
            page in a navigation container, and renders an upwards path to
            the root. For <acronym>MVC</acronym> pages, the "activeness" of a page is
            determined by inspecting the request object, as stated in the
            section on <link linkend="zend.navigation.pages.mvc">Zend_Navigation_Page_Mvc</link>.
        </para>

        <para>
            The helper sets the <code>minDepth</code> property to 1 by default,
            meaning breadcrumbs will not be rendered if the deepest active page
            is a root page. If <code>maxDepth</code> is specified, the helper
            will stop rendering when at the specified depth (e.g. stop at level
            2 even if the deepest active page is on level 3).
        </para>

        <para>
            Methods in the breadcrumbs helper:
        </para>

        <itemizedlist>
           <listitem>
               <para>
                   <code>{get|set}Separator()</code> gets/sets separator
                   string that is used between breadcrumbs. Defualt is
                   <code>' &amp;gt; '</code>.
               </para>
           </listitem>
           <listitem>
               <para>
                   <code>{get|set}LinkLast()</code> gets/sets whether the
                   last breadcrumb should be rendered as an anchor or not.
                   Default is <constant>FALSE</constant>.
               </para>
           </listitem>
           <listitem>
               <para>
                   <code>{get|set}Partial()</code> gets/sets a partial view
                   script that should be used for rendering breadcrumbs.
                   If a partial view script is set, the helper's
                   <methodname>render()</methodname> method will use the
                   <methodname>renderPartial()</methodname> method. If no partial is
                   set, the <methodname>renderStraight()</methodname> method is used.
                   The helper expects the partial to be a <type>String</type>
                   or an <type>Array</type> with two elements. If the partial
                   is a <type>String</type>, it denotes the name of the partial
                   script to use. If it is an <type>Array</type>, the first
                   element will be used as the name of the partial view
                   script, and the second element is the module where the
                   script is found.
               </para>
           </listitem>
           <listitem>
               <para>
                   <methodname>renderStraight()</methodname> is the default render
                   method.
               </para>
           </listitem>
           <listitem>
               <para>
                   <methodname>renderPartial()</methodname> is used for rendering
                   using a partial view script.
               </para>
           </listitem>
       </itemizedlist>

        <example id="zend.view.helpers.initial.navigation.breadcrumbs.example1">
            <title>Rendering breadcrumbs</title>

            <para>
                This example shows how to render breadcrumbs with default
                settings.
            </para>

            <programlisting language="php"><![CDATA[
In a view script or layout:
<?php echo $this->navigation()->breadcrumbs(); ?>

The two calls above take advantage of the magic __toString() method,
and are equivalent to:
<?php echo $this->navigation()->breadcrumbs()->render(); ?>

Output:
<a href="/products">Products</a> &gt; <a href="/products/server">Foo Server</a> &gt; FAQ
]]></programlisting>
        </example>

        <example id="zend.view.helpers.initial.navigation.breadcrumbs.example2">
            <title>Specifying indentation</title>

            <para>
                This example shows how to render breadcrumbs with initial
                indentation.
            </para>

            <programlisting language="php"><![CDATA[
Rendering with 8 spaces indentation:
<?php echo $this->navigation()->breadcrumbs()->setIndent(8);?>

Output:
        <a href="/products">Products</a> &gt; <a href="/products/server">Foo Server</a> &gt; FAQ
]]></programlisting>
        </example>

        <example id="zend.view.helpers.initial.navigation.breadcrumbs.example3">
            <title>Customize breadcrumbs output</title>

            <para>
                This example shows how to customze breadcrumbs output by
                specifying various options.
            </para>

            <programlisting language="php"><![CDATA[
In a view script or layout:

<?php
echo $this->navigation()
          ->breadcrumbs()
          ->setLinkLast(true)                   // link last page
          ->setMaxDepth(1)                      // stop at level 1
          ->setSeparator(' &#9654;' . PHP_EOL); // cool separator with newline
?>

Output:
<a href="/products">Products</a> &#9654;
<a href="/products/server">Foo Server</a>

/////////////////////////////////////////////////////

Setting minimum depth required to render breadcrumbs:

<?php
$this->navigation()->breadcrumbs()->setMinDepth(10);
echo $this->navigation()->breadcrumbs();
?>

Output:
Nothing, because the deepest active page is not at level 10 or deeper.
]]></programlisting>
        </example>

        <example id="zend.view.helpers.initial.navigation.breadcrumbs.example4">
            <title>Rendering breadcrumbs using a partial view script</title>

            <para>
                This example shows how to render customized breadcrumbs using
                a partial vew script. By calling <methodname>setPartial()</methodname>,
                you can specify a partial view script that will be used
                when calling <methodname>render()</methodname>. When a partial is specified,
                the <methodname>renderPartial()</methodname> method will be called. This
                method will find the deepest active page and pass an array
                of pages that leads to the active page to the partial view
                script.
            </para>

            <para>
                In a layout:
            </para>

            <programlisting language="php"><![CDATA[
$partial = ;
echo $this->navigation()->breadcrumbs()
                        ->setPartial(array('breadcrumbs.phtml', 'default'));
]]></programlisting>

            <para>
                Contents of
                <code>application/modules/default/views/breadcrumbs.phtml</code>:
            </para>

            <programlisting language="php"><![CDATA[
echo implode(', ', array_map(
        create_function('$a', 'return $a->getLabel();'),
        $this->pages));
]]></programlisting>

            <para>
                Output:
            </para>

            <programlisting language="php"><![CDATA[
Products, Foo Server, FAQ
]]></programlisting>
        </example>
    </sect4>

    <sect4 id="zend.view.helpers.initial.navigation.links">
        <title>Links Helper</title>

        <para>
            The links helper is used for rendering HTML <constant>LINK</constant>
            elements. Links are used for describing document relationships
            of the currently active page. Read more about links and link
            types at <ulink url="http://www.w3.org/TR/html4/struct/links.html#h-12.3">Document
                relationships: the LINK element (HTML4 W3C Rec.)</ulink>
            and <ulink
                url="http://www.w3.org/TR/html4/types.html#h-6.12">Link types (HTML4 W3C
                Rec.)</ulink> in the HTML4 W3C Recommendation.
        </para>

