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Posted to commits@tapestry.apache.org by bo...@apache.org on 2017/09/16 01:54:20 UTC
svn commit: r1018226 [10/41] - in /websites/production/tapestry/content: ./
cache/ styles/
Modified: websites/production/tapestry/content/component-rendering.html
==============================================================================
--- websites/production/tapestry/content/component-rendering.html (original)
+++ websites/production/tapestry/content/component-rendering.html Sat Sep 16 01:54:19 2017
@@ -27,6 +27,16 @@
</title>
<link type="text/css" rel="stylesheet" href="/resources/space.css" />
+ <link href='/resources/highlighter/styles/shCoreCXF.css' rel='stylesheet' type='text/css' />
+ <link href='/resources/highlighter/styles/shThemeCXF.css' rel='stylesheet' type='text/css' />
+ <script src='/resources/highlighter/scripts/shCore.js' type='text/javascript'></script>
+ <script src='/resources/highlighter/scripts/shBrushJava.js' type='text/javascript'></script>
+ <script src='/resources/highlighter/scripts/shBrushXml.js' type='text/javascript'></script>
+ <script src='/resources/highlighter/scripts/shBrushPlain.js' type='text/javascript'></script>
+ <script>
+ SyntaxHighlighter.defaults['toolbar'] = false;
+ SyntaxHighlighter.all();
+ </script>
<link href="/styles/style.css" rel="stylesheet" type="text/css"/>
@@ -67,7 +77,86 @@
</div>
<div id="content">
- <div id="ConfluenceContent"><p><strong>Rendering of components</strong> in Tapestry 5 is based on a <em>state machine</em> and a <em>queue</em> (instead of the tail recursion used in Tapestry 4). This breaks the rendering process up into tiny pieces that can easily be implemented or overridden. Don't worry, in practice, writing components requires a breathtakingly small amount of code.</p><parameter ac:name="style">float:right</parameter><parameter ac:name="title">Related Articles</parameter><parameter ac:name="class">aui-label</parameter><rich-text-body><parameter ac:name="showLabels">false</parameter><parameter ac:name="showSpace">false</parameter><parameter ac:name="title">Related Articles</parameter><parameter ac:name="cql">label in ("request-processing","rendering") and space = currentSpace()</parameter></rich-text-body><h2 id="ComponentRendering-RenderingPhases">Rendering Phases</h2><p>The rendering of each component is divided into a number of phases, illustra
ted below.</p><p><span class="confluence-embedded-file-wrapper"><img class="confluence-embedded-image" src="component-rendering.data/tapestry_render_phases.png"></span><br clear="none"> Each of the orange phases (SetupRender, BeginRender, BeforeRenderBody, etc.) corresponds to an annotation you may place on one or more methods of your class. The annotation directs Tapestry to invoke your method as part of that phase.</p><p>Methods marked with these annotations are called <strong>render phase methods</strong>.</p><p>Your methods may be void, or return a boolean value. Returning a value can force phases to be skipped, or even be re-visited. In the diagram, solid lines show the normal processing path. Dashed lines are alternate flows that are triggered when your render phase methods return false instead of true (or void).</p><p>Render phase methods may take no parameters, or may take a parameter of type <a href="dom.html">MarkupWriter</a>. The methods can have any visibility you like
... typically, package private is used, as this visibility makes it possible to unit test your code (from within the same Java package) without making the methods part of the component's <em>public</em> API.</p><p>All Render phase methods are <em>optional</em>; a default behavior is associated with each phase.</p><div class="table-wrap"><table class="confluenceTable"><tbody><tr><th colspan="1" rowspan="1" class="confluenceTh"><p>Annotation</p></th><th colspan="1" rowspan="1" class="confluenceTh"><p>Method Name</p></th><th colspan="1" rowspan="1" class="confluenceTh"><p>When Called</p></th></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><strong><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/SetupRender.html">@SetupRender</a></strong></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>setupRender()</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>When initial setup actions, if any, are needed
</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><strong><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/BeginRender">@BeginRender</a></strong></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>beginRender()</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>When Tapestry is ready for the component's start tag, if any, to be rendered</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/BeforeRenderTemplate">@BeforeRenderTemplate</a></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>beforeRenderTemplate()</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Before Tapestry renders the component's template, if any</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><a class="external-link" href="http://tapestry.apache.org/current/
