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Posted to commits@tapestry.apache.org by bo...@apache.org on 2017/09/20 12:29:17 UTC
svn commit: r1018410 [41/41] - /websites/production/tapestry/content/
Modified: websites/production/tapestry/content/using-select-with-a-list.html
==============================================================================
--- websites/production/tapestry/content/using-select-with-a-list.html (original)
+++ websites/production/tapestry/content/using-select-with-a-list.html Wed Sep 20 12:29:16 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"/>
@@ -67,13 +77,15 @@
</div>
<div id="content">
- <div id="ConfluenceContent"><plain-text-body>{scrollbar}</plain-text-body><parameter ac:name="hidden">true</parameter><parameter ac:name="atlassian-macro-output-type">BLOCK</parameter><rich-text-body><p>Using SelectModel, SelectModelFactory and ValueEncoder for Select menus populated from a database</p></rich-text-body><h1 id="UsingSelectWithaList-UsingSelectWithaList">Using Select With a List</h1><p>The documentation for the <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/corelib/components/Select.html">Select Component</a> and the <a href="tutorial.html">Tapestry Tutorial</a> provide simplistic examples of populating a drop-down menu (as the (X)HTML <em>Select</em> element) using comma-delimited strings and enums. However, most real-world Tapestry applications need to populate such menus using values from a database, commonly in the form of java.util.List objects. Doing so generally requires a <a class="external-lin
k" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/SelectModel.html">SelectModel</a> and a <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ValueEncoder.html">ValueEncoder</a> bound to the Select component with its "model" and "encoder" parameters:</p><plain-text-body><t:select t:id="colorMenu" value="selectedColor" model="ColorSelectModel" encoder="colorEncoder" />
-</plain-text-body><p>In the above example, ColorSelectModel must be of type SelectModel, or anything that Tapestry knows how to <a href="parameter-type-coercion.html">coerce</a> into a SelectModel, such as a List or a Map or a "value=label,value=label,..." delimited string, or anything Tapestry knows how to coerce into a List or Map, such as an Array or a comma-delimited String.</p><h2 id="UsingSelectWithaList-SelectModel">SelectModel</h2><plain-text-body>{float:right|background=#eee|padding=0 1em}
- *JumpStart Demos:*
- [Total Control Object Select|http://jumpstart.doublenegative.com.au/jumpstart/examples/select/totalcontrolobject]
- [ID Select|http://jumpstart.doublenegative.com.au/jumpstart/examples/select/id]
- [Easy ID Select|http://jumpstart.doublenegative.com.au/jumpstart/examples/select/easyid]
-{float}</plain-text-body><p>A SelectModel is a collection of options (specifically <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/OptionModel.html">OptionModel</a> objects) for a drop-down menu. Basically, each option is a value (an object) and a label (presented to the user).</p><p>If you provide a property of type List for the "model" parameter, Tapestry automatically builds a SelectModel that uses each object's toString() for both the select option value and the select option label. For database-derrived lists this is rarely useful, however, since after form submission you would then have to look up the selected object using that label.</p><p>If you provide a Map, Tapestry builds a SelectModel that uses each item's key as the encoded value and its value as the user-visible label. This is more useful, but if you are going to build a copy of the list as a map just for this purpose, you may as well let Tapestry do it for you, using Se
lectModelFactory.</p><h2 id="UsingSelectWithaList-SelectModelFactory">SelectModelFactory</h2><p>To have Tapestry create a SelectModel for you, use the <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/SelectModelFactory.html">SelectModelFactory</a> service. SelectModelFactory creates a SelectModel from a List of objects (of whatever type) and a label property name that you choose:</p><parameter ac:name="title">SelectWithListDemo.java (a page class)</parameter><plain-text-body>@Property
+ <div id="ConfluenceContent"><h1 id="UsingSelectWithaList-UsingSelectWithaList">Using Select With a List</h1><p>The documentation for the <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/corelib/components/Select.html">Select Component</a> and the <a href="tutorial.html">Tapestry Tutorial</a> provide simplistic examples of populating a drop-down menu (as the (X)HTML <em>Select</em> element) using comma-delimited strings and enums. However, most real-world Tapestry applications need to populate such menus using values from a database, commonly in the form of java.util.List objects. Doing so generally requires a <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/SelectModel.html">SelectModel</a> and a <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ValueEncoder.html">ValueEncoder</a> bound to the Select component with its "model" a
nd "encoder" parameters:</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;"><t:select t:id="colorMenu" value="selectedColor" model="ColorSelectModel" encoder="colorEncoder" />
+</pre>
+</div></div><p>In the above example, ColorSelectModel must be of type SelectModel, or anything that Tapestry knows how to <a href="parameter-type-coercion.html">coerce</a> into a SelectModel, such as a List or a Map or a "value=label,value=label,..." delimited string, or anything Tapestry knows how to coerce into a List or Map, such as an Array or a comma-delimited String.</p><h2 id="UsingSelectWithaList-SelectModel">SelectModel</h2><div class="navmenu" style="float:right; background:#eee; margin:3px; padding:0 1em">
+<p> <strong>JumpStart Demos:</strong><br clear="none">
