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 <html><head>
       <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
    <title>3.&nbsp; Lifecycle Callbacks</title><base href="display"><link rel="stylesheet" type="text/css" href="css/docbook.css"><meta name="generator" content="DocBook XSL-NS Stylesheets V1.76.1"><link rel="home" href="manual.html" title="Apache OpenJPA 2.3 User's Guide"><link rel="up" href="jpa_overview_pc.html" title="Chapter&nbsp;4.&nbsp; Entity"><link rel="prev" href="jpa_overview_pc_identity.html" title="2.&nbsp; Entity Identity"><link rel="next" href="jpa_overview_pc_conclusion.html" title="4.&nbsp; Conclusions"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">3.&nbsp;
             Lifecycle Callbacks
         </th></tr><tr><td width="20%" align="left"><a accesskey="p" href="jpa_overview_pc_identity.html">Prev</a>&nbsp;</td><th width="60%" align="center">Chapter&nbsp;4.&nbsp;
         Entity
     </th><td width="20%" align="right">&nbsp;<a accesskey="n" href="jpa_overview_pc_conclusion.html">Next</a></td></tr></table><hr></div><div class="section" title="3.&nbsp; Lifecycle Callbacks"><div class="titlepage"><div><div><h2 class="title" style="clear: both" id="jpa_overview_pc_callbacks">3.&nbsp;
             Lifecycle Callbacks
         </h2></div></div></div><div class="toc"><dl><dt><span class="section"><a href="jpa_overview_pc_callbacks.html#jpa_overview_pc_callbacks_methods">3.1.
                 Callback Methods
             </a></span></dt><dt><span class="section"><a href="jpa_overview_pc_callbacks.html#jpa_overview_callbacks_using">3.2.
                 Using Callback Methods
             </a></span></dt><dt><span class="section"><a href="jpa_overview_pc_callbacks.html#jpa_overview_entity_listeners_using">3.3.
                 Using Entity Listeners
             </a></span></dt><dt><span class="section"><a href="jpa_overview_pc_callbacks.html#jpa_overview_entity_listeners_exclude">3.4.
                 Entity Listeners Hierarchy
             </a></span></dt></dl></div>

         <a class="indexterm" name="d5e874"></a>
         <a class="indexterm" name="d5e876"></a>
         <p>
 It is often necessary to perform various actions at different stages of a
 persistent object's lifecycle. JPA includes a variety of callbacks methods for
 monitoring changes in the lifecycle of your persistent objects. These callbacks
 can be defined on the persistent classes themselves and on non-persistent
 listener classes.
         </p>
         <div class="section" title="3.1.&nbsp; Callback Methods"><div class="titlepage"><div><div><h3 class="title" id="jpa_overview_pc_callbacks_methods">3.1.&nbsp;
                 Callback Methods
             </h3></div></div></div>

