http://www.eclipse.org/platform: Commands (Eclipse Foundation) 
Copyright (c) 2003, 2015 IBM Corporation and others.
This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
    IBM Corporation - initial API and implementation

/*******************************************************************************
 * Copyright (c) 2003, 2015 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.core.commands.contexts;

import java.util.Set;

import org.eclipse.core.commands.common.AbstractBitSetEvent;



An event indicating that the set of defined context identifiers has changed.



See Also:
Since:3.1
/**
 * <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.

/**
	 * 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.

/**
	 * 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.

/**
	 * 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.

/**
	 * 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 null.

/**
	 * 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<String> previouslyActiveContextIds;

	
Creates a new instance of this class.

Params:
  • contextManager – 
           the instance of the interface that changed; must not be
           null.
  • contextId – 
           The context identifier that was added or removed; may be
           null if the active contexts are changing.
  • contextIdAdded – 
           Whether the context identifier became defined (otherwise, it
           became undefined).
  • activeContextsChanged – 
           Whether the list of active contexts has changed.
  • 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 String. This set must be
           null if activeContextChanged is
           false and must not be null if
           activeContextChanged is true.
/**
	 * 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>.
	 */
	@SuppressWarnings("unchecked")
	public ContextManagerEvent(final ContextManager contextManager,
			final String contextId, final boolean contextIdAdded,
			final boolean activeContextsChanged,
			@SuppressWarnings("rawtypes") 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.

Returns:The context identifier that was added or removed. This value may
        be null if no context identifier was added or
        removed.
/**
	 * 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.

Returns:the instance of the interface that changed. Guaranteed not to be
        null.
/**
	 * 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.

Returns: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 String. This set is
        guaranteed to be null if
        haveActiveContextChanged() is false and is
        guaranteed to not be null if
        haveActiveContextsChanged() is true.
/**
	 * 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>.
	 */
	@SuppressWarnings("rawtypes")
	public final Set getPreviouslyActiveContextIds() {
		return previouslyActiveContextIds;
	}

	
Returns whether the active context identifiers have changed.

Returns:true if the collection of active contexts changed;
        false otherwise.
/**
	 * 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.

Returns:true if the list of context identifiers has
        changed; false otherwise.
/**
	 * 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.

Returns:true if the context identifier became defined;
        false if the context identifier became undefined.
/**
	 * 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));
	}
}