+ <a class="external-link" href="http://jumpstart.doublenegative.com.au/jumpstart/examples/select/totalcontrolobject" rel="nofollow">Total Control Object Select</a><br clear="none">
+ <a class="external-link" href="http://jumpstart.doublenegative.com.au/jumpstart/examples/select/id" rel="nofollow">ID Select</a><br clear="none">
+ <a class="external-link" href="http://jumpstart.doublenegative.com.au/jumpstart/examples/select/easyid" rel="nofollow">Easy ID Select</a></p></div><p>A SelectModel is a collection of options (specifically <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/OptionModel.html">OptionModel</a> objects) for a drop-down menu. Basically, each option is a value (an object) and a label (presented to the user).</p><p>If you provide a property of type List for the "model" parameter, Tapestry automatically builds a SelectModel that uses each object's toString() for both the select option value and the select option label. For database-derrived lists this is rarely useful, however, since after form submission you would then have to look up the selected object using that label.</p><p>If you provide a Map, Tapestry builds a SelectModel that uses each item's key as the encoded value and its value as the user-visible label. This is more useful, but if
you are going to build a copy of the list as a map just for this purpose, you may as well let Tapestry do it for you, using SelectModelFactory.</p><h2 id="UsingSelectWithaList-SelectModelFactory">SelectModelFactory</h2><p>To have Tapestry create a SelectModel for you, use the <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/SelectModelFactory.html">SelectModelFactory</a> service. SelectModelFactory creates a SelectModel from a List of objects (of whatever type) and a label property name that you choose:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeHeader panelHeader pdl" style="border-bottom-width: 1px;"><b>SelectWithListDemo.java (a page class)</b></div><div class="codeContent panelContent pdl">
+<pre class="brush: java; gutter: false; theme: Default" style="font-size:12px;">@Property
private SelectModel colorSelectModel;
@Inject
SelectModelFactory selectModelFactory;
@@ -85,15 +97,18 @@ void setupRender() {
// create a SelectModel from my list of colors
colorSelectModel = selectModelFactory.create(colors, "name");
}
-</plain-text-body><p>The resulting SelectModel has a selectable option (specifically, an OptionModel) for every object in the original List. The label property name (the "name" property, in this example) determines the user-visible text of each menu option, and your ValueEncoder's toClient() method provides the encoded value (most commonly a simple number). If you don't provide a ValueEncoder, the result of the objects' toString() method (Color#toString() in this example) is used. Although not a recommended practice, you <em>could</em> set your toString() to return the object's ID for this purpose:</p><parameter ac:name="title">Color.java (partial)</parameter><plain-text-body>...
+</pre>
+</div></div><p>The resulting SelectModel has a selectable option (specifically, an OptionModel) for every object in the original List. The label property name (the "name" property, in this example) determines the user-visible text of each menu option, and your ValueEncoder's toClient() method provides the encoded value (most commonly a simple number). If you don't provide a ValueEncoder, the result of the objects' toString() method (Color#toString() in this example) is used. Although not a recommended practice, you <em>could</em> set your toString() to return the object's ID for this purpose:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeHeader panelHeader pdl" style="border-bottom-width: 1px;"><b>Color.java (partial)</b></div><div class="codeContent panelContent pdl">
+<pre class="brush: java; gutter: false; theme: Default" style="font-size:12px;">...
@Override
public String toString() {
return String.valueOf(this.getId());
}
-</plain-text-body><p>But that is contorting the purpose of the toString() method, and if you go to that much trouble you're already half way to the recommended practice: creating a ValueEncoder.</p><h2 id="UsingSelectWithaList-ValueEncoder">ValueEncoder</h2><p>In addition to a SelectModel, your Select menu is likely to need a ValueEncoder. While a SelectModel is concerned only with how to construct a Select menu, a ValueEncoder is used when constructing the Select menu <em>and</em> when interpreting the encoded value that is submitted back to the server. A ValueEncoder is a converter between the type of objects you want to represent as options in the menu and the client-side encoded values that uniquely identify them, and vice-versa.</p><plain-text-body>{float:right|background=#eee|padding=0 1em}
- *JumpStart Demo:*
- [Easy Object Select|http://jumpstart.doublenegative.com.au/jumpstart/examples/select/easyobject]
-{float}</plain-text-body><p>Most commonly, your ValueEncoder's toClient() method will return a unique ID (e.g. a database primary key, or perhaps a UUID) of the given object, and its toValue() method will return the <em>object</em> matching the given ID by doing a database lookup (ideally using a service or DAO method).</p><p>If you're using one of the ORM integration modules (<a href="hibernate.html">Tapestry-Hibernate</a>, <a href="integrating-with-jpa.html">Tapestry-JPA</a>, or <a class="external-link" href="http://code.google.com/p/tapestry5-cayenne/wiki/ValueEncoder" rel="nofollow">Tapestry-Cayenne</a>), the ValueEncoder is automatically provided for each of your mapped entity classes. The Hibernate module's implementation is typical: the primary key field of the object (converted to a String) is used as the client-side value, and that same primary key is used to look up the selected object.</p><p>That's exactly what you should do in your own ValueEncoders too:</p><parameter
ac:name="title">ColorEncoder.java (perhaps in your com.example.myappname.encoders package)</parameter><plain-text-body>public class ColorEncoder implements ValueEncoder<Color>, ValueEncoderFactory<Color> {