             <a class="indexterm" name="d5e883"></a>
             <a class="indexterm" name="d5e886"></a>
             <p>
 Every persistence event has a corresponding callback method marker. These
 markers are shared between persistent classes and their listeners. You can use
 these markers to designate a method for callback either by annotating that
 method or by listing the method in the XML mapping file for a given class. The
 lifecycle events and their corresponding method markers are:
             </p>
             <div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
                     <p>
                     <a class="indexterm" name="d5e893"></a>
 <a class="ulink" href="http://download.oracle.com/javaee/6/api/javax/persistence/PrePersist.html" target="_top">
 <code class="classname">PrePersist</code></a>: Methods marked with this annotation
 will be invoked before an object is persisted. This could be used for assigning
 primary key values to persistent objects. This is equivalent to the XML element
 tag <code class="literal">pre-persist</code>.
                     </p>
                 </li><li class="listitem">
                     <p>
                     <a class="indexterm" name="d5e901"></a>
 <a class="ulink" href="http://download.oracle.com/javaee/6/api/javax/persistence/PostPersist.html" target="_top">
 <code class="classname">PostPersist</code></a>: Methods marked with this annotation
 will be invoked after an object has transitioned to the persistent state. You
 might want to use such methods to update a screen after a new row is added. This
 is equivalent to the XML element tag <code class="literal">post-persist</code>.
                     </p>
                 </li><li class="listitem">
                     <p>
                     <a class="indexterm" name="d5e909"></a>
 <a class="ulink" href="http://download.oracle.com/javaee/6/api/javax/persistence/PostLoad.html" target="_top">
 <code class="classname">PostLoad</code></a>: Methods marked with this annotation
 will be invoked after all eagerly fetched fields of your class have been loaded
 from the datastore. No other persistent fields can be accessed in this method.
 This is equivalent to the XML element tag <code class="literal">post-load</code>.
                     </p>
                     <p>
 <code class="classname">PostLoad</code> is often used to initialize non-persistent
 fields whose values depend on the values of persistent fields, such as a complex
 data structure.
                     </p>
                 </li><li class="listitem">
                     <p>
                     <a class="indexterm" name="d5e919"></a>
 <a class="ulink" href="http://download.oracle.com/javaee/6/api/javax/persistence/PreUpdate.html" target="_top">
 <code class="classname">PreUpdate</code></a>: Methods marked with this annotation
 will be invoked just the persistent values in your objects are flushed to the
 datastore. This is equivalent to the XML element tag <code class="literal">
 pre-update</code>.
                     </p>
                     <p>
 <code class="classname">PreUpdate</code> is the complement to <code class="classname">PostLoad
 </code>. While methods marked with <code class="classname">PostLoad</code> are most
 often used to initialize non-persistent values from persistent data, methods
 annotated with <code class="classname">PreUpdate</code> is normally used to set
 persistent fields with information cached in non-persistent data.
                     </p>
                 </li><li class="listitem">
                     <p>
                     <a class="indexterm" name="d5e932"></a>
 <a class="ulink" href="http://download.oracle.com/javaee/6/api/javax/persistence/PostUpdate.html" target="_top">
 <code class="classname">PostUpdate</code></a>: Methods marked with this annotation
 will be invoked after changes to a given instance have been stored to the
 datastore. This is useful for clearing stale data cached at the application
 layer. This is equivalent to the XML element tag <code class="literal">post-update</code>.
                     </p>
                 </li><li class="listitem">
                     <p>
                     <a class="indexterm" name="d5e940"></a>
 <a class="ulink" href="http://download.oracle.com/javaee/6/api/javax/persistence/PreRemove.html" target="_top">
 <code class="classname">PreRemove</code></a>: Methods marked with this annotation
 will be invoked before an object transactions to the deleted state. Access to
 persistent fields is valid within this method. You might use this method to
 cascade the deletion to related objects based on complex criteria, or to perform
 other cleanup. This is equivalent to the XML element tag <code class="literal">
 pre-remove</code>.
                     </p>
                 </li><li class="listitem">
                     <p>
                     <a class="indexterm" name="d5e948"></a>
 <a class="ulink" href="http://download.oracle.com/javaee/6/api/javax/persistence/PostRemove.html" target="_top">
 <code class="classname">PostRemove</code></a>: Methods marked with this annotation
 will be invoked after an object has been marked as to be deleted. This is
 equivalent to the XML element tag <code class="literal">post-remove</code>.
                     </p>
                 </li></ul></div>
         </div>
         <div class="section" title="3.2.&nbsp; Using Callback Methods"><div class="titlepage"><div><div><h3 class="title" id="jpa_overview_callbacks_using">3.2.&nbsp;
                 Using Callback Methods
             </h3></div></div></div>

             <p>
 When declaring callback methods on a persistent class, any method may be used
 which takes no arguments and is not shared with any property access fields.
 Multiple events can be assigned to a single method as well.
             </p>
             <p>
 Below is an example of how to declare callback methods on persistent classes:
             </p>
 <pre class="programlisting">
 /**
  * Example persistent class declaring our entity listener.
  */
 @Entity
 public class Magazine {

     @Transient
     private byte[][] data;

     @ManyToMany
     private List&lt;Photo&gt; photos;

     @PostLoad
     public void convertPhotos() {
         data = new byte[photos.size()][];
         for (int i = 0; i &lt; photos.size(); i++)
             data[i] = photos.get(i).toByteArray();
     }

     @PreDelete
     public void logMagazineDeletion() {
         getLog().debug("deleting magazine containing" + photos.size()
             + " photos.");
     }
 }

