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 <h1 class="topictitle1">Creating Listeners</h1>

 <div>
 <p>The listener wizard helps you create application lifecycle
 listeners by walking you through the creation process and by providing
 you with output files that you can use or that you can modify for use
 with your Web application. The listeners can run on Java EE-compliant
 Web servers.</p>

 <div class="section">
 <p>To create a listener, complete the following steps:</p>
 </div>

 <ol>
 	<li class="stepexpand"><span>In the Java EE perspective,
 	expand your <a href="ccwebprj.html" title="">dynamic project</a> in the
 	Project Explorer view.</span></li>

 	<li class="stepexpand"><span>Right click on the <strong>Listener</strong>
 	icon, and select <span class="menucascade"> <span
 		class="uicontrol">New</span> &gt; <span class="uicontrol">Listener</span></span>
 	from the pop-up menu.</span> The <span class="uicontrol">Create Listener</span>
 	wizard appears.</li>

 	<li class="stepexpand"><span>Follow the project wizard
 	prompts.</span></li>

 </ol>

 <div class="section">
 <p><strong>General Information</strong></p>
 <dl>

 	<p>
 	<dt class="dlterm">Application lifecycle listeners</dt>
 	</p>

 	<dd>The <cite>Sun Microsystems Java Servlet Specification</cite> defines the
 	following interfaces that represent that application lifecycle
 	listeners. You should select at least one of the intefaces.
 	<ul>
 		<li><strong>javax.servlet.ServletContextListener:
 		</strong> This interface is provided by javax.servlet package and can be used
 		to listen to the ServletContext life-cycle events. This interface has
 		two methods: contextInitialized and contextDestroyed. The
 		<b><i>contextInitialized</i></b> method is called when the web application is ready
 		to service requests and the <b><i>contextDestroyed</i></b> method is invoked when
 		the servlet context is about to be shut down.</li>
 		<li><strong>javax.servlet.ServletContextAttributeListener:
 		</strong> This interface is provided by javax.servlet package. It can be used
 		to be notified when any attribute is added to the ServletContext or if
 		any of the ServletContext's attributes are changed or removed. This
 		inetface has three methods: <b><i>attributeAdded, attributeRemoved</i></b> and
 		<b><i>attributeReplaced</i></b>.</li>
 		<li><strong>javax.servlet.ServletRequestListener:
 		</strong> This interface is provided by javax.servlet package. It can be used
 		to be notified when a request is coming in or out of scope in a Web
 		component. This interface has two methods: requestInitialized and
 		requestDestroyed. The <b><i>requestInitialized</i></b> method is called when it is
 		about to enter the first servlet or filter in each Web application. The <b><i>requestDestroyed</i></b> method is called when it exits the last servlet
 		or the first filter in the chain.</li>
 		<li><strong>javax.servlet.ServletRequestAttributeListener:
 		</strong> This interface is provided by javax.servlet package and can be used
 		to be notified when any request attribute is changed. This interface
 		has three methods: attributeAdded, attributeRemoved and
 		attributeReplaced. The <b><i>attributteAdded</i></b> method is called when a new
 		attribute was added to servlet request. The <b><i>attributeRemoved</i></b> method is
 		called when an existing attribute has been removed from the servlet
 		request. The <b><i>attributeReplaced</i></b> method is called when an attribute
 		was replaced on the servlet request.</li>
 		<li><strong>javax.servlet.http.HttpSessionListener:
 		</strong> This interface is provided by javax.servlet.http package and can be
 		used to listen to a session&apos;s life cycle events. This interface has
 		two methods: sessionCreated and sessionDestroyed. The <b><i>sessionCreated</i></b>
 		method is called when an HttpSession object is created. The
 		<b><i>sessionDestroyed</i></b> method is called when an HttpSession object is
 		invalidated.</li>
 		<li><strong>javax.servlet.http.HttpSessionActivationListener:
 		</strong> This interface is provided by javax.servlet.http package. It can be
 		used to listen to a container events notifying that sessions will be
 		passivated or activated. This interface has two methods:
 		sessionDidActivate and sessionWillPasivate. The <b><i>sessionDidActivate</i></b> is
 		called when the session has just been activated and the
 		<b><i>sessionWillPasivate</i></b> is called when the session is about to be
 		passivated.</li>
 		<li><strong>javax.servlet.http.HttpSessionAttributeListener:
 		</strong> This interface is provided by javax.servlet.http package and can be
 		used to listen to events related to session attributes. This interface
 		has three methods: attributeAdded, attributeRemoved and
 		attributeReplaced. The <b><i>attributeAdded</i></b> method is called when an
 		attribute is added to an HttpSession object. The <b><i>attributeRemoved</i></b> and
 		<b><i>attributeReplaced</i></b> methods are called when an HttpSession attribute is
 		removed or replaced, respectively.</li>
 		<li><strong>javax.servlet.http.HttpSessionBindingListener:
 		</strong> This interface is provided by javax.servlet.http package and can be
 		used to be notified when an object is bound to or unbound from a
 		session. This interface has two methods: valueBound and valueUnbound.
 		The <b><i>valueBound</i></b> method is called when the object is being bound to a
 		session and identifies the session. The <b><i>valueUnbound</i></b> method is called
 		when the object is being unbound from a session and identifies the
 		session.</li>
 	</ul>
 	</dd>

