/* |
|
* Copyright (c) 1999, 2000, Oracle and/or its affiliates. All rights reserved. |
|
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
|
* |
|
* This code is free software; you can redistribute it and/or modify it |
|
* under the terms of the GNU General Public License version 2 only, as |
|
* published by the Free Software Foundation. Oracle designates this |
|
* particular file as subject to the "Classpath" exception as provided |
|
* by Oracle in the LICENSE file that accompanied this code. |
|
* |
|
* This code is distributed in the hope that it will be useful, but WITHOUT |
|
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
|
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
|
* version 2 for more details (a copy is included in the LICENSE file that |
|
* accompanied this code). |
|
* |
|
* You should have received a copy of the GNU General Public License version |
|
* 2 along with this work; if not, write to the Free Software Foundation, |
|
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
|
* |
|
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
|
* or visit www.oracle.com if you need additional information or have any |
|
* questions. |
|
*/ |
|
package javax.naming.event; |
|
import javax.naming.Binding; |
|
/** |
|
* This class represents an event fired by a naming/directory service. |
|
*<p> |
|
* The <tt>NamingEvent</tt>'s state consists of |
|
* <ul> |
|
* <li>The event source: the <tt>EventContext</tt> which fired this event. |
|
* <li>The event type. |
|
* <li>The new binding: information about the object after the change. |
|
* <li>The old binding: information about the object before the change. |
|
* <li>Change information: information about the change |
|
* that triggered this event; usually service provider-specific or server-specific |
|
* information. |
|
* </ul> |
|
* <p> |
|
* Note that the event source is always the same <tt>EventContext</tt> |
|
* <em>instance</em> that the listener has registered with. |
|
* Furthermore, the names of the bindings in |
|
* the <tt>NamingEvent</tt> are always relative to that instance. |
|
* For example, suppose a listener makes the following registration: |
|
*<blockquote><pre> |
|
* NamespaceChangeListener listener = ...; |
|
* src.addNamingListener("x", SUBTREE_SCOPE, listener); |
|
*</pre></blockquote> |
|
* When an object named "x/y" is subsequently deleted, the corresponding |
|
* <tt>NamingEvent</tt> (<tt>evt</tt>) must contain: |
|
*<blockquote><pre> |
|
* evt.getEventContext() == src |
|
* evt.getOldBinding().getName().equals("x/y") |
|
*</pre></blockquote> |
|
* |
|
* Care must be taken when multiple threads are accessing the same |
|
* <tt>EventContext</tt> concurrently. |
|
* See the |
|
* <a href=package-summary.html#THREADING>package description</a> |
|
* for more information on threading issues. |
|
* |
|
* @author Rosanna Lee |
|
* @author Scott Seligman |
|
* |
|
* @see NamingListener |
|
* @see EventContext |
|
* @since 1.3 |
|
*/ |
|
public class NamingEvent extends java.util.EventObject { |
|
/** |
|
* Naming event type for indicating that a new object has been added. |
|
* The value of this constant is <tt>0</tt>. |
|
*/ |
|
public static final int OBJECT_ADDED = 0; |
|
/** |
|
* Naming event type for indicating that an object has been removed. |
|
* The value of this constant is <tt>1</tt>. |
|
*/ |
|
public static final int OBJECT_REMOVED = 1; |
|
/** |
|
* Naming event type for indicating that an object has been renamed. |
|
* Note that some services might fire multiple events for a single |
|
* logical rename operation. For example, the rename operation might |
|
* be implemented by adding a binding with the new name and removing |
|
* the old binding. |
|
*<p> |
|