apidocs/org/apache/tapestry5/annotations/BeforeRenderBody">@BeforeRenderBody</a></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>beforeRenderBody()</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Before Tapestry renders the body of the component, if any</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/AfterRenderBody">@AfterRenderBody</a></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>afterRenderBody()</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>After Tapestry renders the body of the component, if any, but before the rest of the component's template is rendered</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/AfterRenderTemplate">@AfterRenderTemplate</a></p></td><td colspan="1" r
owspan="1" class="confluenceTd"><p>afterRenderTemplate()</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>After Tapestry finishes rendering the component's template, if any</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><strong><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/AfterRender">@AfterRender</a></strong></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>afterRender()</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>After Tapestry has finished rendering both the template and body of the component</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><strong><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/CleanupRender">@CleanupRender</a></strong></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>cleanupRender()</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>When fina
l cleanup actions, if any, are needed</p></td></tr></tbody></table></div><p>The large number of phases reflects the need for precise control of components from <a href="component-mixins.html">component mixins</a>. Several of the phases exist almost exclusively for mixins.</p><p>Generally, your code will use the SetupRender, BeginRender, AfterRender and CleanupRender phases ... often just one or two of those.</p><h2 id="ComponentRendering-AnExample">An Example</h2><p>Here's the source for a looping component that counts up or down between two values, renders its body a number of times, and stores the current index value in a parameter:</p><parameter ac:name="">java</parameter><plain-text-body>package org.example.app.components;
+ <div id="ConfluenceContent"><p><strong>Rendering of components</strong> in Tapestry 5 is based on a <em>state machine</em> and a <em>queue</em> (instead of the tail recursion used in Tapestry 4). This breaks the rendering process up into tiny pieces that can easily be implemented or overridden. Don't worry, in practice, writing components requires a breathtakingly small amount of code.</p><div class="aui-label" style="float:right" title="Related Articles">
+
+
+
+
+
+
+
+
+<h3>Related Articles</h3>
+
+<ul class="content-by-label"><li>
+ <div>
+ <span class="icon aui-icon aui-icon-small aui-iconfont-page-default" title="Page">Page:</span> </div>
+
+ <div class="details">
+ <a href="content-type-and-markup.html">Content Type and Markup</a>
+
+
+ </div>
+ </li><li>
+ <div>
+ <span class="icon aui-icon aui-icon-small aui-iconfont-page-default" title="Page">Page:</span> </div>
+
+ <div class="details">
+ <a href="page-navigation.html">Page Navigation</a>
+
+
+ </div>
+ </li><li>
+ <div>
+ <span class="icon aui-icon aui-icon-small aui-iconfont-page-default" title="Page">Page:</span> </div>
+
+ <div class="details">
+ <a href="page-life-cycle.html">Page Life Cycle</a>
+
+
+ </div>
+ </li><li>
+ <div>
+ <span class="icon aui-icon aui-icon-small aui-iconfont-page-default" title="Page">Page:</span> </div>
+
+ <div class="details">
+ <a href="component-rendering.html">Component Rendering</a>
+
+
+ </div>
+ </li><li>
+ <div>
+ <span class="icon aui-icon aui-icon-small aui-iconfont-page-default" title="Page">Page:</span> </div>
+
+ <div class="details">
+ <a href="component-events.html">Component Events</a>
+
+
+ </div>
+ </li><li>
+ <div>
+ <span class="icon aui-icon aui-icon-small aui-iconfont-page-default" title="Page">Page:</span> </div>
+
+ <div class="details">
+ <a href="component-events-faq.html">Component Events FAQ</a>
+
+
+ </div>
+ </li><li>
+ <div>
+ <span class="icon aui-icon aui-icon-small aui-iconfont-page-default" title="Page">Page:</span> </div>
+
+ <div class="details">
+ <a href="request-processing.html">Request Processing</a>
+
+
+ </div>
+ </li></ul>
+</div>
+
+
+<h2 id="ComponentRendering-RenderingPhases">Rendering Phases</h2><p>The rendering of each component is divided into a number of phases, illustrated below.</p><p><span class="confluence-embedded-file-wrapper"><img class="confluence-embedded-image" src="component-rendering.data/tapestry_render_phases.png"></span><br clear="none"> Each of the orange phases (SetupRender, BeginRender, BeforeRenderBody, etc.) corresponds to an annotation you may place on one or more methods of your class. The annotation directs Tapestry to invoke your method as part of that phase.</p><p>Methods marked with these annotations are called <strong>render phase methods</strong>.</p><p>Your methods may be void, or return a boolean value. Returning a value can force phases to be skipped, or even be re-visited. In the diagram, solid lines show the normal processing path. Dashed lines are alternate flows that are triggered when your render phase methods return false instead of true (or void).</p><p>Render phase met