        <para>
            There are two types of relations; forward and reverse, indicated
            by the keyords <code>'rel'</code> and <code>'rev'</code>. Most
            methods in the helper will take a <varname>$rel</varname> param, which
            must be either <code>'rel'</code> or <code>'rev'</code>. Most
            methods also take a <varname>$type</varname> param, which is used
            for specifying the link type (e.g. alternate, start, next, prev,
            chapter, etc).
        </para>

        <para>
            Relationships can be added to page objects manually, or found
            by traversing the container registered in the helper. The method
            <methodname>findRelation($page, $rel, $type)</methodname> will first try
            to find the given <varname>$rel</varname> of <varname>$type</varname> from
            the <varname>$page</varname> by calling <code>$page->findRel($type)</code>
            or <code>$page->findRel($type)</code>. If the <varname>$page</varname>
            has a relation that can be converted to a page instance, that
            relation will be used. If the <varname>$page</varname> instance doesn't
            have the specified <varname>$type</varname>, the helper will look for
            a method in the helper named <code>search$rel$type</code> (e.g.
            <methodname>searchRelNext()</methodname> or
            <methodname>searchRevAlternate()</methodname>).
            If such a method exists, it will be used for determining the
            <varname>$page</varname>'s relation by traversing the container.
        </para>

        <para>
            Not all relations can be determined by traversing the container.
            These are the relations that will be found by searching:
        </para>

        <itemizedlist>
            <listitem>
                <para>
                    <methodname>searchRelStart()</methodname>, forward 'start'
                    relation: the first page in the container.
                </para>
            </listitem>
            <listitem>
                <para>
                    <methodname>searchRelNext()</methodname>, forward 'next'
                    relation; finds the next page in the container, i.e.
                    the page after the active page.
                </para>
            </listitem>
            <listitem>
                <para>
                    <methodname>searchRelPrev()</methodname>, forward 'prev'
                    relation; finds the previous page, i.e. the page before
                    the active page.
                </para>
            </listitem>
            <listitem>
                <para>
                    <methodname>searchRelChapter()</methodname>, forward 'chapter'
                    relations; finds all pages on level 0 except the 'start'
                    relation or the active page if it's on level 0.
                </para>
            </listitem>
            <listitem>
                <para>
                    <methodname>searchRelSection()</methodname>, forward 'section'
                    relations; finds all child pages of the active page if
                    the active page is on level 0 (a 'chapter').
                </para>
            </listitem>
            <listitem>
                <para>
                    <methodname>searchRelSubsection()</methodname>, forward 'subsection'
                    relations; finds all child pages of the active page if
                    the active pages is on level 1 (a 'section').
                </para>
            </listitem>
            <listitem>
                <para>
                    <methodname>searchRevSection()</methodname>, reverse 'section'
                    relation; finds the parent of the active page if the
                    active page is on level 1 (a 'section').
                </para>
            </listitem>
            <listitem>
                <para>
                    <methodname>searchRevSubsection()</methodname>, reverse 'subsection'
                    relation; finds the parent of the active page if the
                    active page is on level 2 (a 'subsection').
                </para>
            </listitem>
        </itemizedlist>

        <note>
            <para>
                When looking for relations in the page instance
                (<code>$page->getRel($type)</code> or
                <code>$page->getRev($type)</code>), the helper accepts the
                values of type <type>String</type>, <type>Array</type>,
                <classname>Zend_Config</classname>, or
                <classname>Zend_Navigation_Page</classname>. If a string
                is found, it will be converted to a
                <classname>Zend_Navigation_Page_Uri</classname>. If an array
                or a config is found, it will be converted to one or several
                page instances. If the first key of the array/config is numeric,
                it will be considered to contain several pages, and each
                element will be passed to the
                <link linkend="zend.navigation.pages.factory">page factory</link>.
                If the first key is not numeric, the array/config will be
                passed to the page factory directly, and a single page will
                be returned.
            </para>
        </note>

        <para>
            The helper also supports magic methods for finding relations.
            E.g. to find forward alternate relations, call
            <code>$helper->findRelAlternate($page)</code>, and to find
            reverse section relations, call
            <code>$helper->findRevSection($page)</code>. Those calls correspond
            to <code>$helper->findRelation($page, 'rel', 'alternate');</code>
            and <code>$helper->findRelation($page, 'rev', 'section');</code>
            respectively.
        </para>

        <para>
            To customize which relations should be rendered, the helper
            uses a render flag. The render flag is an integer value, and will be
            used in a
            <ulink url="http://php.net/manual/en/language.operators.bitwise.php">bitwse
            <code>and</code> (<code>&amp;</code>) operation</ulink> against the
            helper's render constants to determine if the relation that belongs
            to the render constant should be rendered.
        </para>
        <para>
            See the
            <link linkend="zend.view.helpers.initial.navigation.links.example3">example
            below</link> for more information.
        </para>