 </pre>
             <p>
 In an XML mapping file, we can define the same methods without annotations:
             </p>
 <pre class="programlisting">
 &lt;entity class="Magazine"&gt;
     &lt;pre-remove&gt;logMagazineDeletion&lt;/pre-remove&gt;
     &lt;post-load&gt;convertPhotos&lt;/post-load&gt;
 &lt;/entity&gt;
 </pre>
             <div class="note" title="Note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3>
                 <p>
 We fully explore persistence metadata annotations and XML in
 <a class="xref" href="jpa_overview_meta.html" title="Chapter&nbsp;5.&nbsp; Metadata">Chapter&nbsp;5, <i>
         Metadata
     </i></a>.
                 </p>
             </div>
         </div>
         <div class="section" title="3.3.&nbsp; Using Entity Listeners"><div class="titlepage"><div><div><h3 class="title" id="jpa_overview_entity_listeners_using">3.3.&nbsp;
                 Using Entity Listeners
             </h3></div></div></div>

             <p>
 Mixing lifecycle event code into your persistent classes is not always ideal. It
 is often more elegant to handle cross-cutting lifecycle events in a
 non-persistent listener class. JPA allows for this, requiring only that listener
 classes have a public no-arg constructor. Like persistent classes, your listener
 classes can consume any number of callbacks. The callback methods must take in a
 single <code class="classname">java.lang.Object</code> argument which represents the
 persistent object that triggered the event.
             </p>
             <p>
 Entities can enumerate listeners using the <code class="classname">EntityListeners
 </code> annotation. This annotation takes an array of listener classes as
 its value.
             </p>
             <p>
 Below is an example of how to declare an entity and its corresponding listener
 classes.
             </p>
 <pre class="programlisting">
 /**
  * Example persistent class declaring our entity listener.
  */
 @Entity
 @EntityListeners({ MagazineLogger.class, ... })
 public class Magazine {

     // ... //
 }


 /**
  * Example entity listener.
  */
 public class MagazineLogger {

     @PostPersist
     public void logAddition(Object pc) {
         getLog().debug("Added new magazine:" + ((Magazine) pc).getTitle());
     }


     @PreRemove
     public void logDeletion(Object pc) {
         getLog().debug("Removing from circulation:" +
             ((Magazine) pc).getTitle());
     }
 }
 </pre>
             <p>
 In XML, we define both the listeners and their callback methods as so:
             </p>
 <pre class="programlisting">
 &lt;entity class="Magazine"&gt;
     &lt;entity-listeners&gt;
         &lt;entity-listener class="MagazineLogger"&gt;
             &lt;post-persist&gt;logAddition&lt;/post-persist&gt;
             &lt;pre-remove&gt;logDeletion&lt;/pre-remove&gt;
         &lt;/entity-listener&gt;
     &lt;/entity-listeners&gt;
 &lt;/entity&gt;
 </pre>
         </div>
         <div class="section" title="3.4.&nbsp; Entity Listeners Hierarchy"><div class="titlepage"><div><div><h3 class="title" id="jpa_overview_entity_listeners_exclude">3.4.&nbsp;
                 Entity Listeners Hierarchy
             </h3></div></div></div>