* The old/new binding in <tt>NamingEvent</tt> may be null if the old |
|
* name or new name is outside of the scope for which the listener |
|
* has registered. |
|
*<p> |
|
* When an interior node in the namespace tree has been renamed, the |
|
* topmost node which is part of the listener's scope should used to generate |
|
* a rename event. The extent to which this can be supported is |
|
* provider-specific. For example, a service might generate rename |
|
* notifications for all descendants of the changed interior node and the |
|
* corresponding provider might not be able to prevent those |
|
* notifications from being propagated to the listeners. |
|
*<p> |
|
* The value of this constant is <tt>2</tt>. |
|
*/ |
|
public static final int OBJECT_RENAMED = 2; |
|
/** |
|
* Naming event type for indicating that an object has been changed. |
|
* The changes might include the object's attributes, or the object itself. |
|
* Note that some services might fire multiple events for a single |
|
* modification. For example, the modification might |
|
* be implemented by first removing the old binding and adding |
|
* a new binding containing the same name but a different object. |
|
*<p> |
|
* The value of this constant is <tt>3</tt>. |
|
*/ |
|
public static final int OBJECT_CHANGED = 3; |
|
/** |
|
* Contains information about the change that generated this event. |
|
* @serial |
|
*/ |
|
protected Object changeInfo; |
|
/** |
|
* Contains the type of this event. |
|
* @see #OBJECT_ADDED |
|
* @see #OBJECT_REMOVED |
|
* @see #OBJECT_RENAMED |
|
* @see #OBJECT_CHANGED |
|
* @serial |
|
*/ |
|
protected int type; |
|
/** |
|
* Contains information about the object before the change. |
|
* @serial |
|
*/ |
|
protected Binding oldBinding; |
|
/** |
|
* Contains information about the object after the change. |
|
* @serial |
|
*/ |
|
protected Binding newBinding; |
|
/** |
|
* Constructs an instance of <tt>NamingEvent</tt>. |
|
*<p> |
|
* The names in <tt>newBd</tt> and <tt>oldBd</tt> are to be resolved relative |
|
* to the event source <tt>source</tt>. |
|
* |
|
* For an <tt>OBJECT_ADDED</tt> event type, <tt>newBd</tt> must not be null. |
|
* For an <tt>OBJECT_REMOVED</tt> event type, <tt>oldBd</tt> must not be null. |
|
* For an <tt>OBJECT_CHANGED</tt> event type, <tt>newBd</tt> and |
|
* <tt>oldBd</tt> must not be null. For an <tt>OBJECT_RENAMED</tt> event type, |
|
* one of <tt>newBd</tt> or <tt>oldBd</tt> may be null if the new or old |
|
* binding is outside of the scope for which the listener has registered. |
|
* |
|
* @param source The non-null context that fired this event. |
|
* @param type The type of the event. |
|
* @param newBd A possibly null binding before the change. See method description. |
|
* @param oldBd A possibly null binding after the change. See method description. |
|
* @param changeInfo A possibly null object containing information about the change. |
|
* @see #OBJECT_ADDED |
|
* @see #OBJECT_REMOVED |
|
* @see #OBJECT_RENAMED |
|
* @see #OBJECT_CHANGED |
|
*/ |
|
public NamingEvent(EventContext source, int type, |
|
Binding newBd, Binding oldBd, Object changeInfo) { |
|
super(source); |
|
this.type = type; |
|
oldBinding = oldBd; |
|
newBinding = newBd; |
|
this.changeInfo = changeInfo; |
|
} |
|
/** |
|
* Returns the type of this event. |
|
* @return The type of this event. |
|
* @see #OBJECT_ADDED |
|
* @see #OBJECT_REMOVED |
|
* @see #OBJECT_RENAMED |
|
* @see #OBJECT_CHANGED |
|
*/ |
|
public int getType() { |
|
return type; |
|
} |
|
/** |
|
* Retrieves the event source that fired this event. |
|
* This returns the same object as <tt>EventObject.getSource()</tt>. |
|
*<p> |
|
* If the result of this method is used to access the |
|
* event source, for example, to look up the object or get its attributes, |