        <itemizedlist>
            <listitem>
                <para>
                    <constant>Zend_View_Helper_Navigation_Link::RENDER_ALTERNATE</constant>
                </para>
            </listitem>
            <listitem>
                <para>
                    <constant>Zend_View_Helper_Navigation_Link::RENDER_STYLESHEET</constant>
                </para>
            </listitem>
            <listitem>
                <para>
                    <constant>Zend_View_Helper_Navigation_Link::RENDER_START</constant>
                </para>
            </listitem>
            <listitem>
                <para>
                    <constant>Zend_View_Helper_Navigation_Link::RENDER_NEXT</constant>
                </para>
            </listitem>
            <listitem>
                <para>
                    <constant>Zend_View_Helper_Navigation_Link::RENDER_PREV</constant>
                </para>
            </listitem>
            <listitem>
                <para>
                    <constant>Zend_View_Helper_Navigation_Link::RENDER_CONTENTS</constant>
                </para>
            </listitem>
            <listitem>
                <para>
                    <constant>Zend_View_Helper_Navigation_Link::RENDER_INDEX</constant>
                </para>
            </listitem>
            <listitem>
                <para>
                    <constant>Zend_View_Helper_Navigation_Link::RENDER_GLOSSARY</constant>
                </para>
            </listitem>
            <listitem>
                <para>
                    <constant>Zend_View_Helper_Navigation_Link::RENDER_COPYRIGHT</constant>
                </para>
            </listitem>
            <listitem>
                <para>
                    <constant>Zend_View_Helper_Navigation_Link::RENDER_CHAPTER</constant>
                </para>
            </listitem>
            <listitem>
                <para>
                    <constant>Zend_View_Helper_Navigation_Link::RENDER_SECTION</constant>
                </para>
            </listitem>
            <listitem>
                <para>
                    <constant>Zend_View_Helper_Navigation_Link::RENDER_SUBSECTION</constant>
                </para>
            </listitem>
            <listitem>
                <para>
                    <constant>Zend_View_Helper_Navigation_Link::RENDER_APPENDIX</constant>
                </para>
            </listitem>
            <listitem>
                <para>
                    <constant>Zend_View_Helper_Navigation_Link::RENDER_HELP</constant>
                </para>
            </listitem>
            <listitem>
                <para>
                    <constant>Zend_View_Helper_Navigation_Link::RENDER_BOOKMARK</constant>
                </para>
            </listitem>
            <listitem>
                <para>
                    <constant>Zend_View_Helper_Navigation_Link::RENDER_CUSTOM</constant>
                </para>
            </listitem>
            <listitem>
                <para>
                    <constant>Zend_View_Helper_Navigation_Link::RENDER_ALL</constant>
                </para>
            </listitem>
        </itemizedlist>

        <para>
            The constants from <constant>RENDER_ALTERNATE</constant> to
            <constant>RENDER_BOOKMARK</constant> denote standard HTML link types.
            <constant>RENDER_CUSTOM</constant> denotes non-standard relations that
            specified in pages. <constant>RENDER_ALL</constant> denotes standard and
            non-standard relations.
        </para>

        <para>
            Methods in the links helper:
        </para>

        <itemizedlist>
            <listitem>
                <para>
                    <code>{get|set}RenderFlag()</code> gets/sets the render
                    flag. Default is <constant>RENDER_ALL</constant>. See examples
                    below on how to set the render flag.
                </para>
            </listitem>
            <listitem>
                <para>
                    <methodname>findAllRelations()</methodname> finds all relations of
                    all types for a given page.
                </para>
            </listitem>
            <listitem>
                <para>
                    <methodname>findRelation()</methodname> finds all relations of a given
                    type from a given page.
                </para>
            </listitem>
            <listitem>
                <para>
                    <code>searchRel{Start|Next|Prev|Chapter|Section|Subsection}()</code>
                    traverses a container to find forward relations to
                    the start page, the next page, the previous page,
                    chapters, sections, and subsections.
                </para>
            </listitem>
            <listitem>
                <para>
                    <code>searchRev{Section|Subsection}()</code> traverses
                    a container to find reverse relations to sections or
                    subsections.
                </para>
            </listitem>
            <listitem>
                <para>
                    <methodname>renderLink()</methodname> renders a single <code>link</code>
                    element.
                </para>
            </listitem>
        </itemizedlist>

        <example id="zend.view.helpers.initial.navigation.links.example1">
            <title>Specify relations in pages</title>

            <para>
                This example shows how to specify relations in pages.
            </para>

            <programlisting language="php"><![CDATA[
$container = new Zend_Navigation(array(
    array(
        'label' => 'Relations using strings',
        'rel'   => array(
            'alternate' => 'http://www.example.org/'
        ),
        'rev'   => array(
            'alternate' => 'http://www.example.net/'
        )
    ),
    array(
        'label' => 'Relations using arrays',
        'rel'   => array(
            'alternate' => array(
                'label' => 'Example.org',
                'uri'   => 'http://www.example.org/'
            )
        )
    ),
    array(
        'label' => 'Relations using configs',
        'rel'   => array(
            'alternate' => new Zend_Config(array(
                'label' => 'Example.org',
                'uri'   => 'http://www.example.org/'
            ))
        )
    ),
    array(
        'label' => 'Relations using pages instance',
        'rel'   => array(
            'alternate' => Zend_Navigation_Page::factory(array(
                'label' => 'Example.org',
                'uri'   => 'http://www.example.org/'
            ))
        )
    )
));
]]></programlisting>
        </example>

        <example id="zend.view.helpers.initial.navigation.links.example2">
            <title>Default rendering of links</title>

            <para>
                This example shows how to render a menu from a container
                registered/found in the view helper.
            </para>

            <programlisting language="php"><![CDATA[
In a view script or layout:
<?php echo $this->view->navigation()->links(); ?>

Output:
<link rel="alternate" href="/products/server/faq/format/xml">
<link rel="start" href="/" title="Home">
<link rel="next" href="/products/server/editions" title="Editions">
<link rel="prev" href="/products/server" title="Foo Server">
<link rel="chapter" href="/products" title="Products">
<link rel="chapter" href="/company/about" title="Company">
<link rel="chapter" href="/community" title="Community">
<link rel="canonical" href="http://www.example.com/?page=server-faq">
<link rev="subsection" href="/products/server" title="Foo Server">
]]></programlisting>
        </example>

        <example id="zend.view.helpers.initial.navigation.links.example3">
            <title>Specify which relations to render</title>

            <para>
                This example shows how to specify which relations to find
                and render.
            </para>

            <programlisting language="php"><![CDATA[
Render only start, next, and prev:
$helper->setRenderFlag(Zend_View_Helper_Navigation_Links::RENDER_START |
                       Zend_View_Helper_Navigation_Links::RENDER_NEXT |
                       Zend_View_Helper_Navigation_Links::RENDER_PREV);

Output:
<link rel="start" href="/" title="Home">
<link rel="next" href="/products/server/editions" title="Editions">
<link rel="prev" href="/products/server" title="Foo Server">
]]></programlisting>

