| /******************************************************************************* |
| * 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)); |
| } |
| } |