+</pre>
+</div></div><p>But that is contorting the purpose of the toString() method, and if you go to that much trouble you're already half way to the recommended practice: creating a ValueEncoder.</p><h2 id="UsingSelectWithaList-ValueEncoder">ValueEncoder</h2><p>In addition to a SelectModel, your Select menu is likely to need a ValueEncoder. While a SelectModel is concerned only with how to construct a Select menu, a ValueEncoder is used when constructing the Select menu <em>and</em> when interpreting the encoded value that is submitted back to the server. A ValueEncoder is a converter between the type of objects you want to represent as options in the menu and the client-side encoded values that uniquely identify them, and vice-versa.</p><div class="navmenu" style="float:right; background:#eee; margin:3px; padding:0 1em">
+<p> <strong>JumpStart Demo:</strong><br clear="none">
+ <a class="external-link" href="http://jumpstart.doublenegative.com.au/jumpstart/examples/select/easyobject" rel="nofollow">Easy Object Select</a></p></div><p>Most commonly, your ValueEncoder's toClient() method will return a unique ID (e.g. a database primary key, or perhaps a UUID) of the given object, and its toValue() method will return the <em>object</em> matching the given ID by doing a database lookup (ideally using a service or DAO method).</p><p>If you're using one of the ORM integration modules (<a href="hibernate.html">Tapestry-Hibernate</a>, <a href="integrating-with-jpa.html">Tapestry-JPA</a>, or <a class="external-link" href="http://code.google.com/p/tapestry5-cayenne/wiki/ValueEncoder" rel="nofollow">Tapestry-Cayenne</a>), the ValueEncoder is automatically provided for each of your mapped entity classes. The Hibernate module's implementation is typical: the primary key field of the object (converted to a String) is used as the client-side value, and that same p
rimary key is used to look up the selected object.</p><p>That's exactly what you should do in your own ValueEncoders too:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeHeader panelHeader pdl" style="border-bottom-width: 1px;"><b>ColorEncoder.java (perhaps in your com.example.myappname.encoders package)</b></div><div class="codeContent panelContent pdl">
+<pre class="brush: java; gutter: false; theme: Default" style="font-size:12px;">public class ColorEncoder implements ValueEncoder<Color>, ValueEncoderFactory<Color> {
@Inject
private ColorService colorService;
@@ -116,7 +131,9 @@ public String toString() {
return this;
}
}
-</plain-text-body><p>Alternatively, if you don't expect to need a particular ValueEncoder more than once in your app, you might want to just create it on demand, using an anonymous inner class, from the getter method in the component class where it is needed. For example:</p><parameter ac:name="title">SelectWithListDemo.java (a page class, partial)</parameter><plain-text-body> . . .
+</pre>
+</div></div><p>Alternatively, if you don't expect to need a particular ValueEncoder more than once in your app, you might want to just create it on demand, using an anonymous inner class, from the getter method in the component class where it is needed. For example:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeHeader panelHeader pdl" style="border-bottom-width: 1px;"><b>SelectWithListDemo.java (a page class, partial)</b></div><div class="codeContent panelContent pdl">
+<pre class="brush: java; gutter: false; theme: Default" style="font-size:12px;"> . . .
public ValueEncoder<Color> getColorEncoder() {
@@ -135,26 +152,35 @@ public String toString() {
}
};
}
-</plain-text-body><p>Notice that the body of this anonymous inner class is the same as the body of the ColorEncoder top level class, except that we don't need a <code>create</code> method.</p><h2 id="UsingSelectWithaList-ApplyingyourValueEncoderAutomatically">Applying your ValueEncoder Automatically</h2><p>If your ValueEncoder <em>implements ValueEncoderFactory</em> (as the ColorEncoder top level class does, above), you can associate your custom ValueEncoder with your entity class so that Tapestry will automatically use it every time a ValueEncoder is needed for items of that type (such as with the Select, RadioGroup, Grid, Hidden and AjaxFormLoop components). Just add lines like the following to your module class (usually AppModule.java):</p><parameter ac:name="title">AppModule.java (partial)</parameter><plain-text-body>...
+</pre>
+</div></div><p>Notice that the body of this anonymous inner class is the same as the body of the ColorEncoder top level class, except that we don't need a <code>create</code> method.</p><h2 id="UsingSelectWithaList-ApplyingyourValueEncoderAutomatically">Applying your ValueEncoder Automatically</h2><p>If your ValueEncoder <em>implements ValueEncoderFactory</em> (as the ColorEncoder top level class does, above), you can associate your custom ValueEncoder with your entity class so that Tapestry will automatically use it every time a ValueEncoder is needed for items of that type (such as with the Select, RadioGroup, Grid, Hidden and AjaxFormLoop components). Just add lines like the following to your module class (usually AppModule.java):</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeHeader panelHeader pdl" style="border-bottom-width: 1px;"><b>AppModule.java (partial)</b></div><div class="codeContent panelContent pdl">
+<pre class="brush: java; gutter: false; theme: Default" style="font-size:12px;">...
public static void contributeValueEncoderSource(MappedConfiguration<Class<Color>,
ValueEncoderFactory<Color>> configuration) {
configuration.addInstance(Color.class, ColorEncoder.class);
}
-</plain-text-body><p>If you are contributing more than one ValueEncoder, you'll have to use raw types, like this:</p><parameter ac:name="title">AppModule.java (partial)</parameter><plain-text-body>...