            <programlisting language="php"><![CDATA[
Render only native link types:
$helper->setRenderFlag(Zend_View_Helper_Navigation_Links::RENDER_ALL ^
                       Zend_View_Helper_Navigation_Links::RENDER_CUSTOM);

Output:
<link rel="alternate" href="/products/server/faq/format/xml">
<link rel="start" href="/" title="Home">
<link rel="next" href="/products/server/editions" title="Editions">
<link rel="prev" href="/products/server" title="Foo Server">
<link rel="chapter" href="/products" title="Products">
<link rel="chapter" href="/company/about" title="Company">
<link rel="chapter" href="/community" title="Community">
<link rev="subsection" href="/products/server" title="Foo Server">
]]></programlisting>

            <programlisting language="php"><![CDATA[
Render all but chapter:
$helper->setRenderFlag(Zend_View_Helper_Navigation_Links::RENDER_ALL ^
                       Zend_View_Helper_Navigation_Links::RENDER_CHAPTER);

Output:
<link rel="alternate" href="/products/server/faq/format/xml">
<link rel="start" href="/" title="Home">
<link rel="next" href="/products/server/editions" title="Editions">
<link rel="prev" href="/products/server" title="Foo Server">
<link rel="canonical" href="http://www.example.com/?page=server-faq">
<link rev="subsection" href="/products/server" title="Foo Server">
]]></programlisting>
        </example>
    </sect4>

    <sect4 id="zend.view.helpers.initial.navigation.menu">
        <title>Menu Helper</title>

        <para>
            The Menu helper is used for rendering menus from navigation
            containers. By default, the menu will be rendered using
            HTML <code>UL</code> and <code>LI</code> tags, but the helper also
            allows using a partial view script.
        </para>

        <para>
            Methods in the Menu helper:
        </para>

        <itemizedlist>
            <listitem>
                <para>
                    <code>{get|set}UlClass()</code> gets/sets the <acronym>CSS</acronym> class
                    used in <methodname>renderMenu()</methodname>.
                </para>
            </listitem>
            <listitem>
                <para>
                    <code>{get|set}OnlyActiveBranch()</code> gets/sets a flag
                    specifying whether only the active branch of a container
                    should be rendered.
                </para>
            </listitem>
            <listitem>
                <para>
                    <code>{get|set}RenderParents()</code> gets/sets a flag
                    specifying whether parents should be rendered when only
                    rendering active branch of a container. If set to
                    <constant>FALSE</constant>, only the deepest active menu will be
                    rendered.
                </para>
            </listitem>
            <listitem>
                <para>
                    <code>{get|set}Partial()</code> gets/sets a partial view
                    script that should be used for rendering menu.
                    If a partial view script is set, the helper's
                    <methodname>render()</methodname> method will use the
                    <methodname>renderPartial()</methodname> method. If no partial is
                    set, the <methodname>renderMenu()</methodname> method is used.
                    The helper expects the partial to be a <type>String</type>
                    or an <type>Array</type> with two elements. If the partial
                    is a <type>String</type>, it denotes the name of the partial
                    script to use. If it is an <type>Array</type>, the first
                    element will be used as the name of the partial view
                    script, and the second element is the module where the
                    script is found.
                </para>
            </listitem>
            <listitem>
                <para>
                    <methodname>htmlify()</methodname> overrides the method from the
                    abstract class to return <code>span</code> elements
                    if the page has no <code>href</code>.
                </para>
            </listitem>
            <listitem>
                <para>
                    <methodname>renderMenu($container = null, $options = array())</methodname>
                    is the default render method, and will render a container as
                    a HTML <code>UL</code> list.
                </para>
                <para>
                    If <varname>$container</varname> is not given, the container
                    registered in the helper will be rendered.
                </para>
                <para>
                    <varname>$options</varname> is used for overriding options
                    specified temporarily without rsetting the values in the
                    helper instance. It is an associative array where each key
                    corresponds to an option in the helper.
                </para>
                <para>
                    Recognized options:
                </para>

                <itemizedlist>
                    <listitem>
                        <para>
                            <code>indent</code>; indentation. Expects a
                            <type>String</type> or an <code>int</code>
                            value.
                        </para>
                    </listitem>
                    <listitem>
                        <para>
                            <code>minDepth</code>; minimum depth. Expcects
                            an <code>int</code> or <constant>NULL</constant> (no
                            minimum depth).
                        </para>
                    </listitem>
                    <listitem>
                        <para>
                            <code>maxDepth</code>; maximum depth. Expcects
                            an <code>int</code> or <constant>NULL</constant> (no
                            maximum depth).
                        </para>
                    </listitem>
                    <listitem>
                        <para>
                            <code>ulClass</code>; <acronym>CSS</acronym> class for
                            <code>ul</code> element. Expects a
                            <type>String</type>.
                        </para>
                    </listitem>
                    <listitem>
                        <para>
                            <code>onlyActiveBranch</code>; whether only
                            active branch should be rendered. Expects
                            a <type>Boolean</type> value.
                        </para>
                    </listitem>
                    <listitem>
                        <para>
                            <code>renderParents</code>; whether parents
                            should be rendered if only rendering active
                            branch. Expects a <type>Boolean</type> value.
                        </para>
                    </listitem>
                </itemizedlist>

                <para>
                    If an option is not given, the value set in the helper
                    will be used.
                </para>
            </listitem>
            <listitem>
                <para>
                    <methodname>renderPartial()</methodname> is used for rendering the menu
                    using a partial view script.
                </para>
            </listitem>
            <listitem>
                <para>
                    <methodname>renderSubMenu()</methodname> renders the deepest menu level
                    of a container's active branch.
                </para>
            </listitem>
       </itemizedlist>

        <example id="zend.view.helpers.initial.navigation.menu.example1">
            <title>Rendering a menu</title>

            <para>
                This example shows how to render a menu from a container
                registered/found in the view helper. Notice how pages
                are filtered out based on visibility and <acronym>ACL</acronym>.
            </para>

            <programlisting language="php"><![CDATA[
In a view script or layout:
<?php echo $this->navigation()->menu()->render() ?>

