doc/src/ComponentReference/DirectLink.html - tapestry3 - Git at Google

 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
 <!-- $Id$ -->
 <html>
 <head>
 <title>DirectLink</title>
 <link rel="stylesheet" type="text/css" href="Tapestry.css" title="style">
 </head>

 <body>
 <table border="0" cellpadding="0" cellspacing="0" width="100%">
  <tr>
   <td align="left"><A href="Delegator.html"><IMG alt=Delegator src="common-images/prev.png"></A></td>
   <td align="middle"><A href="index.html"><IMG alt="Component Index" src="common-images/home.png" ></A></td>
   <td align="right"><A href="ExceptionDisplay.html"><IMG alt=ExceptionDisplay src="common-images/next.png"></A></td>
  <tr>
  <tr>
   <td colspan="3"><hr></td>
  </tr>
  <tr>
   <td colspan="3">
    <table border="0" cellpadding="4" cellspacing="4" width="100%">

 <tr valign="top">
  <td>
   <table>
 	 <tr>
 	  <td><font size="+2"><b>DirectLink</b></font></td>
 	 </tr>
 	 <tr>
 	  <td>
 		 <A href="../api/org/apache/tapestry/link/DirectLink.html">
 		 org.apache.tapestry.link.DirectLink</A>
 		</td>
 	 </tr>
   </table>
  </td>
  <td>
   <table align="right" valign="middle" bgcolor="#c0c0c0" cellpadding="8">
 	 <tr>
 	  <td><A href="DirectLink.html"><font color="blue">Direct Link</font></A></td>
 	 </tr>
   </table>
  </td>
 </tr>

 <tr valign="center">
  <td colspan="2">&nbsp;</td>
 </tr>

 <tr>
  <td colspan="2">
   <b>Description</b>
 	<br>
   Creates a &lt;a&gt; hyperlink that notifies the component when the link is
   triggered. The link includes some context-specific data that is made available
   to the component's listener. This is used in cases where the
   <a href="ActionLink.html">ActionLink</a> component can't be used (or is too inefficient).
   <p>
   See the Developers Guide <A href="../DevelopersGuide/cycle.listeners.html">
   ActionLink and DirectLink listeners</A> for a more complete description.</p>
             <P>Prior to release 2.2, this component was named
             <STRONG>Direct</STRONG>.</P>

  </td>
 </tr>

 <tr>
  <td colspan="2">
   <b>See Also</b>
 	<br>
 	<a href="ActionLink.html">ActionLink</a>,
 	<A href="ExternalLink.html">ExternalLink</a>,
   <A href="GenericLink.html">GenericLink</A>,
   <a href="PageLink.html">PageLink</a>,
   <a href="ServiceLink.html">ServiceLink</a>
  </td>
 </tr>

 <tr>
  <td colspan="2">
   <b>Parameters</b>
 	<br>
   <table border="1" cellpadding="4" cellspacing="4" class="parameters">
   <tr>
     <th>Name</th>
     <th>Type</th>
 	  <th>Direction</th>
     <th>Required</th>
     <th>Default</th>
     <th>Description</th>
   </tr>
   <tr>
     <td>listener</td>
     <td>
      <A href="../api/org/apache/tapestry/IActionListener.html"><tt>IActionListener</tt></A>
     </td>
     <td>in</td>
    	<td>yes</td>
 		<td>&nbsp;</td>
 		<td>Specifies an object that is notified when the link is clicked,
 		which is typically a listener method of its container
 		(for example, <tt>listeners.<i>method</i></tt>).</td>
 	</tr>
   <tr>
     <td>parameters</td>
     <td>Object or<br>
         Object[] or<br>
      <a href="http://java.sun.com/products/jdk/1.2/docs/api/java/util/List.html">
      <tt>List</tt></a>
     </td>
     <td>in</td>
    	<td>no</td>
 		<td>&nbsp;</td>
 		<td>
     An array of objects to be encoded into the URL. These parameters will be
     decoded when the link is triggered.
     <p>
     In a web application built onto of Enterprise JavaBeans, the context is
     often the primary key of some Entity bean; typically such keys are Strings
     or Integers.
     <p>
     A listener method can retrieve the parameters using
     <A href="../api/org/apache/tapestry/IRequestCycle.html#getServiceParameters()">
     <tt>IRequestCycle.getServiceParameters()</tt></A>.
     <p>
     Prior to release 2.2, the parameters were always type String. They may now
     be of any type; type will be maintained when the parameters are later
     retrieved by a listener. See
     <A href="../api/org/apache/tapestry/util/io/DataSqueezer.html"><tt>DataSqueezer</tt></A> for more details.</p>

