bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/contexts/ContextLegacyWrapper.java

/*******************************************************************************
 * Copyright (c) 2005, 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.ui.internal.contexts;

import org.eclipse.core.commands.contexts.Context;
import org.eclipse.core.commands.contexts.ContextManager;
import org.eclipse.ui.contexts.IContext;
import org.eclipse.ui.contexts.IContextListener;
import org.eclipse.ui.contexts.NotDefinedException;
import org.eclipse.ui.internal.util.Util;

/**
 * This implements the old <code>IContext</code> interface based on the new
 * context implementation in <code>org.eclipse.ui.contexts</code>. This is a
 * wrapper.
 *
 * @since 3.1
 */
public class ContextLegacyWrapper implements IContext {

	/**
	 * The context manager that maintains the set of active contexts; must not be
	 * <code>null</code>.
	 */
	private final ContextManager contextManager;

	/**
	 * The wrapped instance of context. This value will never be <code>null</code>.
	 */
	private final Context wrappedContext;

	/**
	 * Constructs a new instance of <code>ContextWrapper</code>.
	 *
	 * @param context        The context to wrapper; must not be <code>null</code>.
	 * @param contextManager The context manager that maintains the set of active
	 *                       contexts; must not be <code>null</code>.
	 */
	public ContextLegacyWrapper(final Context context, final ContextManager contextManager) {
		if (context == null) {
			throw new NullPointerException("A wrapper cannot be created on a null context"); //$NON-NLS-1$
		}

		if (contextManager == null) {
			throw new NullPointerException("A wrapper cannot be created with a null manager"); //$NON-NLS-1$
		}

		wrappedContext = context;
		this.contextManager = contextManager;
	}

	@Override
	public void addContextListener(IContextListener contextListener) {
		final LegacyContextListenerWrapper wrapper = new LegacyContextListenerWrapper(contextListener, contextManager,
				this);
		wrappedContext.addContextListener(wrapper);

		/*
		 * We need to add the listener to the context manager as well, as only the
		 * manager advertises changes to the enabled state.
		 */
		contextManager.addContextManagerListener(wrapper);
	}

	@Override
	public int compareTo(Object o) {
		return Util.compare(wrappedContext, ((ContextLegacyWrapper) o).wrappedContext);
	}

	@Override
	public String getId() {
		return wrappedContext.getId();
	}

	@Override
	public String getName() throws NotDefinedException {
		try {
			return wrappedContext.getName();
		} catch (final org.eclipse.core.commands.common.NotDefinedException e) {
			throw new NotDefinedException(e);
		}
	}

	@Override
	public String getParentId() throws NotDefinedException {
		try {
			return wrappedContext.getParentId();
		} catch (final org.eclipse.core.commands.common.NotDefinedException e) {
			throw new NotDefinedException(e);
		}
	}

	@Override
	public boolean isDefined() {
		return wrappedContext.isDefined();
	}

	@Override
	public boolean isEnabled() {
		return contextManager.getActiveContextIds().contains(wrappedContext.getId());
	}

	@Override
	public void removeContextListener(IContextListener contextListener) {
		final LegacyContextListenerWrapper wrapper = new LegacyContextListenerWrapper(contextListener, contextManager,
				this);
		wrappedContext.removeContextListener(wrapper);
		contextManager.removeContextManagerListener(wrapper);
	}

}