Or simply:
<?php echo $this->navigation()->menu() ?>

Output:
<ul class="navigation">
    <li>
        <a title="Go Home" href="/">Home</a>
    </li>
    <li class="active">
        <a href="/products">Products</a>
        <ul>
            <li class="active">
                <a href="/products/server">Foo Server</a>
                <ul>
                    <li class="active">
                        <a href="/products/server/faq">FAQ</a>
                    </li>
                    <li>
                        <a href="/products/server/editions">Editions</a>
                    </li>
                    <li>
                        <a href="/products/server/requirements">System Requirements</a>
                    </li>
                </ul>
            </li>
            <li>
                <a href="/products/studio">Foo Studio</a>
                <ul>
                    <li>
                        <a href="/products/studio/customers">Customer Stories</a>
                    </li>
                    <li>
                        <a href="/prodcts/studio/support">Support</a>
                    </li>
                </ul>
            </li>
        </ul>
    </li>
    <li>
        <a title="About us" href="/company/about">Company</a>
        <ul>
            <li>
                <a href="/company/about/investors">Investor Relations</a>
            </li>
            <li>
                <a class="rss" href="/company/news">News</a>
                <ul>
                    <li>
                        <a href="/company/news/press">Press Releases</a>
                    </li>
                    <li>
                        <a href="/archive">Archive</a>
                    </li>
                </ul>
            </li>
        </ul>
    </li>
    <li>
        <a href="/community">Community</a>
        <ul>
            <li>
                <a href="/community/account">My Account</a>
            </li>
            <li>
                <a class="external" href="http://forums.example.com/">Forums</a>
            </li>
        </ul>
    </li>
</ul>
]]></programlisting>
        </example>

        <example id="zend.view.helpers.initial.navigation.menu.example2">
            <title>Calling renderMenu() directly</title>

            <para>
                This example shows how to render a menu that is not
                registered in the view helper by calling the
                <methodname>renderMenu()</methodname> directly and specifying a few
                options.
            </para>

            <programlisting language="php"><![CDATA[
<?php
// render only the 'Community' menu
$community = $this->navigation()->findOneByLabel('Community');
$options = array(
    'indent'  => 16,
    'ulClass' => 'community'
);
echo $this->navigation()
          ->menu()
          ->renderMenu($community, $options);
?>
Output:
                <ul class="community">
                    <li>
                        <a href="/community/account">My Account</a>
                    </li>
                    <li>
                        <a class="external" href="http://forums.example.com/">Forums</a>
                    </li>
                </ul>
]]></programlisting>
        </example>

        <example id="zend.view.helpers.initial.navigation.menu.example3">
            <title>Rendering the deepest active menu</title>

            <para>
                This example shows how the <methodname>renderSubMenu()</methodname>
                will render the deepest sub menu of the active branch.
            </para>

            <para>
                Calling <methodname>renderSubMenu($container, $ulClass, $indent)</methodname>
                is equivalent to calling <methodname>renderMenu($container, $options)</methodname>
                with the following options:
            </para>

            <programlisting language="php"><![CDATA[
array(
    'ulClass'          => $ulClass,
    'indent'           => $indent,
    'minDepth'         => null,
    'maxDepth'         => null,
    'onlyActiveBranch' => true,
    'renderParents'    => false
);
]]></programlisting>

            <programlisting language="php"><![CDATA[
<?php
echo $this->navigation()
          ->menu()
          ->renderSubMenu(null, 'sidebar', 4);
?>

The output will be the same if 'FAQ' or 'Foo Server' is active:
    <ul class="sidebar">
        <li class="active">
            <a href="/products/server/faq">FAQ</a>
        </li>
        <li>
            <a href="/products/server/editions">Editions</a>
        </li>
        <li>
            <a href="/products/server/requirements">System Requirements</a>
        </li>
    </ul>
]]></programlisting>
        </example>

        <example id="zend.view.helpers.initial.navigation.menu.example4">
            <title>Rendering a menu with maximum depth</title>

            <programlisting language="php"><![CDATA[
<?php
echo $this->navigation()
          ->menu()
          ->setMaxDepth(1);
?>

Output:
<ul class="navigation">
    <li>
        <a title="Go Home" href="/">Home</a>
    </li>
    <li class="active">
        <a href="/products">Products</a>
        <ul>
            <li class="active">
                <a href="/products/server">Foo Server</a>
            </li>
            <li>
                <a href="/products/studio">Foo Studio</a>
            </li>
        </ul>
    </li>
    <li>
        <a title="About us" href="/company/about">Company</a>
        <ul>
            <li>
                <a href="/company/about/investors">Investor Relations</a>
            </li>
            <li>
                <a class="rss" href="/company/news">News</a>
            </li>
        </ul>
    </li>
    <li>
        <a href="/community">Community</a>
        <ul>
            <li>
                <a href="/community/account">My Account</a>
            </li>
            <li>
                <a class="external" href="http://forums.example.com/">Forums</a>
            </li>
        </ul>
    </li>
</ul>
]]></programlisting>
        </example>

        <example id="zend.view.helpers.initial.navigation.menu.example5">
            <title>Rendering a menu with minimum depth</title>

            <programlisting language="php"><![CDATA[
<?php
echo $this->navigation()
          ->menu()
          ->setMinDepth(1);
?>

Output:
<ul class="navigation">
    <li class="active">
        <a href="/products/server">Foo Server</a>
        <ul>
            <li class="active">
                <a href="/products/server/faq">FAQ</a>
            </li>
            <li>
                <a href="/products/server/editions">Editions</a>
            </li>
            <li>
                <a href="/products/server/requirements">System Requirements</a>
            </li>
        </ul>
    </li>
    <li>
        <a href="/products/studio">Foo Studio</a>
        <ul>
            <li>
                <a href="/products/studio/customers">Customer Stories</a>
            </li>
            <li>
                <a href="/prodcts/studio/support">Support</a>
            </li>
        </ul>
    </li>
    <li>
        <a href="/company/about/investors">Investor Relations</a>
    </li>
    <li>
        <a class="rss" href="/company/news">News</a>
        <ul>
            <li>
                <a href="/company/news/press">Press Releases</a>
            </li>
            <li>
                <a href="/archive">Archive</a>
            </li>
        </ul>
    </li>
    <li>
        <a href="/community/account">My Account</a>
    </li>
    <li>
        <a class="external" href="http://forums.example.com/">Forums</a>
    </li>
</ul>
]]></programlisting>
        </example>

