/*******************************************************************************
 * Copyright (c) 2000, 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.contexts;

import java.util.SortedSet;

/**
 * <p>
 * A context manager tracks the sets of defined and enabled contexts within the
 * application. The manager sends notification events to listeners when these
 * sets change. It is also possible to retrieve any given context with its
 * identifier.
 * </p>
 * <p>
 * This interface is not intended to be extended or implemented by clients.
 * </p>
 *
 * @since 3.0
 * @deprecated Please use the "org.eclipse.core.commands" plug-in instead.
 * @see org.eclipse.core.commands.contexts.ContextManager
 * @noimplement This interface is not intended to be implemented by clients.
 */
@Deprecated
public interface IContextManager {

	/**
	 * Registers an instance of <code>IContextManagerListener</code> to listen for
	 * changes to properties of this instance.
	 *
	 * @param contextManagerListener the instance to register. Must not be
	 *                               <code>null</code>. If an attempt is made to
	 *                               register an instance which is already
	 *                               registered with this instance, no operation is
	 *                               performed.
	 */
	void addContextManagerListener(IContextManagerListener contextManagerListener);

	/**
	 * Returns an instance of <code>IContext</code> given an identifier.
	 *
	 * @param contextId an identifier. Must not be <code>null</code>
	 * @return an instance of <code>IContext</code>.
	 */
	IContext getContext(String contextId);

	/**
	 * Returns the set of identifiers to defined contexts. The set is sorted by the
	 * depth of the context within the tree of contexts. So, for example, a child
	 * context will always appear before its parent.
	 * <p>
	 * Notification is sent to all registered listeners if this property changes.
	 * </p>
	 *
	 * @return the set of identifiers to defined contexts. This set may be empty,
	 *         but is guaranteed not to be <code>null</code>. If this set is not
	 *         empty, it is guaranteed to only contain instances of
	 *         <code>String</code>.
	 */
	SortedSet getDefinedContextIds();

	/**
	 * Returns the set of identifiers to enabled contexts. The set is sorted by the
	 * depth of the context within the tree of contexts. So, for example, a child
	 * context will always appear before its parent.
	 * <p>
	 * Notification is sent to all registered listeners if this property changes.
	 * </p>
	 *
	 * @return the set of identifiers to enabled contexts. This set may be empty,
	 *         but is guaranteed not to be <code>null</code>. If this set is not
	 *         empty, it is guaranteed to only contain instances of
	 *         <code>String</code>.
	 */
	SortedSet getEnabledContextIds();

	/**
	 * Unregisters an instance of <code>IContextManagerListener</code> listening for
	 * changes to properties of this instance.
	 *
	 * @param contextManagerListener the instance to unregister. Must not be
	 *                               <code>null</code>. If an attempt is made to
	 *                               unregister an instance which is not already
	 *                               registered with this instance, no operation is
	 *                               performed.
	 */
	void removeContextManagerListener(IContextManagerListener contextManagerListener);
}