 	<p>
 	<dt class="dlterm">Modifiers</dt>
 	</p>

 	<dd>The <cite>Sun Microsystems Java Servlet Specification</cite> states that a
 	Listener class must be <b>public</b> and not <b>abstract</b>. Therefore,
 	you cannot change these modifiers. The only one available for change is
 	the <b>final</b> modifier. </dd>

 	<p>
 	<dt class="dlterm">Interfaces</dt>
 	</p>

 	<dd>The interfaces that you selected in the previous page of the wizard
 	are provided as default values in the <b>Interfaces</b> field. To add
 	additional interfaces, click the <b>Add</b> button next to this field.</dd>

 	<p>
 	<dt class="dlterm">Interfaces dialog</dt>
 	</p>

 	<dd>This dialog appears if you select to add an interface to your
 	servlet. As you type the name of the interface that you are adding, a
 	list of available interfaces listed in the <b>Matching items</b> list box
 	updates dynamically to display only the interfaces that match the
 	pattern. Choose an interface to see the qualifier, and then click <b>OK</b>
 	when finished.</dd>

 </dl>
 </div>

 </div>
 </body>
 </html>
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	<title>Creating Listeners</title>
	</head>
	<body id="twlstwiz">
	<a name="twlstwiz"><!-- --></a>


	<h1 class="topictitle1">Creating Listeners</h1>

	<div>
	<p>The listener wizard helps you create application lifecycle
	listeners by walking you through the creation process and by providing
	you with output files that you can use or that you can modify for use
	with your Web application. The listeners can run on Java EE-compliant
	Web servers.</p>

	<div class="section">
	<p>To create a listener, complete the following steps:</p>
	</div>

	<ol>
	<li class="stepexpand"><span>In the Java EE perspective,
	expand your <a href="ccwebprj.html" title="">dynamic project</a> in the
	Project Explorer view.</span></li>

	<li class="stepexpand"><span>Right click on the <strong>Listener</strong>
	icon, and select <span class="menucascade"> <span
	class="uicontrol">New</span> > <span class="uicontrol">Listener</span></span>
	from the pop-up menu.</span> The <span class="uicontrol">Create Listener</span>
	wizard appears.</li>