+</pre>
+</div></div><p>If you are contributing more than one ValueEncoder, you'll have to use raw types, like this:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeHeader panelHeader pdl" style="border-bottom-width: 1px;"><b>AppModule.java (partial)</b></div><div class="codeContent panelContent pdl">
+<pre class="brush: java; gutter: false; theme: Default" style="font-size:12px;">...
public static void contributeValueEncoderSource(MappedConfiguration<Class,
ValueEncoderFactory> configuration)
{
configuration.addInstance(Color.class, ColorEncoder.class);
configuration.addInstance(SomeOtherType.class, SomeOtherTypeEncoder.class);
}
-</plain-text-body><h2 id="UsingSelectWithaList-WhatifIomittheValueEncoder?">What if I omit the ValueEncoder?</h2><p>The Select component's "encoder" parameter is optional, but if the "value" parameter is bound to a complex object (not a simple String, Integer, etc.) and you don't provide a ValueEncoder with the "encoder" parameter (and one isn't provided automatically by, for example, the Tapestry Hibernate integration), you'll receive a "Could not find a coercion" exception (when you submit the form) as Tapestry tries to convert the selected option's encoded value back to the <em>object</em> in your Select's "value" parameter. To fix this, you'll either have to 1) provide a ValueEncoder, 2) provide a <a href="type-coercion.html">Coercion</a>, or 3) use a simple value (String, Integer, etc.) for your Select's "value" parameter, and then you'll have to add logic in the corresponding onSuccess event listener method:</p><parameter ac:name="title">SelectWithListDemo.tml (partial)</para
meter><plain-text-body><t:select t:id="colorMenu" value="selectedColorId" model="ColorSelectModel" />
-</plain-text-body><parameter ac:name="title">SelectWithListDemo.java (partial)</parameter><plain-text-body>...
+</pre>
+</div></div><h2 id="UsingSelectWithaList-WhatifIomittheValueEncoder?">What if I omit the ValueEncoder?</h2><p>The Select component's "encoder" parameter is optional, but if the "value" parameter is bound to a complex object (not a simple String, Integer, etc.) and you don't provide a ValueEncoder with the "encoder" parameter (and one isn't provided automatically by, for example, the Tapestry Hibernate integration), you'll receive a "Could not find a coercion" exception (when you submit the form) as Tapestry tries to convert the selected option's encoded value back to the <em>object</em> in your Select's "value" parameter. To fix this, you'll either have to 1) provide a ValueEncoder, 2) provide a <a href="type-coercion.html">Coercion</a>, or 3) use a simple value (String, Integer, etc.) for your Select's "value" parameter, and then you'll have to add logic in the corresponding onSuccess event listener method:</p><div class="code panel pdl" style="border-width: 1px;"><div class="code
Header panelHeader pdl" style="border-bottom-width: 1px;"><b>SelectWithListDemo.tml (partial)</b></div><div class="codeContent panelContent pdl">
+<pre class="brush: java; gutter: false; theme: Default" style="font-size:12px;"><t:select t:id="colorMenu" value="selectedColorId" model="ColorSelectModel" />
+</pre>
+</div></div><div class="code panel pdl" style="border-width: 1px;"><div class="codeHeader panelHeader pdl" style="border-bottom-width: 1px;"><b>SelectWithListDemo.java (partial)</b></div><div class="codeContent panelContent pdl">
+<pre class="brush: java; gutter: false; theme: Default" style="font-size:12px;">...
public void onSuccessFromMyForm() {
// look up the color object from the ID selected
selectedColor = colorService.findById(selectedColorId);
...
}
-</plain-text-body><p>But then again, you may as well create a ValueEncoder instead.</p><h2 id="UsingSelectWithaList-Whyisthissohard?">Why is this so hard?</h2><p>Actually, it's really pretty easy if you follow the examples above. But why is Tapestry designed to use SelectModels and ValueEncoders anyway? Well, in short, this design allows you to avoid storing (via @Persist, @SessionAttribute or @SessionState) the entire (potentially large) list of objects in the session or rebuilding the whole list of objects again (though only one is needed) when the form is submitted. The chief benefits are reduced memory use and <a href="performance-and-clustering.html">more scalable clustering</a> due to having far less HTTP session data to replicate across the nodes of a cluster.</p></div>
+</pre>
+</div></div><p>But then again, you may as well create a ValueEncoder instead.</p><h2 id="UsingSelectWithaList-Whyisthissohard?">Why is this so hard?</h2><p>Actually, it's really pretty easy if you follow the examples above. But why is Tapestry designed to use SelectModels and ValueEncoders anyway? Well, in short, this design allows you to avoid storing (via @Persist, @SessionAttribute or @SessionState) the entire (potentially large) list of objects in the session or rebuilding the whole list of objects again (though only one is needed) when the form is submitted. The chief benefits are reduced memory use and <a href="performance-and-clustering.html">more scalable clustering</a> due to having far less HTTP session data to replicate across the nodes of a cluster.</p></div>
</div>
<div class="clearer"></div>
Modified: websites/production/tapestry/content/using-tapestry-with-hibernate.html
==============================================================================
--- websites/production/tapestry/content/using-tapestry-with-hibernate.html (original)
+++ websites/production/tapestry/content/using-tapestry-with-hibernate.html Wed Sep 20 12:29:16 2017
@@ -27,6 +27,15 @@
</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>
+ SyntaxHighlighter.defaults['toolbar'] = false;
+ SyntaxHighlighter.all();
+ </script>
<link href="/styles/style.css" rel="stylesheet" type="text/css"/>
@@ -36,26 +45,13 @@
<div class="wrapper bs">