hods may take no parameters, or may take a parameter of type <a href="dom.html">MarkupWriter</a>. The methods can have any visibility you like ... typically, package private is used, as this visibility makes it possible to unit test your code (from within the same Java package) without making the methods part of the component's <em>public</em> API.</p><p>All Render phase methods are <em>optional</em>; a default behavior is associated with each phase.</p><div class="table-wrap"><table class="confluenceTable"><tbody><tr><th colspan="1" rowspan="1" class="confluenceTh"><p>Annotation</p></th><th colspan="1" rowspan="1" class="confluenceTh"><p>Method Name</p></th><th colspan="1" rowspan="1" class="confluenceTh"><p>When Called</p></th></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><strong><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/SetupRender.html">@SetupRender</a></strong></p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p>setupRender()</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>When initial setup actions, if any, are needed</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><strong><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/BeginRender">@BeginRender</a></strong></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>beginRender()</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>When Tapestry is ready for the component's start tag, if any, to be rendered</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/BeforeRenderTemplate">@BeforeRenderTemplate</a></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>beforeRenderTemplate()</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Before Tapestry renders the component's template,
if any</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/BeforeRenderBody">@BeforeRenderBody</a></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>beforeRenderBody()</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Before Tapestry renders the body of the component, if any</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/AfterRenderBody">@AfterRenderBody</a></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>afterRenderBody()</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>After Tapestry renders the body of the component, if any, but before the rest of the component's template is rendered</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><a class="external-link" href="htt
p://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/AfterRenderTemplate">@AfterRenderTemplate</a></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>afterRenderTemplate()</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>After Tapestry finishes rendering the component's template, if any</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><strong><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/AfterRender">@AfterRender</a></strong></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>afterRender()</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>After Tapestry has finished rendering both the template and body of the component</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><strong><a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/CleanupRender">@CleanupRender</a></strong></
p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>cleanupRender()</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>When final cleanup actions, if any, are needed</p></td></tr></tbody></table></div><p>The large number of phases reflects the need for precise control of components from <a href="component-mixins.html">component mixins</a>. Several of the phases exist almost exclusively for mixins.</p><p>Generally, your code will use the SetupRender, BeginRender, AfterRender and CleanupRender phases ... often just one or two of those.</p><h2 id="ComponentRendering-AnExample">An Example</h2><p>Here's the source for a looping component that counts up or down between two values, renders its body a number of times, and stores the current index value in a parameter:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
+<pre class="brush: java; gutter: false; theme: Default" style="font-size:12px;">package org.example.app.components;
import org.apache.tapestry5.annotations.Parameter;
import org.apache.tapestry5.annotations.AfterRender;
@@ -121,11 +210,11 @@ public class Count
return true;
}
}
-</plain-text-body><p>Returning false from next() causes Tapestry to re-run the BeginRender phase, and from there, re-render the component's body (this component does not have a template). Returning true transitions to the CleanupRender phase.</p><p>Notice how Tapestry adapts to your methods, as marked with the annotations. It also adapts in terms of parameters; the two annotated methods here did not perform any output, so they did not need a MarkupWriter.</p><p>What's really mind blowing is that the template and body of a component will often contain ... more components! That means that many different components will be in different phases of their own state machine.</p><h2 id="ComponentRendering-RenderPhasesinDetail">Render Phases in Detail</h2><p><plain-text-body>{float:right|background=#eee|width=50%}
-{note}
-The SetupRender phase, like all render phases, occurs once for each rendering of the component. If the component is inside a looping component ([Loop|http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/corelib/components/Loop.html], [Grid|http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/corelib/components/Grid.html], etc.), then the SetupRender method will be called once for _each_ iteration of the loop.
