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/*******************************************************************************
* Copyright (c) 2003, 2006 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.ui.commands;
import java.util.Map;
import org.eclipse.ui.internal.util.Util;
/**
* An instance of this class describes changes to an instance of
* <code>IHandler</code>.
* <p>
* This class is not intended to be extended by clients.
* </p>
*
* @since 3.0
* @see IHandlerListener#handlerChanged(HandlerEvent)
* @deprecated Please use the "org.eclipse.core.commands" plug-in instead.
*/
public final class HandlerEvent {
/**
* Whether the attributes of the handler changed.
*/
private final boolean attributeValuesByNameChanged;
/**
* The handler that changed; this value is never <code>null</code>.
*/
private final IHandler handler;
/**
* This is the cached result of getPreviousAttributeValuesByName. It is
* computed the first time getPreviousAttributeValuesByName is called.
*/
private Map previousAttributeValuesByName;
/**
* The map of previous attributes, if they changed. If they did not change,
* then this value is <code>null</code>. The map's keys are the attribute
* names (strings), and its value are any object.
*
* This is the original map passed into the constructor. This object always
* returns a copy of this map, not the original. However the constructor of
* this object is called very frequently and the map is rarely requested,
* so we only copy the map the first time it is requested.
*
* @since 3.1
*/
private final Map originalPreviousAttributeValuesByName;
/**
* Creates a new instance of this class.
*
* @param handler
* the instance of the interface that changed.
* @param attributeValuesByNameChanged
* true, iff the attributeValuesByName property changed.
* @param previousAttributeValuesByName
* the map of previous attribute values by name. This map may be
* empty. If this map is not empty, it's collection of keys must
* only contain instances of <code>String</code>. This map
* must be <code>null</code> if attributeValuesByNameChanged is
* <code>false</code> and must not be null if
* attributeValuesByNameChanged is <code>true</code>.
*/
public HandlerEvent(IHandler handler, boolean attributeValuesByNameChanged,
Map previousAttributeValuesByName) {
if (handler == null) {
throw new NullPointerException();
}
if (!attributeValuesByNameChanged
&& previousAttributeValuesByName != null) {
throw new IllegalArgumentException();
}
if (attributeValuesByNameChanged) {
this.originalPreviousAttributeValuesByName = previousAttributeValuesByName;
} else {
this.originalPreviousAttributeValuesByName = null;
}
this.handler = handler;
this.attributeValuesByNameChanged = attributeValuesByNameChanged;
}
/**
* Returns the instance of the interface that changed.
*
* @return the instance of the interface that changed. Guaranteed not to be
* <code>null</code>.
*/
public IHandler getHandler() {
return handler;
}
/**
* Returns the map of previous attribute values by name.
*
* @return the map of previous attribute values by name. This map may be
* empty. If this map is not empty, it's collection of keys is
* guaranteed to only contain instances of <code>String</code>.
* This map is guaranteed to be <code>null</code> if
* haveAttributeValuesByNameChanged() is <code>false</code> and is
* guaranteed to not be null if haveAttributeValuesByNameChanged()
* is <code>true</code>.
*/
public Map getPreviousAttributeValuesByName() {
if (originalPreviousAttributeValuesByName == null) {
return null;
}
if (previousAttributeValuesByName == null) {
previousAttributeValuesByName = Util.safeCopy(
originalPreviousAttributeValuesByName, String.class, Object.class,
false, true);
}
return previousAttributeValuesByName;
}
/**
* Returns whether or not the attributeValuesByName property changed.
*
* @return true, iff the attributeValuesByName property changed.
*/
public boolean haveAttributeValuesByNameChanged() {
return attributeValuesByNameChanged;
}
}
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