     </td>
 	</tr>
   <tr>
     <td>disabled</td>
     <td>boolean</td>
     <td>in</td>
    	<td>no</td>
 		<td>false</td>
 		<td>Controls whether the link is produced. If disabled, the portion of the
     template the link surrounds is still rendered, but not the link itself.
     </td>
 	</tr>
   <tr>
     <td>stateful</td>
     <td>boolean</td>
     <td>in</td>
    	<td>no</td>
 		<td>true</td>
 		<td>
     If true (the default), then the component requires an active (i.e., non-new)
     <tt>HttpSession</tt> when triggered. Failing that, it throws a
     <A href="../api/org/apache/tapestry/StaleLinkException"><tt>StaleLinkException</tt></A>.
     If false, then no check is necessary. The
     latter works well with links that encode all necessary state inside the URL
     itself.
     </td>
 	</tr>

   <tr>
     <td>anchor</td>
     <td>String</td>
     <td>in</td>
    	<td>no</td>
 		<td>&nbsp;</td>
 		<td>
     The name of an anchor or element to link to. The final URL will have '#'
     and the anchor appended to it.
     </td>
 	</tr>
 	<tr>
 		<td>renderer</td>
 		<td><a href="../api/org/apache/tapestry/link/ILinkRenderer.html">ILinkRenderer</a></td>
 		<td>in</td>
 		<td>no</td>
 		<td>&nbsp;</td>
 		<td>
 		The object which will actually render the link.
 			</td>
 	</tr>
 	</table>
             <P>Body: <STRONG>rendered</STRONG><BR>Informal parameters:
             <STRONG>allowed</STRONG>
     <br>
   Reserved parameters:
             "href" </P>

  </td>
 </tr>

 <tr>
  <td colspan="2">
   <b>Examples</b>
 	<p>
   In this example the DirectLink component enables users to select or delete
   Customers from a Customer List table.
 	<p>

 <table class="tapestry-examples" cellspacing="6">
   <tr align="left">
    <th>ID</th>
    <th>&nbsp;</th>
    <th>Name</th>
    <th>&nbsp;</th>
    <th>Level</th>
    <th>&nbsp;</th>
   </tr>
   <tr>
    <td colspan="6"><hr></td>
   </tr>
   <tr>
    <td>10276</td>
    <td>&nbsp;</td>
    <td><a href="DirectLink.html" style="{color:blue;}">Ms Sophie L. Jamies</a></td>
    <td>&nbsp;</td>
    <td>Platinum</td>
    <td><a href="DirectLink.html" style="{color:blue;}"><img src="images/delete.gif" alt="Delete"></a></td>
   </tr>
   <tr>
    <td>10539</td>
    <td>&nbsp;</td>
    <td><a href="DirectLink.html" style="{color:blue;}">Mr Albert H. Davies</a></td>
    <td>&nbsp;</td>
    <td>Gold</td>
    <td><a href="DirectLink.html" style="{color:blue;}"><img src="images/delete.gif" alt="Delete"></a></td>
   </tr>
   <tr>
    <td>10552</td>
    <td>&nbsp;</td>
    <td><a href="DirectLink.html" style="{color:blue;}">Mrs Jan S. Flawson</a></td>
    <td>&nbsp;</td>
    <td>Gold</td>
    <td><a href="DirectLink.html" style="{color:blue;}"><img src="images/delete.gif" alt="Delete"></a></td>
   </tr>
   <tr>
    <td>10863</td>
    <td>&nbsp;</td>
    <td><a href="DirectLink.html" style="{color:blue;}">Mr Robert J. Hassel</a></td>
    <td>&nbsp;</td>
    <td>Silver</td>
    <td><a href="DirectLink.html" style="{color:blue;}"><img src="images/delete.gif" alt="Delete"></a></td>
   </tr>
 </table>