|
* then it needs to be locked because implementations of <tt>Context</tt> |
|
* are not guaranteed to be thread-safe |
|
* (and <tt>EventContext</tt> is a subinterface of <tt>Context</tt>). |
|
* See the |
|
* <a href=package-summary.html#THREADING>package description</a> |
|
* for more information on threading issues. |
|
* |
|
* @return The non-null context that fired this event. |
|
*/ |
|
public EventContext getEventContext() { |
|
return (EventContext)getSource(); |
|
} |
|
/** |
|
* Retrieves the binding of the object before the change. |
|
*<p> |
|
* The binding must be nonnull if the object existed before the change |
|
* relative to the source context (<tt>getEventContext()</tt>). |
|
* That is, it must be nonnull for <tt>OBJECT_REMOVED</tt> and |
|
* <tt>OBJECT_CHANGED</tt>. |
|
* For <tt>OBJECT_RENAMED</tt>, it is null if the object before the rename |
|
* is outside of the scope for which the listener has registered interest; |
|
* it is nonnull if the object is inside the scope before the rename. |
|
*<p> |
|
* The name in the binding is to be resolved relative |
|
* to the event source <tt>getEventContext()</tt>. |
|
* The object returned by <tt>Binding.getObject()</tt> may be null if |
|
* such information is unavailable. |
|
* |
|
* @return The possibly null binding of the object before the change. |
|
*/ |
|
public Binding getOldBinding() { |
|
return oldBinding; |
|
} |
|
/** |
|
* Retrieves the binding of the object after the change. |
|
*<p> |
|
* The binding must be nonnull if the object existed after the change |
|
* relative to the source context (<tt>getEventContext()</tt>). |
|
* That is, it must be nonnull for <tt>OBJECT_ADDED</tt> and |
|
* <tt>OBJECT_CHANGED</tt>. For <tt>OBJECT_RENAMED</tt>, |
|
* it is null if the object after the rename is outside the scope for |
|
* which the listener registered interest; it is nonnull if the object |
|
* is inside the scope after the rename. |
|
*<p> |
|
* The name in the binding is to be resolved relative |
|
* to the event source <tt>getEventContext()</tt>. |
|
* The object returned by <tt>Binding.getObject()</tt> may be null if |
|
* such information is unavailable. |
|
* |
|
* @return The possibly null binding of the object after the change. |
|
*/ |
|
public Binding getNewBinding() { |
|
return newBinding; |
|
} |
|
/** |
|
* Retrieves the change information for this event. |
|
* The value of the change information is service-specific. For example, |
|
* it could be an ID that identifies the change in a change log on the server. |
|
* |
|
* @return The possibly null change information of this event. |
|
*/ |
|
public Object getChangeInfo() { |
|
return changeInfo; |
|
} |
|
/** |
|
* Invokes the appropriate listener method on this event. |
|
* The default implementation of |
|
* this method handles the following event types: |
|
* <tt>OBJECT_ADDED</TT>, <TT>OBJECT_REMOVED</TT>, |
|
* <TT>OBJECT_RENAMED</TT>, <TT>OBJECT_CHANGED</TT>. |
|
*<p> |
|
* The listener method is executed in the same thread |
|
* as this method. See the |
|
* <a href=package-summary.html#THREADING>package description</a> |
|
* for more information on threading issues. |
|
* @param listener The nonnull listener. |
|
*/ |
|
public void dispatch(NamingListener listener) { |
|
switch (type) { |
|
case OBJECT_ADDED: |
|
((NamespaceChangeListener)listener).objectAdded(this); |
|
break; |
|
case OBJECT_REMOVED: |
|
((NamespaceChangeListener)listener).objectRemoved(this); |
|
break; |
|
case OBJECT_RENAMED: |
|
((NamespaceChangeListener)listener).objectRenamed(this); |
|
break; |
|
case OBJECT_CHANGED: |
|
((ObjectChangeListener)listener).objectChanged(this); |
|
break; |
|
} |
|
} |
|
private static final long serialVersionUID = -7126752885365133499L; |
|
} |