-{note}
-{float}</plain-text-body></p><h3 id="ComponentRendering-SetupRender">SetupRender</h3><p>The SetupRender phase (see @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/SetupRender.html">SetupRender</a>) is where you can perform any one-time per-render setup for your component. This is a good place to read component parameters and use them to set temporary instance variables.</p><h3 id="ComponentRendering-BeginRender">BeginRender</h3><p>The BeginRender phase (see @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/BeginRender.html">BeginRender</a>) occurs at the start of the rendering of the component. For components that render a tag, the start tag should be rendered here (the close tag should be rendered inside the AfterRender phase). The component can also prevent the template and/or body from being rendered by returning false.</p><p>Components may or may not have a tem
plate. If a component has a template, and the template includes a <body> element, then the BeforeRenderBody phase will be triggered (giving the component the option of rendering its body or not).</p><p>If a component does not have a <body> element in its template, then the BeforeRenderBody phase is not triggered.</p><p>If a component does not have a template, but does have a body, the BeforeRenderBody phase is still triggered.</p><p>If no methods are annotated with BeginRender, then no special output occurs during this phase, but the template (if present) or body (if no template is present, but the component has a body) will be rendered.</p><h3 id="ComponentRendering-BeforeRenderTemplate">BeforeRenderTemplate</h3><p>The BeforeRenderTemplate phase (see @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/BeforeRenderTemplate.html">BeforeRenderTemplate</a>) exists to allow a component to decorate its template (creatin
g markup around the template generated markup), or to allow a component to skip its template.</p><h3 id="ComponentRendering-BeforeRenderBody">BeforeRenderBody</h3><p>The BeforeRenderBody phase (see @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/BeforeRenderBody.html">BeforeRenderBody</a>) is associated with a component's body (the portion of its container's template that the component occupies). The BeforeRenderBody phase allows the component the ability to skip the body, while still rendering the rest of the component's template (if any).</p><p>If no methods are annotated with BeforeRenderBody, then the body will be rendered by default. Again, this occurs when the <body> element of the component's template is reached, or automatically if the component has no template (but the component does have a body).</p><h3 id="ComponentRendering-AfterRenderBody">AfterRenderBody</h3><p>The AfterRenderBody phase (see @<a class=
"external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/AfterRenderBody.html">AfterRenderBody</a>) is executed after the body is rendered; this only occurs for components with a body.</p><h3 id="ComponentRendering-AfterRender">AfterRender</h3><p>The AfterRender phase (see @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/AfterRender.html">AfterRender</a>) complements BeginRender, and is often used to render the close tag that matches the start tag rendered in the BeginRender phase. In any case, the AfterRender phase can continue on to CleanupRender, or revert back to BeginRender (as in our Count component example, above).</p><p>If no methods are annotated with AfterRender, then no special output occurs, and the CleanupRender phase is triggered.</p><h3 id="ComponentRendering-CleanupRender">CleanupRender</h3><p>The CleanupRender phase (see @<a class="external-link" href="http://tapest
ry.apache.org/current/apidocs/org/apache/tapestry5/annotations/CleanupRender.html">CleanupRender</a>) is the counterpart to SetupRender, allowing final cleanup to occur.</p><h2 id="ComponentRendering-UsingMethodNamesinsteadofAnnotations">Using Method Names instead of Annotations</h2><p>If you prefer to avoid using annotations on your methods, you may do so by providing specific names for your methods. The required method name is the annotation name, with the first character decapitalized: setupRender(), beginRender(), etc. As with annotated render phase methods, Tapestry is flexible about visibility, return type and parameters.</p><p>Using this mechanism, the earlier example can be rewritten as:</p><parameter ac:name="">java</parameter><plain-text-body>package org.example.app.components;
+</pre>