             <a class="indexterm" name="d5e976"></a>
             <p>
 Entity listener methods are invoked in a specific order when a given event is
 fired. So-called <span class="emphasis"><em>default</em></span> listeners are invoked first: these
 are listeners which have been defined in a package annotation or in the root
 element of XML mapping files. Next, entity listeners are invoked in the order of
 the inheritance hierarchy, with superclass listeners being invoked before
 subclass listeners. Finally, if an entity has multiple listeners for the same
 event, the listeners are invoked in declaration order.
             </p>
             <p>
 You can exclude default listeners and listeners defined in superclasses from the
 invocation chain through the use of two class-level annotations:
             </p>
             <div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
                     <p>
 <code class="classname">ExcludeDefaultListeners</code>: This annotation indicates that
 no default listeners will be invoked for this class, or any of its subclasses.
 The XML equivalent is the empty <code class="literal">exclude-default-listeners</code>
 element.
                     </p>
                 </li><li class="listitem">
                     <p>
 <code class="classname">ExcludeSuperclassListeners</code>: This annotation will cause
 OpenJPA to skip invoking any listeners declared in superclasses. The XML
 equivalent is the empty <code class="literal">exclude-superclass-listeners</code> element.
                     </p>
                 </li></ul></div>
         </div>
     </div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="jpa_overview_pc_identity.html">Prev</a>&nbsp;</td><td width="20%" align="center"><a accesskey="u" href="jpa_overview_pc.html">Up</a></td><td width="40%" align="right">&nbsp;<a accesskey="n" href="jpa_overview_pc_conclusion.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">2.&nbsp;
             Entity Identity
         &nbsp;</td><td width="20%" align="center"><a accesskey="h" href="manual.html">Home</a></td><td width="40%" align="right" valign="top">&nbsp;4.&nbsp;
             Conclusions
         </td></tr></table></div></body></html>
	<html><head>
	<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
	<title>3.  Lifecycle Callbacks</title><base href="display"><link rel="stylesheet" type="text/css" href="css/docbook.css"><meta name="generator" content="DocBook XSL-NS Stylesheets V1.76.1"><link rel="home" href="manual.html" title="Apache OpenJPA 2.3 User's Guide"><link rel="up" href="jpa_overview_pc.html" title="Chapter 4.  Entity"><link rel="prev" href="jpa_overview_pc_identity.html" title="2.  Entity Identity"><link rel="next" href="jpa_overview_pc_conclusion.html" title="4.  Conclusions"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">3.
	Lifecycle Callbacks
	</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="jpa_overview_pc_identity.html">Prev</a> </td><th width="60%" align="center">Chapter 4.
	Entity
	</th><td width="20%" align="right"> <a accesskey="n" href="jpa_overview_pc_conclusion.html">Next</a></td></tr></table><hr></div><div class="section" title="3.  Lifecycle Callbacks"><div class="titlepage"><div><div><h2 class="title" style="clear: both" id="jpa_overview_pc_callbacks">3.
	Lifecycle Callbacks
	</h2></div></div></div><div class="toc"><dl><dt><span class="section"><a href="jpa_overview_pc_callbacks.html#jpa_overview_pc_callbacks_methods">3.1.
	Callback Methods
	</a></span></dt><dt><span class="section"><a href="jpa_overview_pc_callbacks.html#jpa_overview_callbacks_using">3.2.
	Using Callback Methods
	</a></span></dt><dt><span class="section"><a href="jpa_overview_pc_callbacks.html#jpa_overview_entity_listeners_using">3.3.
	Using Entity Listeners
	</a></span></dt><dt><span class="section"><a href="jpa_overview_pc_callbacks.html#jpa_overview_entity_listeners_exclude">3.4.
	Entity Listeners Hierarchy
	</a></span></dt></dl></div>

	<a class="indexterm" name="d5e874"></a>
	<a class="indexterm" name="d5e876"></a>
	<p>
	It is often necessary to perform various actions at different stages of a
	persistent object's lifecycle. JPA includes a variety of callbacks methods for
	monitoring changes in the lifecycle of your persistent objects. These callbacks
	can be defined on the persistent classes themselves and on non-persistent
	listener classes.
	</p>
	<div class="section" title="3.1.  Callback Methods"><div class="titlepage"><div><div><h3 class="title" id="jpa_overview_pc_callbacks_methods">3.1.
	Callback Methods
	</h3></div></div></div>