- <div id="navigation"><div class="nav"><ul class="alternate"><li><a href="index.html">Home</a></li><li><a href="getting-started.html">Getting Started</a></li><li><a href="documentation.html">Documentation</a></li><li><a href="download.html">Download</a></li><li><a href="about.html">About</a></li><li><a class="external-link" href="http://www.apache.org/licenses/LICENSE-2.0">License</a></li><li><a href="community.html">Community</a></li><li><a class="external-link" href="http://www.apache.org/security/">Security</a></li><li><a class="external-link" href="http://www.apache.org/">Apache</a></li><li><a class="external-link" href="http://www.apache.org/foundation/sponsorship.html">Sponsorship</a></li><li><a class="external-link" href="http://www.apache.org/foundation/thanks.html">Thanks</a></li></ul></div>
-
-</div>
+ <div id="navigation"><div class="nav"><ul class="alternate"><li><a href="index.html">Home</a></li><li><a href="getting-started.html">Getting Started</a></li><li><a href="documentation.html">Documentation</a></li><li><a href="download.html">Download</a></li><li><a href="about.html">About</a></li><li><a class="external-link" href="http://www.apache.org/licenses/LICENSE-2.0">License</a></li><li><a href="community.html">Community</a></li><li><a class="external-link" href="http://www.apache.org/security/">Security</a></li><li><a class="external-link" href="http://www.apache.org/">Apache</a></li><li><a class="external-link" href="http://www.apache.org/foundation/sponsorship.html">Sponsorship</a></li><li><a class="external-link" href="http://www.apache.org/foundation/thanks.html">Thanks</a></li></ul></div></div>
<div id="top">
- <div id="smallbanner"><div class="searchbox" style="float:right;margin: .3em 1em .1em 1em"><span style="color: #999; font-size: 90%">Tapestry docs, issues, wikis & blogs:</span>
-<form enctype="application/x-www-form-urlencoded" method="get" action="http://tapestry.apache.org/search.html">
- <input type="text" name="q">
- <input type="submit" value="Search">
-</form>
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+</form></div><div class="emblem" style="float:left"><p><a href="index.html"><span class="confluence-embedded-file-wrapper"><img class="confluence-embedded-image confluence-external-resource" src="http://tapestry.apache.org/images/tapestry_small.png" data-image-src="http://tapestry.apache.org/images/tapestry_small.png"></span></a></p></div><div class="title" style="float:left; margin: 0 0 0 3em"><h1 id="SmallBanner-PageTitle">Using Tapestry With Hibernate</h1></div></div>
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@@ -67,7 +63,8 @@
</div>
<div id="content">
- <div id="ConfluenceContent"><p>So, you fill in all the fields, submit the form (without validation errors) and voila: you get back the same form, blanked out. What happened, and where did the data go?</p><p>What happened is that we haven't told Tapestry what to do after the form is successfully submitted (by successful, we mean, with no validation errors). Tapestry's default behavior is to redisplay the active page, and that occurs in a new request, with a new instance of the Address object (because the address field is not a peristent field).</p><p>Well, since we're creating objects, we might as well store them somewhere ... in a database. We're going to quickly integrate Tapestry with <a class="external-link" href="http://hibernate.org" rel="nofollow">Hibernate</a> as the object/relational mapping layer, and ultimately store our data inside a <a class="external-link" href="http://www.hsqldb.org/" rel="nofollow">HyperSQL</a> (HSQLDB) database. HSQLDB is an embedde
d database engine and requires no installation – it will be pulled down as a dependency by Maven.</p><h2 id="UsingTapestryWithHibernate-Re-configuringtheProject">Re-configuring the Project</h2><p>We're going to bootstrap this project from a simple Tapestry project to one that uses Hibernate and HSQLDB.</p><h3 id="UsingTapestryWithHibernate-UpdatingtheDependencies">Updating the Dependencies</h3><p>First, we must update the POM to list a new set of dependencies, that includes Hibernate, the Tapestry/Hibernate integration library, and the HSQLDB JDBC driver:</p><parameter ac:name="language">xml</parameter><parameter ac:name="title">src/pom.xml (partial)</parameter><plain-text-body> <dependencies>
+ <div id="ConfluenceContent"><p>So, you fill in all the fields, submit the form (without validation errors) and voila: you get back the same form, blanked out. What happened, and where did the data go?</p><p>What happened is that we haven't told Tapestry what to do after the form is successfully submitted (by successful, we mean, with no validation errors). Tapestry's default behavior is to redisplay the active page, and that occurs in a new request, with a new instance of the Address object (because the address field is not a peristent field).</p><p>Well, since we're creating objects, we might as well store them somewhere ... in a database. We're going to quickly integrate Tapestry with <a class="external-link" href="http://hibernate.org" rel="nofollow">Hibernate</a> as the object/relational mapping layer, and ultimately store our data inside a <a class="external-link" href="http://www.hsqldb.org/" rel="nofollow">HyperSQL</a> (HSQLDB) database. HSQLDB is an embedde
d database engine and requires no installation – it will be pulled down as a dependency by Maven.</p><h2 id="UsingTapestryWithHibernate-Re-configuringtheProject">Re-configuring the Project</h2><p>We're going to bootstrap this project from a simple Tapestry project to one that uses Hibernate and HSQLDB.</p><h3 id="UsingTapestryWithHibernate-UpdatingtheDependencies">Updating the Dependencies</h3><p>First, we must update the POM to list a new set of dependencies, that includes Hibernate, the Tapestry/Hibernate integration library, and the HSQLDB JDBC driver:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeHeader panelHeader pdl" style="border-bottom-width: 1px;"><b>src/pom.xml (partial)</b></div><div class="codeContent panelContent pdl">
+<pre class="brush: xml; gutter: false; theme: Default" style="font-size:12px;"> <dependencies>
<dependency>
<groupId>org.apache.tapestry</groupId>
@@ -82,7 +79,9 @@
</dependency>
...