+</div></div><p>Returning false from next() causes Tapestry to re-run the BeginRender phase, and from there, re-render the component's body (this component does not have a template). Returning true transitions to the CleanupRender phase.</p><p>Notice how Tapestry adapts to your methods, as marked with the annotations. It also adapts in terms of parameters; the two annotated methods here did not perform any output, so they did not need a MarkupWriter.</p><p>What's really mind blowing is that the template and body of a component will often contain ... more components! That means that many different components will be in different phases of their own state machine.</p><h2 id="ComponentRendering-RenderPhasesinDetail">Render Phases in Detail</h2><p></p><div class="navmenu" style="float:right; width:50%; background:#eee; margin:3px; padding:3px">
+<div class="confluence-information-macro confluence-information-macro-note"><span class="aui-icon aui-icon-small aui-iconfont-warning confluence-information-macro-icon"></span><div class="confluence-information-macro-body">
+<p>The SetupRender phase, like all render phases, occurs once for each rendering of the component. If the component is inside a looping component (<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/corelib/components/Loop.html">Loop</a>, <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/corelib/components/Grid.html">Grid</a>, etc.), then the SetupRender method will be called once for <em>each</em> iteration of the loop.</p></div></div></div><h3 id="ComponentRendering-SetupRender">SetupRender</h3><p>The SetupRender phase (see @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/SetupRender.html">SetupRender</a>) is where you can perform any one-time per-render setup for your component. This is a good place to read component parameters and use them to set temporary instance variables.</p><h3 id="ComponentRendering-BeginRender">BeginRender</
h3><p>The BeginRender phase (see @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/BeginRender.html">BeginRender</a>) occurs at the start of the rendering of the component. For components that render a tag, the start tag should be rendered here (the close tag should be rendered inside the AfterRender phase). The component can also prevent the template and/or body from being rendered by returning false.</p><p>Components may or may not have a template. If a component has a template, and the template includes a <body> element, then the BeforeRenderBody phase will be triggered (giving the component the option of rendering its body or not).</p><p>If a component does not have a <body> element in its template, then the BeforeRenderBody phase is not triggered.</p><p>If a component does not have a template, but does have a body, the BeforeRenderBody phase is still triggered.</p><p>If no methods are annotated with BeginRen
der, then no special output occurs during this phase, but the template (if present) or body (if no template is present, but the component has a body) will be rendered.</p><h3 id="ComponentRendering-BeforeRenderTemplate">BeforeRenderTemplate</h3><p>The BeforeRenderTemplate phase (see @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/BeforeRenderTemplate.html">BeforeRenderTemplate</a>) exists to allow a component to decorate its template (creating markup around the template generated markup), or to allow a component to skip its template.</p><h3 id="ComponentRendering-BeforeRenderBody">BeforeRenderBody</h3><p>The BeforeRenderBody phase (see @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/BeforeRenderBody.html">BeforeRenderBody</a>) is associated with a component's body (the portion of its container's template that the component occupies). The BeforeRenderBody phase al
lows the component the ability to skip the body, while still rendering the rest of the component's template (if any).</p><p>If no methods are annotated with BeforeRenderBody, then the body will be rendered by default. Again, this occurs when the <body> element of the component's template is reached, or automatically if the component has no template (but the component does have a body).</p><h3 id="ComponentRendering-AfterRenderBody">AfterRenderBody</h3><p>The AfterRenderBody phase (see @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/AfterRenderBody.html">AfterRenderBody</a>) is executed after the body is rendered; this only occurs for components with a body.</p><h3 id="ComponentRendering-AfterRender">AfterRender</h3><p>The AfterRender phase (see @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/AfterRender.html">AfterRender</a>) complements BeginRender, and is
often used to render the close tag that matches the start tag rendered in the BeginRender phase. In any case, the AfterRender phase can continue on to CleanupRender, or revert back to BeginRender (as in our Count component example, above).</p><p>If no methods are annotated with AfterRender, then no special output occurs, and the CleanupRender phase is triggered.</p><h3 id="ComponentRendering-CleanupRender">CleanupRender</h3><p>The CleanupRender phase (see @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/CleanupRender.html">CleanupRender</a>) is the counterpart to SetupRender, allowing final cleanup to occur.</p><h2 id="ComponentRendering-UsingMethodNamesinsteadofAnnotations">Using Method Names instead of Annotations</h2><p>If you prefer to avoid using annotations on your methods, you may do so by providing specific names for your methods. The required method name is the annotation name, with the first character decapitaliz