	<a class="indexterm" name="d5e883"></a>
	<a class="indexterm" name="d5e886"></a>
	<p>
	Every persistence event has a corresponding callback method marker. These
	markers are shared between persistent classes and their listeners. You can use
	these markers to designate a method for callback either by annotating that
	method or by listing the method in the XML mapping file for a given class. The
	lifecycle events and their corresponding method markers are:
	</p>
	<div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
	<p>
	<a class="indexterm" name="d5e893"></a>
	<a class="ulink" href="http://download.oracle.com/javaee/6/api/javax/persistence/PrePersist.html" target="_top">
	<code class="classname">PrePersist</code></a>: Methods marked with this annotation
	will be invoked before an object is persisted. This could be used for assigning
	primary key values to persistent objects. This is equivalent to the XML element
	tag <code class="literal">pre-persist</code>.
	</p>
	</li><li class="listitem">
	<p>
	<a class="indexterm" name="d5e901"></a>
	<a class="ulink" href="http://download.oracle.com/javaee/6/api/javax/persistence/PostPersist.html" target="_top">
	<code class="classname">PostPersist</code></a>: Methods marked with this annotation
	will be invoked after an object has transitioned to the persistent state. You
	might want to use such methods to update a screen after a new row is added. This
	is equivalent to the XML element tag <code class="literal">post-persist</code>.
	</p>
	</li><li class="listitem">
	<p>
	<a class="indexterm" name="d5e909"></a>
	<a class="ulink" href="http://download.oracle.com/javaee/6/api/javax/persistence/PostLoad.html" target="_top">
	<code class="classname">PostLoad</code></a>: Methods marked with this annotation
	will be invoked after all eagerly fetched fields of your class have been loaded
	from the datastore. No other persistent fields can be accessed in this method.
	This is equivalent to the XML element tag <code class="literal">post-load</code>.
	</p>
	<p>
	<code class="classname">PostLoad</code> is often used to initialize non-persistent
	fields whose values depend on the values of persistent fields, such as a complex
	data structure.
	</p>
	</li><li class="listitem">
	<p>
	<a class="indexterm" name="d5e919"></a>
	<a class="ulink" href="http://download.oracle.com/javaee/6/api/javax/persistence/PreUpdate.html" target="_top">
	<code class="classname">PreUpdate</code></a>: Methods marked with this annotation
	will be invoked just the persistent values in your objects are flushed to the
	datastore. This is equivalent to the XML element tag <code class="literal">
	pre-update</code>.
	</p>
	<p>
	<code class="classname">PreUpdate</code> is the complement to <code class="classname">PostLoad
	</code>. While methods marked with <code class="classname">PostLoad</code> are most
	often used to initialize non-persistent values from persistent data, methods
	annotated with <code class="classname">PreUpdate</code> is normally used to set
	persistent fields with information cached in non-persistent data.
	</p>
	</li><li class="listitem">
	<p>
	<a class="indexterm" name="d5e932"></a>
	<a class="ulink" href="http://download.oracle.com/javaee/6/api/javax/persistence/PostUpdate.html" target="_top">
	<code class="classname">PostUpdate</code></a>: Methods marked with this annotation
	will be invoked after changes to a given instance have been stored to the
	datastore. This is useful for clearing stale data cached at the application
	layer. This is equivalent to the XML element tag <code class="literal">post-update</code>.
	</p>
	</li><li class="listitem">
	<p>
	<a class="indexterm" name="d5e940"></a>
	<a class="ulink" href="http://download.oracle.com/javaee/6/api/javax/persistence/PreRemove.html" target="_top">
	<code class="classname">PreRemove</code></a>: Methods marked with this annotation
	will be invoked before an object transactions to the deleted state. Access to
	persistent fields is valid within this method. You might use this method to
	cascade the deletion to related objects based on complex criteria, or to perform
	other cleanup. This is equivalent to the XML element tag <code class="literal">
	pre-remove</code>.
	</p>
	</li><li class="listitem">
	<p>
	<a class="indexterm" name="d5e948"></a>
	<a class="ulink" href="http://download.oracle.com/javaee/6/api/javax/persistence/PostRemove.html" target="_top">
	<code class="classname">PostRemove</code></a>: Methods marked with this annotation
	will be invoked after an object has been marked as to be deleted. This is
	equivalent to the XML element tag <code class="literal">post-remove</code>.
	</p>
	</li></ul></div>
	</div>
	<div class="section" title="3.2.  Using Callback Methods"><div class="titlepage"><div><div><h3 class="title" id="jpa_overview_callbacks_using">3.2.
	Using Callback Methods
	</h3></div></div></div>

	<p>
	When declaring callback methods on a persistent class, any method may be used
	which takes no arguments and is not shared with any property access fields.
	Multiple events can be assigned to a single method as well.
	</p>
	<p>
	Below is an example of how to declare callback methods on persistent classes:
	</p>
	<pre class="programlisting">
	/**
	* Example persistent class declaring our entity listener.
	*/
	@Entity
	public class Magazine {

	@Transient
	private byte[][] data;

	@ManyToMany
	private List<Photo> photos;

	@PostLoad
	public void convertPhotos() {
	data = new byte[photos.size()][];
	for (int i = 0; i < photos.size(); i++)
	data[i] = photos.get(i).toByteArray();
	}