</dependencies>
-</plain-text-body><p>The tapestry-hibernate library includes, as transitive dependencies, Hibernate and tapestry-core. This means that you can simply replace "tapestry-core" with "tapestry-hibernate" inside the <artifactId> element.</p><p>After changing the POM and saving, Maven should automatically download the JARs for the new dependencies.</p><h3 id="UsingTapestryWithHibernate-HibernateConfiguration">Hibernate Configuration</h3><p>Hibernate needs a master configuration file, hibernate.cfg.xml, used to store connection and other data. Create this in your src/main/resources folder:</p><parameter ac:name="language">xml</parameter><parameter ac:name="title">src/main/resources/hibernate.cfg.xml</parameter><plain-text-body><!DOCTYPE hibernate-configuration PUBLIC
+</pre>
+</div></div><p>The tapestry-hibernate library includes, as transitive dependencies, Hibernate and tapestry-core. This means that you can simply replace "tapestry-core" with "tapestry-hibernate" inside the <artifactId> element.</p><p>After changing the POM and saving, Maven should automatically download the JARs for the new dependencies.</p><h3 id="UsingTapestryWithHibernate-HibernateConfiguration">Hibernate Configuration</h3><p>Hibernate needs a master configuration file, hibernate.cfg.xml, used to store connection and other data. Create this in your src/main/resources folder:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeHeader panelHeader pdl" style="border-bottom-width: 1px;"><b>src/main/resources/hibernate.cfg.xml</b></div><div class="codeContent panelContent pdl">
+<pre class="brush: xml; gutter: false; theme: Default" style="font-size:12px;"><!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
@@ -97,7 +96,9 @@
<property name="hibernate.format_sql">true</property>
</session-factory>
</hibernate-configuration>
-</plain-text-body><p>Most of the configuration is to identify the JDBC driver and connection URL.</p><p>Note the connection URL. We are instructing HSQLDB to store its database files within our project's target directory. We are also instructing HSQLDB to flush any data to these files at shutdown. This means that data will persist across different invocations of this project, but if the target directory is destroyed (e.g., via "mvn clean"), then all the database contents will be lost.</p><p>In addition, we are configuring Hibernate to <em>update</em> the database schema; when Hibernate initializes it will create or even modify tables to match the entities. Finally, we are configuring Hibernate to output any SQL it executes, which is very useful when initially building an application.</p><p>But what entities? Normally, the available entities are listed inside hibernate.cfg.xml, but that's not necessary with Tapestry; in another example of convention over configuration, Tapestry locat
es all entity classes inside the entities package ("com.example.tutorial1.entities" in our case) and adds them to the configuration. Currently, that is just the Address entity.</p><h2 id="UsingTapestryWithHibernate-AddingHibernateAnnotations">Adding Hibernate Annotations</h2><p>For an entity class to be used with Hibernate, some Hibernate annotations must be added to the class.</p><p>Below is the updated Address class, with the Hibernate annotations (as well as the Tapestry ones).</p><parameter ac:name="language">java</parameter><parameter ac:name="title">src/main/java/com/example/tutorial/entities/Address.java</parameter><plain-text-body>package com.example.tutorial1.entities;
+</pre>
+</div></div><p>Most of the configuration is to identify the JDBC driver and connection URL.</p><p>Note the connection URL. We are instructing HSQLDB to store its database files within our project's target directory. We are also instructing HSQLDB to flush any data to these files at shutdown. This means that data will persist across different invocations of this project, but if the target directory is destroyed (e.g., via "mvn clean"), then all the database contents will be lost.</p><p>In addition, we are configuring Hibernate to <em>update</em> the database schema; when Hibernate initializes it will create or even modify tables to match the entities. Finally, we are configuring Hibernate to output any SQL it executes, which is very useful when initially building an application.</p><p>But what entities? Normally, the available entities are listed inside hibernate.cfg.xml, but that's not necessary with Tapestry; in another example of convention over configuration, Tapestry locates all
entity classes inside the entities package ("com.example.tutorial1.entities" in our case) and adds them to the configuration. Currently, that is just the Address entity.</p><h2 id="UsingTapestryWithHibernate-AddingHibernateAnnotations">Adding Hibernate Annotations</h2><p>For an entity class to be used with Hibernate, some Hibernate annotations must be added to the class.</p><p>Below is the updated Address class, with the Hibernate annotations (as well as the Tapestry ones).</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeHeader panelHeader pdl" style="border-bottom-width: 1px;"><b>src/main/java/com/example/tutorial/entities/Address.java</b></div><div class="codeContent panelContent pdl">
+<pre class="brush: java; gutter: false; theme: Default" style="font-size:12px;">package com.example.tutorial1.entities;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
@@ -142,7 +143,9 @@ public class Address
public String phone;
}
-</plain-text-body><p>The Tapestry annotations, @NonVisual and @Validate, may be placed on the setter or getter method or on the field (as we have done here). As with the Hibernate annotations, putting the annotation on the field requires that the field name match the corresponding property name.</p><ul><li><strong>@NonVisual</strong> – indicates a field, such as a primary key, that should not be made visible to the user.</li><li><strong>@Validate</strong> – identifies the validations associated with a field.</li></ul><p>At this point you should stop and restart your application.</p><h2 id="UsingTapestryWithHibernate-UpdatingtheDatabase">Updating the Database</h2><p>So we have a database set up, and Hibernate is configured to connect to it. Let's make use of that to store our Address object in the database.</p><p>What we need is to provide some code to be executed when the form is submitted. When a Tapestry form is submitted, there is a whole series of events that get fir