ed: setupRender(), beginRender(), etc. As with annotated render phase methods, Tapestry is flexible about visibility, return type and parameters.</p><p>Using this mechanism, the earlier example can be rewritten as:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
+<pre class="brush: java; gutter: false; theme: Default" style="font-size:12px;">package org.example.app.components;
import org.apache.tapestry5.annotations.Parameter;
@@ -175,7 +264,9 @@ public class Count
return true;
}
}
-</plain-text-body><p>This style is a trade off: on the gain side, the code is <em>even</em> simpler and shorter, and the method names will, by design, be more consistent from one class to the next. The down side is that the names are very generic, and may in some cases, be less descriptive than using annotated methods (<code>initializeValue()</code> and <code>next()</code> are, to some eyes, more descriptive).</p><p>You can, of course, mix and match, using specifically named render phase methods in some cases, and annotated render phase methods in other cases.</p><h2 id="ComponentRendering-RenderingComponents">Rendering Components</h2><p>Instead of returning true or false, a render phase method may return a component. The component may have been injected via the @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/Component.html">Component</a> annotation, or may have been passed to the owning component as a parameter.</p><p>In
any case, returning a component will queue that component to be rendered <strong>before</strong> the active component continues rendering.</p><p>The component to render may even be from a completely different page of the application.</p><p>Recursive rendering of components is not allowed.</p><p>This technique allows the rendering of Tapestry pages to be <em>highly</em> dynamic.</p><p>Returning a component instance does <strong>not</strong> short circuit method invocation (as described below), the way returning a boolean would. It is possible that multiple methods may return components (this is not advised – insanity may ensue).</p><h2 id="ComponentRendering-AdditionalReturnTypes">Additional Return Types</h2><p>Render phase methods may also return <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/Block.html">Blocks</a>, <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/Renderable.html">R
enderables</a> or <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/runtime/RenderCommand.html">RenderCommands</a>.</p><p>The following component returns a Renderable in the BeginRender phase and skips the BeforeRenderTemplate phase:</p><parameter ac:name="lang">java</parameter><plain-text-body>public class OutputValueComponent
+</pre>
+</div></div><p>This style is a trade off: on the gain side, the code is <em>even</em> simpler and shorter, and the method names will, by design, be more consistent from one class to the next. The down side is that the names are very generic, and may in some cases, be less descriptive than using annotated methods (<code>initializeValue()</code> and <code>next()</code> are, to some eyes, more descriptive).</p><p>You can, of course, mix and match, using specifically named render phase methods in some cases, and annotated render phase methods in other cases.</p><h2 id="ComponentRendering-RenderingComponents">Rendering Components</h2><p>Instead of returning true or false, a render phase method may return a component. The component may have been injected via the @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/Component.html">Component</a> annotation, or may have been passed to the owning component as a parameter.</p><p>In any ca
se, returning a component will queue that component to be rendered <strong>before</strong> the active component continues rendering.</p><p>The component to render may even be from a completely different page of the application.</p><p>Recursive rendering of components is not allowed.</p><p>This technique allows the rendering of Tapestry pages to be <em>highly</em> dynamic.</p><p>Returning a component instance does <strong>not</strong> short circuit method invocation (as described below), the way returning a boolean would. It is possible that multiple methods may return components (this is not advised – insanity may ensue).</p><h2 id="ComponentRendering-AdditionalReturnTypes">Additional Return Types</h2><p>Render phase methods may also return <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/Block.html">Blocks</a>, <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/Renderable.html">Rendera