	<li class="stepexpand"><span>Follow the project wizard
	prompts.</span></li>

	</ol>

	<div class="section">
	<p><strong>General Information</strong></p>
	<dl>

	<p>
	<dt class="dlterm">Application lifecycle listeners</dt>
	</p>

	<dd>The <cite>Sun Microsystems Java Servlet Specification</cite> defines the
	following interfaces that represent that application lifecycle
	listeners. You should select at least one of the intefaces.
	<ul>
	<li><strong>javax.servlet.ServletContextListener:
	</strong> This interface is provided by javax.servlet package and can be used
	to listen to the ServletContext life-cycle events. This interface has
	two methods: contextInitialized and contextDestroyed. The
	<b><i>contextInitialized</i></b> method is called when the web application is ready
	to service requests and the <b><i>contextDestroyed</i></b> method is invoked when
	the servlet context is about to be shut down.</li>
	<li><strong>javax.servlet.ServletContextAttributeListener:
	</strong> This interface is provided by javax.servlet package. It can be used
	to be notified when any attribute is added to the ServletContext or if
	any of the ServletContext's attributes are changed or removed. This
	inetface has three methods: <b><i>attributeAdded, attributeRemoved</i></b> and
	<b><i>attributeReplaced</i></b>.</li>
	<li><strong>javax.servlet.ServletRequestListener:
	</strong> This interface is provided by javax.servlet package. It can be used
	to be notified when a request is coming in or out of scope in a Web
	component. This interface has two methods: requestInitialized and
	requestDestroyed. The <b><i>requestInitialized</i></b> method is called when it is
	about to enter the first servlet or filter in each Web application. The <b><i>requestDestroyed</i></b> method is called when it exits the last servlet
	or the first filter in the chain.</li>
	<li><strong>javax.servlet.ServletRequestAttributeListener:
	</strong> This interface is provided by javax.servlet package and can be used
	to be notified when any request attribute is changed. This interface
	has three methods: attributeAdded, attributeRemoved and
	attributeReplaced. The <b><i>attributteAdded</i></b> method is called when a new
	attribute was added to servlet request. The <b><i>attributeRemoved</i></b> method is
	called when an existing attribute has been removed from the servlet
	request. The <b><i>attributeReplaced</i></b> method is called when an attribute
	was replaced on the servlet request.</li>
	<li><strong>javax.servlet.http.HttpSessionListener:
	</strong> This interface is provided by javax.servlet.http package and can be
	used to listen to a session's life cycle events. This interface has
	two methods: sessionCreated and sessionDestroyed. The <b><i>sessionCreated</i></b>
	method is called when an HttpSession object is created. The
	<b><i>sessionDestroyed</i></b> method is called when an HttpSession object is
	invalidated.</li>
	<li><strong>javax.servlet.http.HttpSessionActivationListener:
	</strong> This interface is provided by javax.servlet.http package. It can be
	used to listen to a container events notifying that sessions will be
	passivated or activated. This interface has two methods:
	sessionDidActivate and sessionWillPasivate. The <b><i>sessionDidActivate</i></b> is
	called when the session has just been activated and the
	<b><i>sessionWillPasivate</i></b> is called when the session is about to be
	passivated.</li>
	<li><strong>javax.servlet.http.HttpSessionAttributeListener:
	</strong> This interface is provided by javax.servlet.http package and can be
	used to listen to events related to session attributes. This interface
	has three methods: attributeAdded, attributeRemoved and
	attributeReplaced. The <b><i>attributeAdded</i></b> method is called when an
	attribute is added to an HttpSession object. The <b><i>attributeRemoved</i></b> and
	<b><i>attributeReplaced</i></b> methods are called when an HttpSession attribute is
	removed or replaced, respectively.</li>
	<li><strong>javax.servlet.http.HttpSessionBindingListener:
	</strong> This interface is provided by javax.servlet.http package and can be
	used to be notified when an object is bound to or unbound from a
	session. This interface has two methods: valueBound and valueUnbound.
	The <b><i>valueBound</i></b> method is called when the object is being bound to a
	session and identifies the session. The <b><i>valueUnbound</i></b> method is called
	when the object is being unbound from a session and identifies the
	session.</li>
	</ul>
	</dd>

	<p>
	<dt class="dlterm">Modifiers</dt>
	</p>

	<dd>The <cite>Sun Microsystems Java Servlet Specification</cite> states that a
	Listener class must be <b>public</b> and not <b>abstract</b>. Therefore,
	you cannot change these modifiers. The only one available for change is
	the <b>final</b> modifier. </dd>

	<p>
	<dt class="dlterm">Interfaces</dt>
	</p>

	<dd>The interfaces that you selected in the previous page of the wizard
	are provided as default values in the <b>Interfaces</b> field. To add
	additional interfaces, click the <b>Add</b> button next to this field.</dd>

	<p>
	<dt class="dlterm">Interfaces dialog</dt>
	</p>

	<dd>This dialog appears if you select to add an interface to your
	servlet. As you type the name of the interface that you are adding, a
	list of available interfaces listed in the <b>Matching items</b> list box
	updates dynamically to display only the interfaces that match the
	pattern. Choose an interface to see the qualifier, and then click <b>OK</b>
	when finished.</dd>

	</dl>
	</div>

	</div>
	</body>
	</html>