        <example id="zend.view.helpers.initial.navigation.menu.example6">
            <title>Rendering only the active branch of a menu</title>

            <programlisting language="php"><![CDATA[
<?php
echo $this->navigation()
          ->menu()
          ->setOnlyActiveBranch(true);
?>

Output:
<ul class="navigation">
    <li class="active">
        <a href="/products">Products</a>
        <ul>
            <li class="active">
                <a href="/products/server">Foo Server</a>
                <ul>
                    <li class="active">
                        <a href="/products/server/faq">FAQ</a>
                    </li>
                    <li>
                        <a href="/products/server/editions">Editions</a>
                    </li>
                    <li>
                        <a href="/products/server/requirements">System Requirements</a>
                    </li>
                </ul>
            </li>
        </ul>
    </li>
</ul>
]]></programlisting>
        </example>

        <example id="zend.view.helpers.initial.navigation.menu.example7">
            <title>
                Rendering only the active branch of a menu with minimum depth
            </title>

            <programlisting language="php"><![CDATA[
<?php
echo $this->navigation()
          ->menu()
          ->setOnlyActiveBranch(true)
          ->setMinDepth(1);
?>

Output:
<ul class="navigation">
    <li class="active">
        <a href="/products/server">Foo Server</a>
        <ul>
            <li class="active">
                <a href="/products/server/faq">FAQ</a>
            </li>
            <li>
                <a href="/products/server/editions">Editions</a>
            </li>
            <li>
                <a href="/products/server/requirements">System Requirements</a>
            </li>
        </ul>
    </li>
</ul>
]]></programlisting>
        </example>

        <example id="zend.view.helpers.initial.navigation.menu.example8">
            <title>
                Rendering only the active branch of a menu with maximum depth
            </title>

            <programlisting language="php"><![CDATA[
<?php
echo $this->navigation()
          ->menu()
          ->setOnlyActiveBranch(true)
          ->setMaxDepth(1);
?>

Output:
<ul class="navigation">
    <li class="active">
        <a href="/products">Products</a>
        <ul>
            <li class="active">
                <a href="/products/server">Foo Server</a>
            </li>
            <li>
                <a href="/products/studio">Foo Studio</a>
            </li>
        </ul>
    </li>
</ul>
]]></programlisting>
        </example>

        <example id="zend.view.helpers.initial.navigation.menu.example9">
            <title>
                Rendering only the active branch of a menu with maximum depth
                and no parents
            </title>

            <para>
            </para>

            <programlisting language="php"><![CDATA[
<?php
echo $this->navigation()
          ->menu()
          ->setOnlyActiveBranch(true)
          ->setRenderParents(false)
          ->setMaxDepth(1);
?>

Output:
<ul class="navigation">
    <li class="active">
        <a href="/products/server">Foo Server</a>
    </li>
    <li>
        <a href="/products/studio">Foo Studio</a>
    </li>
</ul>
]]></programlisting>
        </example>

        <example id="zend.view.helpers.initial.navigation.menu.example10">
            <title>Rendering a custom menu using a partial view script</title>

            <para>
                This example shows how to render a custom menu using
                a partial vew script. By calling <methodname>setPartial()</methodname>,
                you can specify a partial view script that will be used
                when calling <methodname>render()</methodname>. When a partial is specified,
                the <methodname>renderPartial()</methodname> method will be called. This
                method will assign the container to the view with the key
                <code>container</code>.
            </para>

            <para>In a layout:</para>

            <programlisting language="php"><![CDATA[
$partial = array('menu.phtml', 'default');
$this->navigation()->menu()->setPartial($partial);
echo $this->navigation()->menu()->render();
]]></programlisting>

            <para>In application/modules/default/views/menu.phtml:</para>

            <programlisting language="php"><![CDATA[
foreach ($this->container as $page) {
    echo $this->navigation()->menu()->htmlify($page), PHP_EOL;
}
]]></programlisting>

            <para>Output:</para>

            <programlisting language="php"><![CDATA[
<a title="Go Home" href="/">Home</a>
<a href="/products">Products</a>
<a title="About us" href="/company/about">Company</a>
<a href="/community">Community</a>
]]></programlisting>
        </example>
    </sect4>

    <sect4 id="zend.view.helpers.initial.navigation.sitemap">
        <title>Sitemap Helper</title>

        <para>
            The Sitemap helper is used for generating <acronym>XML</acronym> sitemaps, as
            defined by the <ulink
                url="http://www.sitemaps.org/protocol.php">Sitemaps <acronym>XML</acronym> format</ulink>.
            Read more about <ulink url="http://en.wikipedia.org/wiki/Sitemaps">Sitemaps
            on Wikpedia</ulink>.
        </para>

        <para>
            By default, the sitemap helper uses
            <link linkend="zend.validate.sitemap">sitemap validators</link>
            to validate each element that is rendered. This can be disabled by
            calling <code>$helper->setUseSitemapValidators(false)</code>.
        </para>

        <note>
            <para>
                If you disable sitemap validators, the custom properties (see table)
                are not validated at all.
            </para>
        </note>

        <para>
            The sitemap helper also supports <ulink
                url="http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd">Sitemap XSD
                Schema</ulink> validation of the generated sitemap. This is disabled by default,
            since it will require a request to the Schema file. It can be
            enabled with
            <code>$helper->setUseSchemaValidation(true)</code>.
        </para>