             <pre>
 &lt;table cellspacing="6"&gt;
   &lt;tr&gt;
    &lt;td&gt;ID&lt;/td&gt;
    &lt;td&gt;&amp;nbsp;&lt;/td&gt;
    &lt;td&gt;Name&lt;/td&gt;
    &lt;td&gt;&amp;nbsp;&lt;/td&gt;
    &lt;td&gt;Level&lt;/td&gt;
    &lt;td&gt;&amp;nbsp;&lt;/td&gt;
   &lt;/tr&gt;
   &lt;tr&gt;
    &lt;td colspan="6"&gt;&lt;hr&gt;&lt;/td&gt;
   &lt;/tr&gt;
   &lt;tr jwcid="@<a href="Foreach.html">Foreach</a>" source="ognl:visit.customerList" value="ognl:customer" element=&quot;tr&quot;&gt;
    &lt;td&gt;&lt;span jwcid="@<a href="Insert.html">Insert</a>" value="ognl:customer.id"/&gt;&lt;/td&gt;
    &lt;td&gt;&amp;nbsp;&lt;/td&gt;
    &lt;td&gt;&lt;a jwcid="<span class="jwcid">@<a href="DirectLink.html">DirectLink</a></span>" listener="ognl:listeners.customerSelectAction" parameters="ognl:customer.id"&gt; &lt;span jwcid="@<a href="Insert.html">Insert</a>" value="ognl:customer.fullName"/&gt; &lt;/a&gt;&lt;/td&gt;
    &lt;td&gt;&amp;nbsp;&lt;/td&gt;
    &lt;td&gt;&lt;span jwcid="@<a href="Insert.html">Insert</a>" value="ognl:customer.memberLevel"/&gt;&lt;/td&gt;
    &lt;td&gt;
     &lt;a jwcid="<span class="jwcid">@<a href="DirectLink.html">DirectLink</a></span>" listener="ognl:listeners.customerDeleteAction" parameters="ognl:customer.id" onclick="return window.confirm('Are you sure you want remove this customer?');"&gt;
      &lt;img jwcid="@<a href="Image.html">Image</a>" image="ognl:assets.deleteImage" alt="Delete"/&gt;
     &lt;/a&gt;
    &lt;/td&gt;
   &lt;/tr&gt;
 &lt;/table&gt;


 &lt;property-specification name=&quot;customer&quot; type=&quot;com.mycorp.Customer&quot;/&gt;<br>&lt;private-asset name="deleteImage" resource-path="/com/mycorp/delete.gif"/&gt;


 package com.mycorp;

 public abstract class SalesPage extends BasePage {
     public void customerSelectAction(IRequestCycle cycle) {
         Visit visit = (Visit) getVisit();
         Object[] parameters = cycle.getServiceParameters();
         Customer customer = visit.findCustomerByPrimaryKey((Integer) parameters[0]);
         // Perform some action with the selected customer.
         ..
     }

     public void customerDeleteAction(IRequestCycle cycle) {
         Visit visit = (Visit) getVisit();
         Object[] parameters = cycle.getServiceParameters();
         Customer customer = visit.findCustomerByPrimaryKey((Integer) parameters[0]);
         visit.deleteCustomer(customer);
     }
 }

 public class Visit() implements Serializable {

     public List getCustomerList() {
         List customerList = new ArrayList();
         // Perform a database query retrieving the list of customers.
         ..
         return customerList;
     }

     public Customer findCustomerByPrimaryKey(Integer id) {
         Customer customer = null;
         // Retrieve the customer from the database with given the customer ID.
         ..
         return customer;
     }

     public void deleteCustomer(Customer customer) {
         // Delete customer from the database.
         ..
     }
 }

 public class Customer implements Serializable {
     private Integer id;
     private String fullName;
     private String memberLevel;