ed. The event we are interested in is the "success" event, which comes late in the process, after all the values have been pulled out of the request and applied to the page properties, and after all server-side validations have occurred.</p><p>The success event is only fired if there are no validation errors.</p><p>Our event handler must do two things:</p><ul><li>Use the Hibernate Session object to persist the new Address object.</li><li>Commit the transaction to force the data to be written to the database.</li></ul><p>Let's update our CreateAddress.java class:</p><parameter ac:name="language">java</parameter><parameter ac:name="title">src/main/java/com/example/tutorial/pages/address/CreateAddress.java</parameter><plain-text-body>package com.example.tutorial1.pages.address;
+</pre>
+</div></div><p>The Tapestry annotations, @NonVisual and @Validate, may be placed on the setter or getter method or on the field (as we have done here). As with the Hibernate annotations, putting the annotation on the field requires that the field name match the corresponding property name.</p><ul><li><strong>@NonVisual</strong> – indicates a field, such as a primary key, that should not be made visible to the user.</li><li><strong>@Validate</strong> – identifies the validations associated with a field.</li></ul><p>At this point you should stop and restart your application.</p><h2 id="UsingTapestryWithHibernate-UpdatingtheDatabase">Updating the Database</h2><p>So we have a database set up, and Hibernate is configured to connect to it. Let's make use of that to store our Address object in the database.</p><p>What we need is to provide some code to be executed when the form is submitted. When a Tapestry form is submitted, there is a whole series of events that get fired. Th
e event we are interested in is the "success" event, which comes late in the process, after all the values have been pulled out of the request and applied to the page properties, and after all server-side validations have occurred.</p><p>The success event is only fired if there are no validation errors.</p><p>Our event handler must do two things:</p><ul><li>Use the Hibernate Session object to persist the new Address object.</li><li>Commit the transaction to force the data to be written to the database.</li></ul><p>Let's update our CreateAddress.java class:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeHeader panelHeader pdl" style="border-bottom-width: 1px;"><b>src/main/java/com/example/tutorial/pages/address/CreateAddress.java</b></div><div class="codeContent panelContent pdl">
+<pre class="brush: java; gutter: false; theme: Default" style="font-size:12px;">package com.example.tutorial1.pages.address;
import com.example.tutorial1.entities.Address;
import com.example.tutorial1.pages.Index;
@@ -171,9 +174,13 @@ public class CreateAddress
return index;
}
}
-</plain-text-body><p>The <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/annotations/Inject.html">Inject</a> annotation tells Tapestry to inject a service into the annotated field; Tapestry includes a sophisticated Inversion of Control container (similar in many ways to Spring) that is very good at locating available services by type, rather than by a string id. In any case, the Hibernate Session object is exposed as a Tapestry IoC service, ready to be injected (this is one of the things provided by the tapestry-hibernate module).</p><p>Tapestry automatically starts a transaction as necessary; however that transaction will be <em>aborted</em> at the end of the request by default. If we make changes to persistent objects, such as adding a new Address object, then it is necessary to commit the transaction.</p><p>The <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/hibernate/annotations/C
ommitAfter.html">CommitAfter</a> annotation can be applied to any component method; if the method completes normally, the transaction will be committed (and a new transaction started to replace the committed transaction).</p><p>After persisting the new address, we return to the main Index page of the application.</p><p><em>Note: In real applications, it is rare to have pages and components directly use the Hibernate Session. It is generally a better approach to define your own Data Access Object layer to perform common update operations and queries.</em></p><h2 id="UsingTapestryWithHibernate-ShowingAddresses">Showing Addresses</h2><p>As a little preview of what's next, let's display all the Addresses entered by the user on the Index page of the application. After you enter a few names, it will look something like:</p><p><span class="confluence-embedded-file-wrapper"><img class="confluence-embedded-image confluence-content-image-border" src="using-tapestry-with-hibernate.data/index-g
rid-v1.png"></span></p><h2 id="UsingTapestryWithHibernate-AddingtheGridtotheIndexpage">Adding the Grid to the Index page</h2><p>So, how is this implemented? Primarily, its accomplished by the <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/corelib/components/Grid.html">Grid</a> component.</p><p>The Grid component is based on the same concepts as the BeanEditForm component; it can pull apart a bean into columns. The columns are sortable, and when there are more entries than will fit on a single page, page navigation is automatically added.</p><p>A minimal Grid is very easy to add to the template. Just add this near the bottom of Index.tml:</p><parameter ac:name="language">xml</parameter><parameter ac:name="title">src/main/webapp/Index.tml (partial)</parameter><plain-text-body> <t:grid source="addresses"
+</pre>
+</div></div><p>The <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/annotations/Inject.html">Inject</a> annotation tells Tapestry to inject a service into the annotated field; Tapestry includes a sophisticated Inversion of Control container (similar in many ways to Spring) that is very good at locating available services by type, rather than by a string id. In any case, the Hibernate Session object is exposed as a Tapestry IoC service, ready to be injected (this is one of the things provided by the tapestry-hibernate module).</p><p>Tapestry automatically starts a transaction as necessary; however that transaction will be <em>aborted</em> at the end of the request by default. If we make changes to persistent objects, such as adding a new Address object, then it is necessary to commit the transaction.</p><p>The <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/hibernate/annotations/CommitA
