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<h1>Velocity</h1> | |
Velocity is a Java-based template framework which provides the default HTML rending engine | |
for Click. Velocity is very easy to learn, simple to use, and is also very capable. | |
<p> | |
<a href="http://velocity.apache.org/">Velocity</a> is an open source | |
Apache project licensed using the <a href="../LICENSE.txt">Apache</a> Software License. | |
<p> | |
Velocity's comprehensive online documentation is included in this distribution. | |
<ul> | |
<li><a href="user-guide.html">Users Guide</a> - Velocity users guide | |
</li> | |
<li><a href="developer-guide.html">Developers Guide</a> - Velocity developers configuration guide | |
</li> | |
<li><a href="vtl-reference-guide.html">VTL Reference</a> - Velocity Template Language (VTL) reference guide | |
</li> | |
</ul> | |
<p> </p> | |
<h2>Object References</h2> | |
With Click you add objects to your page template using the Page's model. You can then access these objects | |
using Velocities <span class="red">$</span> reference notation. By default the ClickServlet adds the | |
following objects to page templates: | |
<ul style="margin-bottom: 1.5em;"> | |
<li> | |
any public Page fields using the fields name | |
</li> | |
<li><span class="st">context</span> - | |
the Servlet context path, e.g. <span class="blue">/mycorp</span> | |
</li> | |
<li><span class="st">cssImports</span> - | |
the CSS imports and style blocks to include in the pages header. | |
Please see <a href="../click-api/org/apache/click/util/PageImports.html">PageImports</a> | |
for more details. | |
</li> | |
<li><span class="st">format</span> - | |
the <a href="../click-api/org/apache/click/util/Format.html">Format</a> | |
object for formatting the display of objects. | |
</li> | |
<li><span class="st">imports</span> - | |
the CSS and JavaScript imports to include in the pages header. | |
Please see <a href="../click-api/org/apache/click/util/PageImports.html">PageImports</a> | |
for more details. | |
</li> | |
<li><span class="st">jsImports</span> - | |
the JavaScript imports and script blocks to include in the pages footer. | |
Please see <a href="../click-api/org/apache/click/util/PageImports.html">PageImports</a> | |
for more details. | |
</li> | |
<li><span class="st">messages</span> - | |
the <a target="topic" href="../click-api/org/apache/click/util/MessagesMap.html">MessagesMap</a> adaptor | |
for the Page <a href="../click-api/org/apache/click/Page.html#getMessage(java.lang.String)">getMessage()</a> | |
method. | |
</li> | |
<li><span class="st">path</span> - | |
the <a href="../click-api/org/apache/click/Page.html#path">path</a> | |
of the page template to render. | |
</li> | |
<li><span class="st">request</span> - | |
the pages <a class="external" target="_blank" href="http://java.sun.com/products/servlet/2.3/javadoc/javax/servlet/http/HttpServletRequest.html">HttpServletRequest</a> | |
object. | |
</li> | |
<li><span class="st">response</span> - | |
the pages <a class="external" target="_blank" href="http://java.sun.com/products/servlet/2.3/javadoc/javax/servlet/http/HttpServletResponse.html">HttpServletResponse</a> | |
object. | |
</li> | |
<li><span class="st">session</span> - | |
the <a target="topic" href="../click-api/org/apache/click/util/SessionMap.html">SessionMap</a> adaptor | |
for the users <a class="external" target="_blank" href="http://java.sun.com/products/servlet/2.3/javadoc/javax/servlet/http/HttpSession.html">HttpSession</a>. | |
</li> | |
</ul> | |
In your page templates you can access object references using a dot path notation. For example: | |
<pre class="codeHtml"> | |
Welcome: <span class="red">$</span><a target="topic" href="../click-api/org/apache/click/util/SessionMap.html">session</a>.user.fullName | |
</pre> | |
Or by using a more explicit Java notation: | |
<pre class="codeHtml"> | |
Welcome: <span class="red">$</span><a target="topic" href="../click-api/org/apache/click/util/SessionMap.html">session</a>.get("user").getFullName() | |
</pre> | |
<h2>Directives</h2> | |
In Velocity directives are prefixed by a <span class="red">#</span> symbol. While | |
references access stuff, directives do stuff. The full set of Velocity directives are: | |
<ul style="margin-bottom: 1.5em;"> | |
<li><a href="vtl-reference-guide.html#if">#if #elseif #else</a> - | |
output conditional on truth of statements.<p> | |
</li> | |
<li><a href="vtl-reference-guide.html#foreach">#foreach</a> - | |
loops through a list of objects.<p> | |
<p> | |
</li> | |
<li><a href="vtl-reference-guide.html#macro">#macro</a> - | |
allows users to define a Velocimacro (VM), a repeated segment of a VTL template, as required. <p> | |
</li> | |
<li><a href="vtl-reference-guide.html#set">#set</a> - | |
establishes the value of a reference.<p> | |
</li> | |
<li><a href="vtl-reference-guide.html#include">#include</a> - | |
renders local file(s) that are not parsed by Velocity.<p> | |
</li> | |
<li><a href="vtl-reference-guide.html#parse">#parse</a> - | |
renders a local template that is parsed by Velocity. <p> | |
</li> | |
<li><a href="vtl-reference-guide.html#stop">#stop</a> - | |
stops the template engine. <p> | |
</li> | |
</ul> | |
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