     public Customer(Integer id, String fullName, String memberLevel) {
         this.id = id;
         this.fullName = fullName;
         this.memberLevel = memberLevel;
     }

     public Integer getId() { return id; }

     public String getFullName() { return fullName; }

     public String getMemberLevel() { return memberLevel; }
 }
 </pre>
           </td>
         </tr></table>
 </td></tr>
 <tr>
  <td colspan="3"><hr></td>
 </tr>
 <tr>
  <td align="left"><A href="Delegator.html"><IMG alt=Delegator src="common-images/prev.png"></A></td>
  <td align="middle"><A href="index.html"><IMG alt="Component Index" src="common-images/home.png" ></A></td>
  <td align="right"><A href="ExceptionDisplay.html"><IMG alt=ExceptionDisplay src="common-images/next.png"></A></td>
 </tr>
 </table>

 </body>
 </html>
	<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
	<!-- $Id$ -->
	<html>
	<head>
	<title>DirectLink</title>
	<link rel="stylesheet" type="text/css" href="Tapestry.css" title="style">
	</head>

	<body>
	<table border="0" cellpadding="0" cellspacing="0" width="100%">
	<tr>
	<td align="left"><A href="Delegator.html"><IMG alt=Delegator src="common-images/prev.png"></A></td>
	<td align="middle"><A href="index.html"><IMG alt="Component Index" src="common-images/home.png" ></A></td>
	<td align="right"><A href="ExceptionDisplay.html"><IMG alt=ExceptionDisplay src="common-images/next.png"></A></td>
	<tr>
	<tr>
	<td colspan="3"><hr></td>
	</tr>
	<tr>
	<td colspan="3">
	<table border="0" cellpadding="4" cellspacing="4" width="100%">

	<tr valign="top">
	<td>
	<table>
	<tr>
	<td><font size="+2"><b>DirectLink</b></font></td>
	</tr>
	<tr>
	<td>
	<A href="../api/org/apache/tapestry/link/DirectLink.html">
	org.apache.tapestry.link.DirectLink</A>
	</td>
	</tr>
	</table>
	</td>
	<td>
	<table align="right" valign="middle" bgcolor="#c0c0c0" cellpadding="8">
	<tr>
	<td><A href="DirectLink.html"><font color="blue">Direct Link</font></A></td>
	</tr>
	</table>
	</td>
	</tr>

	<tr valign="center">
	<td colspan="2"> </td>
	</tr>

	<tr>
	<td colspan="2">
	<b>Description</b>
	<br>
	Creates a <a> hyperlink that notifies the component when the link is
	triggered. The link includes some context-specific data that is made available
	to the component's listener. This is used in cases where the
	<a href="ActionLink.html">ActionLink</a> component can't be used (or is too inefficient).
	<p>
	See the Developers Guide <A href="../DevelopersGuide/cycle.listeners.html">
	ActionLink and DirectLink listeners</A> for a more complete description.</p>
	<P>Prior to release 2.2, this component was named
	<STRONG>Direct</STRONG>.</P>

	</td>
	</tr>

	<tr>
	<td colspan="2">
	<b>See Also</b>
	<br>
	<a href="ActionLink.html">ActionLink</a>,
	<A href="ExternalLink.html">ExternalLink</a>,
	<A href="GenericLink.html">GenericLink</A>,
	<a href="PageLink.html">PageLink</a>,
	<a href="ServiceLink.html">ServiceLink</a>
	</td>
	</tr>