	@PreDelete
	public void logMagazineDeletion() {
	getLog().debug("deleting magazine containing" + photos.size()
	+ " photos.");
	}
	}

	</pre>
	<p>
	In an XML mapping file, we can define the same methods without annotations:
	</p>
	<pre class="programlisting">
	<entity class="Magazine">
	<pre-remove>logMagazineDeletion</pre-remove>
	<post-load>convertPhotos</post-load>
	</entity>
	</pre>
	<div class="note" title="Note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3>
	<p>
	We fully explore persistence metadata annotations and XML in
	<a class="xref" href="jpa_overview_meta.html" title="Chapter 5.  Metadata">Chapter 5, <i>
	Metadata
	</i></a>.
	</p>
	</div>
	</div>
	<div class="section" title="3.3.  Using Entity Listeners"><div class="titlepage"><div><div><h3 class="title" id="jpa_overview_entity_listeners_using">3.3.
	Using Entity Listeners
	</h3></div></div></div>

	<p>
	Mixing lifecycle event code into your persistent classes is not always ideal. It
	is often more elegant to handle cross-cutting lifecycle events in a
	non-persistent listener class. JPA allows for this, requiring only that listener
	classes have a public no-arg constructor. Like persistent classes, your listener
	classes can consume any number of callbacks. The callback methods must take in a
	single <code class="classname">java.lang.Object</code> argument which represents the
	persistent object that triggered the event.
	</p>
	<p>
	Entities can enumerate listeners using the <code class="classname">EntityListeners
	</code> annotation. This annotation takes an array of listener classes as
	its value.
	</p>
	<p>
	Below is an example of how to declare an entity and its corresponding listener
	classes.
	</p>
	<pre class="programlisting">
	/**
	* Example persistent class declaring our entity listener.
	*/
	@Entity
	@EntityListeners({ MagazineLogger.class, ... })
	public class Magazine {

	// ... //
	}


	/**
	* Example entity listener.
	*/
	public class MagazineLogger {

	@PostPersist
	public void logAddition(Object pc) {
	getLog().debug("Added new magazine:" + ((Magazine) pc).getTitle());
	}


	@PreRemove
	public void logDeletion(Object pc) {
	getLog().debug("Removing from circulation:" +
	((Magazine) pc).getTitle());
	}
	}
	</pre>
	<p>
	In XML, we define both the listeners and their callback methods as so:
	</p>
	<pre class="programlisting">
	<entity class="Magazine">
	<entity-listeners>
	<entity-listener class="MagazineLogger">
	<post-persist>logAddition</post-persist>
	<pre-remove>logDeletion</pre-remove>
	</entity-listener>
	</entity-listeners>
	</entity>
	</pre>
	</div>
	<div class="section" title="3.4.  Entity Listeners Hierarchy"><div class="titlepage"><div><div><h3 class="title" id="jpa_overview_entity_listeners_exclude">3.4.
	Entity Listeners Hierarchy
	</h3></div></div></div>

	<a class="indexterm" name="d5e976"></a>
	<p>
	Entity listener methods are invoked in a specific order when a given event is
	fired. So-called <span class="emphasis"><em>default</em></span> listeners are invoked first: these
	are listeners which have been defined in a package annotation or in the root
	element of XML mapping files. Next, entity listeners are invoked in the order of
	the inheritance hierarchy, with superclass listeners being invoked before
	subclass listeners. Finally, if an entity has multiple listeners for the same
	event, the listeners are invoked in declaration order.
	</p>
	<p>
	You can exclude default listeners and listeners defined in superclasses from the
	invocation chain through the use of two class-level annotations:
	</p>
	<div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
	<p>
	<code class="classname">ExcludeDefaultListeners</code>: This annotation indicates that
	no default listeners will be invoked for this class, or any of its subclasses.
	The XML equivalent is the empty <code class="literal">exclude-default-listeners</code>
	element.
	</p>
	</li><li class="listitem">
	<p>
	<code class="classname">ExcludeSuperclassListeners</code>: This annotation will cause
	OpenJPA to skip invoking any listeners declared in superclasses. The XML
	equivalent is the empty <code class="literal">exclude-superclass-listeners</code> element.
	</p>
	</li></ul></div>
	</div>
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