bles</a> or <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/runtime/RenderCommand.html">RenderCommands</a>.</p><p>The following component returns a Renderable in the BeginRender phase and skips the BeforeRenderTemplate phase:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
+<pre class="brush: java; gutter: false; theme: Default" style="font-size:12px;">public class OutputValueComponent
{
@Parameter
private String value;
@@ -191,8 +282,11 @@ public class Count
};
}
}
-</plain-text-body><h2 id="ComponentRendering-ShortCircuiting">Short Circuiting</h2><p>If a method returns a true or false value, this will short circuit processing. Other methods within the phase that would ordinarily be invoked will not be invoked.</p><p>Most render phase methods should return void, to avoid unintentionally short circuiting other methods for the same phase.</p><h2 id="ComponentRendering-MethodConflictsandOrdering">Method Conflicts and Ordering</h2><p>It is possible to have multiple methods that are annotated with the same render phase annotation. This may include methods in the same class, or a mix of method defined in a class and inherited from other classes.</p><h3 id="ComponentRendering-MixinsBeforeComponent">Mixins Before Component</h3><p>When a component has <a href="component-mixins.html">mixins</a>, then the mixins' render phase methods execute <em>before</em> the component's render phase methods. If a mixin extends from a base class, the mixin's parent cla
ss methods execute before the mixin subclass' render phase methods.</p><p>Exception: Mixins whose class is annotated with @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/MixinAfter.html">MixinAfter</a> are ordered <em>after</em> the component, not before.</p><p>The order in which the mixins of a given class (@MixinAfter or mixins before) execute is determined by the ordering constraints specified for the mixins. If no constraints are provided, the order is undefined. See <a href="component-mixins.html">Component Mixins</a> for more details.</p><h3 id="ComponentRendering-ParentsbeforeChild">Parents before Child</h3><p>Ordering is always parent-first. Methods defined in the parent class are always invoked before methods defined in the child class.</p><p>When a sub-class overrides an render phase method of a base class, the method is only invoked once, along with any other base class methods. The subclass can change the <em>
implementation</em> of the base class method via an override, but can't change the <em>timing</em> of when that method is invoked. See <a class="external-link" href="https://issues.apache.org/jira/browse/TAPESTRY-2311">TAPESTRY-2311</a>.</p><h3 id="ComponentRendering-ReverseOrderingforAfterXXXandCleanupRender">Reverse Ordering for AfterXXX and CleanupRender</h3><p>The After_XXX_ phases exists to balance the Begin_XXX_ and Before_XXX_ phases. Often elements will be started inside an earlier phase and then the elements will be ended (closed) inside the corresponding After_XXX_ phase (with the body and template of the component rendering between).</p><p>In order to ensure that operations occur in the correct, and natural order, the render phase methods for these two stages are invoked in <em>reverse order</em>:</p><ul><li>Subclass methods</li><li>Parent class methods</li><li>Mixin subclass methods</li><li>Mixin parent class methods</li></ul><h3 id="ComponentRendering-WithinaSingleClas
s">Within a Single Class</h3><p>Currently, rendering methods having the same annotation within a single class are executed in alphabetical order by method name. Methods with the same name are ordered by number of parameters. Even so, annotating multiple methods with the same rendering phase is not a great idea. Instead, just define one method, and have it call the other methods in the order you desire.</p><h2 id="ComponentRendering-RenderingComments">Rendering Comments</h2><p>Starting with version 5.3, Tapestry can optionally emit rendering comments for all requests; these are comments such as <!--BEGIN Index:loop (context:Index.tml, line 15)--> that can assist you in debugging markup output on the client-side. This will significantly increase the size of the rendered markup, but can be very helpful with complex layouts to determine which component was responsible for which portion of the rendered page.</p><p>Rendering comments are only available when not running in <a href="