	<tr>
	<td colspan="2">
	<b>Parameters</b>
	<br>
	<table border="1" cellpadding="4" cellspacing="4" class="parameters">
	<tr>
	<th>Name</th>
	<th>Type</th>
	<th>Direction</th>
	<th>Required</th>
	<th>Default</th>
	<th>Description</th>
	</tr>
	<tr>
	<td>listener</td>
	<td>
	<A href="../api/org/apache/tapestry/IActionListener.html"><tt>IActionListener</tt></A>
	</td>
	<td>in</td>
	<td>yes</td>
	<td> </td>
	<td>Specifies an object that is notified when the link is clicked,
	which is typically a listener method of its container
	(for example, <tt>listeners.<i>method</i></tt>).</td>
	</tr>
	<tr>
	<td>parameters</td>
	<td>Object or<br>
	Object[] or<br>
	<a href="http://java.sun.com/products/jdk/1.2/docs/api/java/util/List.html">
	<tt>List</tt></a>
	</td>
	<td>in</td>
	<td>no</td>
	<td> </td>
	<td>
	An array of objects to be encoded into the URL. These parameters will be
	decoded when the link is triggered.
	<p>
	In a web application built onto of Enterprise JavaBeans, the context is
	often the primary key of some Entity bean; typically such keys are Strings
	or Integers.
	<p>
	A listener method can retrieve the parameters using
	<A href="../api/org/apache/tapestry/IRequestCycle.html#getServiceParameters()">
	<tt>IRequestCycle.getServiceParameters()</tt></A>.
	<p>
	Prior to release 2.2, the parameters were always type String. They may now
	be of any type; type will be maintained when the parameters are later
	retrieved by a listener. See
	<A href="../api/org/apache/tapestry/util/io/DataSqueezer.html"><tt>DataSqueezer</tt></A> for more details.</p>

	</td>
	</tr>
	<tr>
	<td>disabled</td>
	<td>boolean</td>
	<td>in</td>
	<td>no</td>
	<td>false</td>
	<td>Controls whether the link is produced. If disabled, the portion of the
	template the link surrounds is still rendered, but not the link itself.
	</td>
	</tr>
	<tr>
	<td>stateful</td>
	<td>boolean</td>
	<td>in</td>
	<td>no</td>
	<td>true</td>
	<td>
	If true (the default), then the component requires an active (i.e., non-new)
	<tt>HttpSession</tt> when triggered. Failing that, it throws a
	<A href="../api/org/apache/tapestry/StaleLinkException"><tt>StaleLinkException</tt></A>.
	If false, then no check is necessary. The
	latter works well with links that encode all necessary state inside the URL
	itself.
	</td>
	</tr>

	<tr>
	<td>anchor</td>
	<td>String</td>
	<td>in</td>
	<td>no</td>
	<td> </td>
	<td>
	The name of an anchor or element to link to. The final URL will have '#'
	and the anchor appended to it.
	</td>
	</tr>
	<tr>
	<td>renderer</td>
	<td><a href="../api/org/apache/tapestry/link/ILinkRenderer.html">ILinkRenderer</a></td>
	<td>in</td>
	<td>no</td>
	<td> </td>
	<td>
	The object which will actually render the link.
	</td>
	</tr>
	</table>
	<P>Body: <STRONG>rendered</STRONG><BR>Informal parameters:
	<STRONG>allowed</STRONG>
	<br>
	Reserved parameters:
	"href" </P>

	</td>
	</tr>

	<tr>
	<td colspan="2">
	<b>Examples</b>
	<p>
	In this example the DirectLink component enables users to select or delete
	Customers from a Customer List table.
	<p>

	<table class="tapestry-examples" cellspacing="6">
	<tr align="left">
	<th>ID</th>
	<th> </th>
	<th>Name</th>
	<th> </th>
	<th>Level</th>
	<th> </th>
	</tr>
	<tr>
	<td colspan="6"><hr></td>
	</tr>
	<tr>
	<td>10276</td>
	<td> </td>
	<td><a href="DirectLink.html" style="{color:blue;}">Ms Sophie L. Jamies</a></td>
	<td> </td>
	<td>Platinum</td>
	<td><a href="DirectLink.html" style="{color:blue;}"><img src="images/delete.gif" alt="Delete"></a></td>
	</tr>
	<tr>
	<td>10539</td>
	<td> </td>
	<td><a href="DirectLink.html" style="{color:blue;}">Mr Albert H. Davies</a></td>
	<td> </td>
	<td>Gold</td>
	<td><a href="DirectLink.html" style="{color:blue;}"><img src="images/delete.gif" alt="Delete"></a></td>
	</tr>
	<tr>
	<td>10552</td>
	<td> </td>
	<td><a href="DirectLink.html" style="{color:blue;}">Mrs Jan S. Flawson</a></td>
	<td> </td>
	<td>Gold</td>
	<td><a href="DirectLink.html" style="{color:blue;}"><img src="images/delete.gif" alt="Delete"></a></td>
	</tr>
	<tr>
	<td>10863</td>
	<td> </td>
	<td><a href="DirectLink.html" style="{color:blue;}">Mr Robert J. Hassel</a></td>
	<td> </td>
	<td>Silver</td>
	<td><a href="DirectLink.html" style="{color:blue;}"><img src="images/delete.gif" alt="Delete"></a></td>
	</tr>
	</table>

