/*******************************************************************************
* Copyright (c) 2003, 2005 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.core.commands.contexts;
import java.util.Set;
import org.eclipse.core.commands.common.AbstractBitSetEvent;
/**
* <p>
* An event indicating that the set of defined context identifiers has changed.
* </p>
*
* @since 3.1
* @see IContextManagerListener#contextManagerChanged(ContextManagerEvent)
*/
public final class ContextManagerEvent extends AbstractBitSetEvent {
/**
* The bit used to represent whether the set of defined contexts has
* changed.
*/
private static final int CHANGED_CONTEXT_DEFINED = 1 << 1;
/**
* The bit used to represent whether the set of active contexts has changed.
*/
private static final int CHANGED_CONTEXTS_ACTIVE = 1;
/**
* The context identifier that was added or removed from the list of defined
* context identifiers.
*/
private final String contextId;
/**
* The context manager that has changed.
*/
private final ContextManager contextManager;
/**
* The set of context identifiers (strings) that were active before the
* change occurred. If the active contexts did not changed, then this value
* is <code>null</code>.
*/
private final Set previouslyActiveContextIds;
/**
* Creates a new instance of this class.
*
* @param contextManager
* the instance of the interface that changed; must not be
* <code>null</code>.
* @param contextId
* The context identifier that was added or removed; may be
* <code>null</code> if the active contexts are changing.
* @param contextIdAdded
* Whether the context identifier became defined (otherwise, it
* became undefined).
* @param activeContextsChanged
* Whether the list of active contexts has changed.
* @param previouslyActiveContextIds
* the set of identifiers of previously active contexts. This set
* may be empty. If this set is not empty, it must only contain
* instances of <code>String</code>. This set must be
* <code>null</code> if activeContextChanged is
* <code>false</code> and must not be null if
* activeContextChanged is <code>true</code>.
*/
public ContextManagerEvent(final ContextManager contextManager,
final String contextId, final boolean contextIdAdded,
final boolean activeContextsChanged,
final Set previouslyActiveContextIds) {
if (contextManager == null) {
throw new NullPointerException();
}
this.contextManager = contextManager;
this.contextId = contextId;
this.previouslyActiveContextIds = previouslyActiveContextIds;
if (contextIdAdded) {
changedValues |= CHANGED_CONTEXT_DEFINED;
}
if (activeContextsChanged) {
changedValues |= CHANGED_CONTEXTS_ACTIVE;
}
}
/**
* Returns the context identifier that was added or removed.
*
* @return The context identifier that was added or removed. This value may
* be <code>null</code> if no context identifier was added or
* removed.
*/
public final String getContextId() {
return contextId;
}
/**
* Returns the instance of the interface that changed.
*
* @return the instance of the interface that changed. Guaranteed not to be
* <code>null</code>.
*/
public final ContextManager getContextManager() {
return contextManager;
}
/**
* Returns the set of identifiers to previously active contexts.
*
* @return the set of identifiers to previously active contexts. This set
* may be empty. If this set is not empty, it is guaranteed to only
* contain instances of <code>String</code>. This set is
* guaranteed to be <code>null</code> if
* haveActiveContextChanged() is <code>false</code> and is
* guaranteed to not be <code>null</code> if
* haveActiveContextsChanged() is <code>true</code>.
*/
public final Set getPreviouslyActiveContextIds() {
return previouslyActiveContextIds;
}
/**
* Returns whether the active context identifiers have changed.
*
* @return <code>true</code> if the collection of active contexts changed;
* <code>false</code> otherwise.
*/
public final boolean isActiveContextsChanged() {
return ((changedValues & CHANGED_CONTEXTS_ACTIVE) != 0);
}
/**
* Returns whether the list of defined context identifiers has changed.
*
* @return <code>true</code> if the list of context identifiers has
* changed; <code>false</code> otherwise.
*/
public final boolean isContextChanged() {
return (contextId != null);
}
/**
* Returns whether the context identifier became defined. Otherwise, the
* context identifier became undefined.
*
* @return <code>true</code> if the context identifier became defined;
* <code>false</code> if the context identifier became undefined.
*/
public final boolean isContextDefined() {
return (((changedValues & CHANGED_CONTEXT_DEFINED) != 0) && (contextId != null));
}
}
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