configuration.html">production mode</a>.</p><p>To turn on rendering comments for all requests, set the <a href="configuration.html">tapestry.component-render-tracing-enabled</a> configuration symbol to "true".</p><p>To turn on rendering comments only for a particular request, add the query parameter <code>t:component-trace=true</code> to the URL:</p><plain-text-body> http://www.example.com/myapp/mypage?t:component-trace=true
-</plain-text-body></div>
+</pre>
+</div></div><h2 id="ComponentRendering-ShortCircuiting">Short Circuiting</h2><p>If a method returns a true or false value, this will short circuit processing. Other methods within the phase that would ordinarily be invoked will not be invoked.</p><p>Most render phase methods should return void, to avoid unintentionally short circuiting other methods for the same phase.</p><h2 id="ComponentRendering-MethodConflictsandOrdering">Method Conflicts and Ordering</h2><p>It is possible to have multiple methods that are annotated with the same render phase annotation. This may include methods in the same class, or a mix of method defined in a class and inherited from other classes.</p><h3 id="ComponentRendering-MixinsBeforeComponent">Mixins Before Component</h3><p>When a component has <a href="component-mixins.html">mixins</a>, then the mixins' render phase methods execute <em>before</em> the component's render phase methods. If a mixin extends from a base class, the mixin's parent class met
hods execute before the mixin subclass' render phase methods.</p><p>Exception: Mixins whose class is annotated with @<a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/annotations/MixinAfter.html">MixinAfter</a> are ordered <em>after</em> the component, not before.</p><p>The order in which the mixins of a given class (@MixinAfter or mixins before) execute is determined by the ordering constraints specified for the mixins. If no constraints are provided, the order is undefined. See <a href="component-mixins.html">Component Mixins</a> for more details.</p><h3 id="ComponentRendering-ParentsbeforeChild">Parents before Child</h3><p>Ordering is always parent-first. Methods defined in the parent class are always invoked before methods defined in the child class.</p><p>When a sub-class overrides an render phase method of a base class, the method is only invoked once, along with any other base class methods. The subclass can change the <em>implem
entation</em> of the base class method via an override, but can't change the <em>timing</em> of when that method is invoked. See <a class="external-link" href="https://issues.apache.org/jira/browse/TAPESTRY-2311">TAPESTRY-2311</a>.</p><h3 id="ComponentRendering-ReverseOrderingforAfterXXXandCleanupRender">Reverse Ordering for AfterXXX and CleanupRender</h3><p>The After_XXX_ phases exists to balance the Begin_XXX_ and Before_XXX_ phases. Often elements will be started inside an earlier phase and then the elements will be ended (closed) inside the corresponding After_XXX_ phase (with the body and template of the component rendering between).</p><p>In order to ensure that operations occur in the correct, and natural order, the render phase methods for these two stages are invoked in <em>reverse order</em>:</p><ul><li>Subclass methods</li><li>Parent class methods</li><li>Mixin subclass methods</li><li>Mixin parent class methods</li></ul><h3 id="ComponentRendering-WithinaSingleClass">Wit
hin a Single Class</h3><p>Currently, rendering methods having the same annotation within a single class are executed in alphabetical order by method name. Methods with the same name are ordered by number of parameters. Even so, annotating multiple methods with the same rendering phase is not a great idea. Instead, just define one method, and have it call the other methods in the order you desire.</p><h2 id="ComponentRendering-RenderingComments">Rendering Comments</h2><p>Starting with version 5.3, Tapestry can optionally emit rendering comments for all requests; these are comments such as <!--BEGIN Index:loop (context:Index.tml, line 15)--> that can assist you in debugging markup output on the client-side. This will significantly increase the size of the rendered markup, but can be very helpful with complex layouts to determine which component was responsible for which portion of the rendered page.</p><p>Rendering comments are only available when not running in <a href="config
uration.html">production mode</a>.</p><p>To turn on rendering comments for all requests, set the <a href="configuration.html">tapestry.component-render-tracing-enabled</a> configuration symbol to "true".</p><p>To turn on rendering comments only for a particular request, add the query parameter <code>t:component-trace=true</code> to the URL:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
+<pre class="brush: java; gutter: false; theme: Default" style="font-size:12px;"> http://www.example.com/myapp/mypage?t:component-trace=true
+</pre>
+</div></div></div>
</div>
<div class="clearer"></div>