        <table id="zend.view.helpers.initial.navigation.sitemap.elements">
            <title>Sitemap XML elements</title>
            <tgroup cols="2">
                <thead>
                    <row>
                        <entry>Element</entry>
                        <entry>Description</entry>
                    </row>
                </thead>
                <tbody>
                    <row>
                        <entry><code>loc</code></entry>
                        <entry>
                            Absolute <acronym>URL</acronym> to page. An absolute <acronym>URL</acronym> will
                            be generated by the helper.
                        </entry>
                    </row>
                    <row>
                        <entry><code>lastmod</code></entry>
                        <entry>
                            <para>
                                The date of last modification of the file, in <ulink
                                    url="http://www.w3.org/TR/NOTE-datetime">W3C Datetime</ulink>
                                format. This time portion can be omitted if desired, and only use
                                YYYY-MM-DD.
                            </para>
                            <para>
                                The helper will try to retrieve the
                                <code>lastmod</code> value from the page's
                                custom property <code>lastmod</code> if it
                                is set in the page. If the value is not a
                                valid date, it is ignored.
                            </para>
                        </entry>
                    </row>
                    <row>
                        <entry><code>changefreq</code></entry>
                        <entry>
                            <para>
                                How frequently the page is likely to change.
                                This value provides general information to
                                search engines and may not correlate exactly
                                to how often they crawl the page. Valid
                                values are:
                            </para>

                            <itemizedlist>
                                <listitem><para>always</para></listitem>
                                <listitem><para>hourly</para></listitem>
                                <listitem><para>daily</para></listitem>
                                <listitem><para>weekly</para></listitem>
                                <listitem><para>monthly</para></listitem>
                                <listitem><para>yearly</para></listitem>
                                <listitem><para>never</para></listitem>
                            </itemizedlist>

                            <para>
                                The helper will try to retrieve the
                                <code>changefreq</code> value from the page's
                                custom property <code>changefreq</code> if it
                                is set in the page. If the value is not
                                valid, it is ignored.
                            </para>
                        </entry>
                    </row>
                    <row>
                        <entry><code>priority</code></entry>
                        <entry>
                            <para>
                                The priority of this <acronym>URL</acronym> relative to other
                                <acronym>URL</acronym>s on your site. Valid values range from
                                0.0 to 1.0.
                            </para>
                            <para>
                                The helper will try to retrieve the
                                <code>priority</code> value from the page's
                                custom property <code>priority</code> if it
                                is set in the page. If the value is not
                                valid, it is ignored.
                            </para>
                        </entry>
                    </row>
                </tbody>
            </tgroup>
        </table>

        <para>
            Methods in the sitemap helper:
        </para>

        <itemizedlist>
           <listitem>
                <para>
                    <code>{get|set}FormatOutput()</code> gets/sets a flag
                    indicating whether <acronym>XML</acronym> output should be formatted. This
                    corresponds to the <code>formatOutput</code> property
                    of the native <classname>DOMDocument</classname> class.
                    Read more at
                    <ulink url="http://php.net/domdocument">PHP: DOMDocument - Manual</ulink>.
                    Default is <constant>FALSE</constant>.
                </para>
           </listitem>
           <listitem>
                <para>
                    <code>{get|set}UseXmlDeclaration()</code> gets/sets a
                    flag indicating whether the <acronym>XML</acronym> declaration should be
                    included when rendering. Default is <constant>TRUE</constant>.
                </para>
           </listitem>
           <listitem>
                <para>
                    <code>{get|set}UseSitemapValidators()</code> gets/sets a
                    flag indicating whether sitemap validators should be
                    used when generating the DOM sitemap. Default is
                    <constant>TRUE</constant>.
                </para>
           </listitem>
           <listitem>
                <para>
                    <code>{get|set}UseSchemaValidation()</code> gets/sets a
                    flag indicating whether the helper should use <acronym>XML</acronym> Schema
                    validation when generating the DOM sitemap. Default is
                    <constant>FALSE</constant>. If <constant>TRUE</constant>.
                </para>
           </listitem>
           <listitem>
                <para>
                    <code>{get|set}ServerUrl()</code> gets/sets server <acronym>URL</acronym>
                    that will be prepended to non-absolute <acronym>URL</acronym>s in the
                    <methodname>url()</methodname> method. If no server <acronym>URL</acronym> is specified,
                    it will be determined by the helper.
                </para>
           </listitem>
           <listitem>
                <para>
                    <methodname>url()</methodname> is used to generate absolute <acronym>URL</acronym>s to
                    pages.
                </para>
           </listitem>
           <listitem>
                <para>
                    <methodname>getDomSitemap()</methodname> generates a DOMDocument
                    from a given container.
                </para>
           </listitem>
       </itemizedlist>

        <example id="zend.view.helpers.initial.navigation.sitemap.example">
            <title>Rendering an XML sitemap</title>

            <para>
                This example shows how to render an <acronym>XML</acronym> sitemap based
                on the setup we did further up.
            </para>

            <programlisting language="php"><![CDATA[
// In a view script or layout:

// format output
$this->navigation()
      ->sitemap()
      ->setFormatOutput(true); // default is false

// other possible methods:
// ->setUseXmlDeclaration(false); // default is true
// ->setServerUrl('http://my.otherhost.com');
// default is to detect automatically

// print sitemap
echo $this->navigation()->sitemap();
]]></programlisting>

            <para>
                Notice how pages that are invisible or pages with
                <acronym>ACL</acronym> roles incompatible with the view helper are filtered
                out:
            </para>

            <programlisting language="xml"><![CDATA[
<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
  <url>
    <loc>http://www.example.com/</loc>
  </url>
  <url>
    <loc>http://www.example.com/products</loc>
  </url>
  <url>
    <loc>http://www.example.com/products/server</loc>
  </url>
  <url>
    <loc>http://www.example.com/products/server/faq</loc>
  </url>
  <url>
    <loc>http://www.example.com/products/server/editions</loc>
  </url>
  <url>
    <loc>http://www.example.com/products/server/requirements</loc>
  </url>
  <url>
    <loc>http://www.example.com/products/studio</loc>
  </url>
  <url>
    <loc>http://www.example.com/products/studio/customers</loc>
  </url>
  <url>
    <loc>http://www.example.com/prodcts/studio/support</loc>
  </url>
  <url>
    <loc>http://www.example.com/company/about</loc>
  </url>
  <url>
    <loc>http://www.example.com/company/about/investors</loc>
  </url>
  <url>
    <loc>http://www.example.com/company/news</loc>
  </url>
  <url>
    <loc>http://www.example.com/company/news/press</loc>
  </url>
  <url>
    <loc>http://www.example.com/archive</loc>
  </url>
  <url>
    <loc>http://www.example.com/community</loc>
  </url>
  <url>
    <loc>http://www.example.com/community/account</loc>
  </url>
  <url>
    <loc>http://forums.example.com/</loc>
  </url>
</urlset>
]]></programlisting>