fter.html">CommitAfter</a> annotation can be applied to any component method; if the method completes normally, the transaction will be committed (and a new transaction started to replace the committed transaction).</p><p>After persisting the new address, we return to the main Index page of the application.</p><p><em>Note: In real applications, it is rare to have pages and components directly use the Hibernate Session. It is generally a better approach to define your own Data Access Object layer to perform common update operations and queries.</em></p><h2 id="UsingTapestryWithHibernate-ShowingAddresses">Showing Addresses</h2><p>As a little preview of what's next, let's display all the Addresses entered by the user on the Index page of the application. After you enter a few names, it will look something like:</p><p><span class="confluence-embedded-file-wrapper"><img class="confluence-embedded-image confluence-content-image-border" src="using-tapestry-with-hibernate.data/index-grid-v1
.png"></span></p><h2 id="UsingTapestryWithHibernate-AddingtheGridtotheIndexpage">Adding the Grid to the Index page</h2><p>So, how is this implemented? Primarily, its accomplished by the <a class="external-link" href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/corelib/components/Grid.html">Grid</a> component.</p><p>The Grid component is based on the same concepts as the BeanEditForm component; it can pull apart a bean into columns. The columns are sortable, and when there are more entries than will fit on a single page, page navigation is automatically added.</p><p>A minimal Grid is very easy to add to the template. Just add this near the bottom of Index.tml:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeHeader panelHeader pdl" style="border-bottom-width: 1px;"><b>src/main/webapp/Index.tml (partial)</b></div><div class="codeContent panelContent pdl">
+<pre class="brush: xml; gutter: false; theme: Default" style="font-size:12px;"> <t:grid source="addresses"
include="honorific,firstName,lastName,street1,city,state,zip,phone"/>
-</plain-text-body><p>Note that the Grid component accepts many of the same parameters that we used with the BeanEditForm. Here we use the include parameter to specify the properties to show, and in what order.</p><p>Now all we have to do is supply the addresses property in the Java code. Here's how Index.java should look now:</p><parameter ac:name="language">java</parameter><parameter ac:name="title">src/main/java/com/example/tutorial/pages/Index.java</parameter><plain-text-body>package com.example.tutorial1.pages;
+</pre>
+</div></div><p>Note that the Grid component accepts many of the same parameters that we used with the BeanEditForm. Here we use the include parameter to specify the properties to show, and in what order.</p><p>Now all we have to do is supply the addresses property in the Java code. Here's how Index.java should look now:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeHeader panelHeader pdl" style="border-bottom-width: 1px;"><b>src/main/java/com/example/tutorial/pages/Index.java</b></div><div class="codeContent panelContent pdl">
+<pre class="brush: java; gutter: false; theme: Default" style="font-size:12px;">package com.example.tutorial1.pages;
import java.util.List;
import org.apache.tapestry5.ioc.annotations.Inject;
import org.hibernate.Session;
@@ -187,7 +194,8 @@ public class Index
return session.createCriteria(Address.class).list();
}
}
-</plain-text-body><p>Here, we're using the Hibernate Session object to find all Address objects in the database. Any sorting that takes place will be done in memory. This is fine for now (with only a handful of Address objects in the database). Later we'll see how to optimize this for very large result sets.</p><h2 id="UsingTapestryWithHibernate-What'sNext?">What's Next?</h2><p>We have lots more to talk about: more components, more customizations, built-in Ajax support, more common design and implementation patterns, and even writing your own components (which is easy!).</p><p>Check out the many Tapestry resources available on the <a href="documentation.html">Documentation</a> page, including the <a href="getting-started.html">Getting Started</a> and <a href="frequently-asked-questions.html">FAQ</a> pages and the <a href="cookbook.html">Cookbook</a>. Be sure to peruse the <a href="user-guide.html">User Guide</a>, which provides comprehensive details on nearly every Tapestry top
ic. Finally, be sure to visit (and bookmark) <a class="external-link" href="http://jumpstart.doublenegative.com.au/jumpstart7/" rel="nofollow">Tapestry JumpStart</a>, which provides a nearly exhaustive set of tutorials.</p><p> </p><p></p></div>
+</pre>
+</div></div><p>Here, we're using the Hibernate Session object to find all Address objects in the database. Any sorting that takes place will be done in memory. This is fine for now (with only a handful of Address objects in the database). Later we'll see how to optimize this for very large result sets.</p><h2 id="UsingTapestryWithHibernate-What'sNext?">What's Next?</h2><p>We have lots more to talk about: more components, more customizations, built-in Ajax support, more common design and implementation patterns, and even writing your own components (which is easy!).</p><p>Check out the many Tapestry resources available on the <a href="documentation.html">Documentation</a> page, including the <a href="getting-started.html">Getting Started</a> and <a href="frequently-asked-questions.html">FAQ</a> pages and the <a href="cookbook.html">Cookbook</a>. Be sure to peruse the <a href="user-guide.html">User Guide</a>, which provides comprehensive details on nearly every Tapestry topic. Fi
nally, be sure to visit (and bookmark) <a class="external-link" href="http://jumpstart.doublenegative.com.au/jumpstart7/" rel="nofollow">Tapestry JumpStart</a>, which provides a nearly exhaustive set of tutorials.</p><p> </p><p></p></div>
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