	<pre>
	<table cellspacing="6">
	<tr>
	<td>ID</td>
	<td>&nbsp;</td>
	<td>Name</td>
	<td>&nbsp;</td>
	<td>Level</td>
	<td>&nbsp;</td>
	</tr>
	<tr>
	<td colspan="6"><hr></td>
	</tr>
	<tr jwcid="@<a href="Foreach.html">Foreach</a>" source="ognl:visit.customerList" value="ognl:customer" element="tr">
	<td><span jwcid="@<a href="Insert.html">Insert</a>" value="ognl:customer.id"/></td>
	<td>&nbsp;</td>
	<td><a jwcid="<span class="jwcid">@<a href="DirectLink.html">DirectLink</a></span>" listener="ognl:listeners.customerSelectAction" parameters="ognl:customer.id"> <span jwcid="@<a href="Insert.html">Insert</a>" value="ognl:customer.fullName"/> </a></td>
	<td>&nbsp;</td>
	<td><span jwcid="@<a href="Insert.html">Insert</a>" value="ognl:customer.memberLevel"/></td>
	<td>
	<a jwcid="<span class="jwcid">@<a href="DirectLink.html">DirectLink</a></span>" listener="ognl:listeners.customerDeleteAction" parameters="ognl:customer.id" onclick="return window.confirm('Are you sure you want remove this customer?');">
	<img jwcid="@<a href="Image.html">Image</a>" image="ognl:assets.deleteImage" alt="Delete"/>
	</a>
	</td>
	</tr>
	</table>


	<property-specification name="customer" type="com.mycorp.Customer"/><br><private-asset name="deleteImage" resource-path="/com/mycorp/delete.gif"/>


	package com.mycorp;

	public abstract class SalesPage extends BasePage {
	public void customerSelectAction(IRequestCycle cycle) {
	Visit visit = (Visit) getVisit();
	Object[] parameters = cycle.getServiceParameters();
	Customer customer = visit.findCustomerByPrimaryKey((Integer) parameters[0]);
	// Perform some action with the selected customer.
	..
	}

	public void customerDeleteAction(IRequestCycle cycle) {
	Visit visit = (Visit) getVisit();
	Object[] parameters = cycle.getServiceParameters();
	Customer customer = visit.findCustomerByPrimaryKey((Integer) parameters[0]);
	visit.deleteCustomer(customer);
	}
	}

	public class Visit() implements Serializable {

	public List getCustomerList() {
	List customerList = new ArrayList();
	// Perform a database query retrieving the list of customers.
	..
	return customerList;
	}

	public Customer findCustomerByPrimaryKey(Integer id) {
	Customer customer = null;
	// Retrieve the customer from the database with given the customer ID.
	..
	return customer;
	}

	public void deleteCustomer(Customer customer) {
	// Delete customer from the database.
	..
	}
	}

	public class Customer implements Serializable {
	private Integer id;
	private String fullName;
	private String memberLevel;

	public Customer(Integer id, String fullName, String memberLevel) {
	this.id = id;
	this.fullName = fullName;
	this.memberLevel = memberLevel;
	}

	public Integer getId() { return id; }

	public String getFullName() { return fullName; }

	public String getMemberLevel() { return memberLevel; }
	}
	</pre>
	</td>
	</tr></table>
	</td></tr>
	<tr>
	<td colspan="3"><hr></td>
	</tr>
	<tr>
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