            <para>
                Render the sitemap using no <acronym>ACL</acronym> role (should filter out
                /community/account):
            </para>

            <programlisting language="php"><![CDATA[
echo $this->navigation()
          ->sitemap()
          ->setFormatOutput(true)
          ->setRole();
]]></programlisting>

            <programlisting language="xml"><![CDATA[
<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
  <url>
    <loc>http://www.example.com/</loc>
  </url>
  <url>
    <loc>http://www.example.com/products</loc>
  </url>
  <url>
    <loc>http://www.example.com/products/server</loc>
  </url>
  <url>
    <loc>http://www.example.com/products/server/faq</loc>
  </url>
  <url>
    <loc>http://www.example.com/products/server/editions</loc>
  </url>
  <url>
    <loc>http://www.example.com/products/server/requirements</loc>
  </url>
  <url>
    <loc>http://www.example.com/products/studio</loc>
  </url>
  <url>
    <loc>http://www.example.com/products/studio/customers</loc>
  </url>
  <url>
    <loc>http://www.example.com/prodcts/studio/support</loc>
  </url>
  <url>
    <loc>http://www.example.com/company/about</loc>
  </url>
  <url>
    <loc>http://www.example.com/company/about/investors</loc>
  </url>
  <url>
    <loc>http://www.example.com/company/news</loc>
  </url>
  <url>
    <loc>http://www.example.com/company/news/press</loc>
  </url>
  <url>
    <loc>http://www.example.com/archive</loc>
  </url>
  <url>
    <loc>http://www.example.com/community</loc>
  </url>
  <url>
    <loc>http://forums.example.com/</loc>
  </url>
</urlset>
]]></programlisting>

            <para>
                Render the sitemap using a maximum depth of 1.
            </para>

            <programlisting language="php"><![CDATA[
echo $this->navigation()
          ->sitemap()
          ->setFormatOutput(true)
          ->setMaxDepth(1);
]]></programlisting>

            <programlisting language="xml"><![CDATA[
<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
  <url>
    <loc>http://www.example.com/</loc>
  </url>
  <url>
    <loc>http://www.example.com/products</loc>
  </url>
  <url>
    <loc>http://www.example.com/products/server</loc>
  </url>
  <url>
    <loc>http://www.example.com/products/studio</loc>
  </url>
  <url>
    <loc>http://www.example.com/company/about</loc>
  </url>
  <url>
    <loc>http://www.example.com/company/about/investors</loc>
  </url>
  <url>
    <loc>http://www.example.com/company/news</loc>
  </url>
  <url>
    <loc>http://www.example.com/community</loc>
  </url>
  <url>
    <loc>http://www.example.com/community/account</loc>
  </url>
  <url>
    <loc>http://forums.example.com/</loc>
  </url>
</urlset>
]]></programlisting>
        </example>

    </sect4>

    <sect4 id="zend.view.helpers.initial.navigation.navigation">
        <title>Navigation Helper</title>

        <para>
            The Navigation helper is a proxy helper
            that relays calls to other navigational helpers. It can be
            considered an entry point to all navigation-related view tasks.
            The aforementioned navigational helpers are in the namespace
            <classname>Zend_View_Helper_Navigation</classname>, and would thus require
            the path <code>Zend/View/Helper/Navigation</code> to be added as
            a helper path to the view. With the proxy helper residing in the
            <classname>Zend_View_Helper</classname> namespace, it will always be
            available, without the need to add any helper paths to the view.
        </para>

        <para>
            The Navigation helper finds other helpers that implement the
            <classname>Zend_View_Helper_Navigation_Helper</classname>
            interface, which means custom view helpers can also be proxied.
            This would, however, require that the custom helper path is added
            to the view.
        </para>

        <para>
            When proxying to other helpers, the Navigation helper can inject
            its container, <acronym>ACL</acronym>/role, and translator. This means that you
            won't have to explicitly set all three in all navigational
            helpers, nor resort to injecting by means of
            <classname>Zend_Registry</classname> or static methods.
        </para>

        <itemizedlist>
           <listitem>
               <para>
                   <methodname>findHelper()</methodname> finds the given helper,
                   verifies that it is a navigational helper, and injects
                   container, <acronym>ACL</acronym>/role and translator.
               </para>
           </listitem>
           <listitem>
               <para>
                   <code>{get|set}InjectContainer()</code> gets/sets a flag
                   indicating whether the container should be injected to
                   proxied helpers. Default is <constant>TRUE</constant>.
               </para>
           </listitem>
           <listitem>
               <para>
                   <code>{get|set}InjectAcl()</code> gets/sets a flag
                   indicating whether the <acronym>ACL</acronym>/role should be injected to
                   proxied helpers. Default is <constant>TRUE</constant>.
               </para>
           </listitem>
           <listitem>
               <para>
                   <code>{get|set}InjectTranslator()</code> gets/sets a flag
                   indicating whether the translator should be injected to
                   proxied helpers. Default is <constant>TRUE</constant>.
               </para>
           </listitem>
           <listitem>
               <para>
                   <code>{get|set}DefaultProxy()</code> gets/sets the default
                   proxy. Default is <code>'menu'</code>.
               </para>
           </listitem>
           <listitem>
               <para>
                   <methodname>render()</methodname> proxies to the render method of
                   the default proxy.
               </para>
           </listitem>
       </itemizedlist>
    </sect4>
</sect3>