IHandler


1   /*******************************************************************************
2    * Copyright (c) 2003, 2005 IBM Corporation and others.
3    * All rights reserved. This program and the accompanying materials
4    * are made available under the terms of the Eclipse Public License v1.0
5    * which accompanies this distribution, and is available at
6    * http://www.eclipse.org/legal/epl-v10.html
7    *
8    * Contributors:
9    *     IBM Corporation - initial API and implementation
10   *******************************************************************************/
11  package org.eclipse.ui.commands;
12  
13  import java.util.Map  ;
14  
15  /**
16   * A handler is the pluggable piece of a command that handles execution. Each
17   * command can have zero or more handlers associated with it (in general), of
18   * which only one will be active at any given moment in time. When the command
19   * is asked to execute, it will simply pass that request on to its active
20   * handler, if any.
21   * <p>
22   * This interface is not intended to be extended by clients.
23   * </p>
24   * 
25   * @since 3.0
26   * @deprecated Please use the "org.eclipse.core.commands" plug-in instead.
27   * @see org.eclipse.core.commands.IHandler
28   */
29  public interface IHandler {
30  
31      /**
32       * Registers an instance of <code>IHandlerListener</code> to listen for
33       * changes to properties of this instance.
34       * 
35       * @param handlerListener
36       *            the instance to register. Must not be <code>null</code>. If
37       *            an attempt is made to register an instance which is already
38       *            registered with this instance, no operation is performed.
39       */
40      void addHandlerListener(IHandlerListener handlerListener);
41  
42      /**
43       * Disposes of this handler. This method is run once when the object is no
44       * longer referenced. This can be used as an opportunity to unhook listeners
45       * from other objects.
46       */
47      public void dispose();
48  
49      /**
50       * Executes with the map of parameter values by name.
51       * 
52       * @param parameterValuesByName
53       *            the map of parameter values by name. Reserved for future use,
54       *            must be <code>null</code>.
55       * @return the result of the execution. Reserved for future use, must be
56       *         <code>null</code>.
57       * @throws ExecutionException
58       *             if an exception occurred during execution.
59       */
60      Object   execute(Map   parameterValuesByName) throws ExecutionException;
61  
62      /**
63       * Returns the map of attribute values by name.
64       * <p>
65       * Notification is sent to all registered listeners if this property
66       * changes.
67       * </p>
68       * 
69       * @return the map of attribute values by name. This map may be empty, but
70       *         is guaranteed not to be <code>null</code>. If this map is not
71       *         empty, its collection of keys is guaranteed to only contain
72       *         instances of <code>String</code>.
73       */
74      Map   getAttributeValuesByName();
75  
76      /**
77       * Unregisters an instance of <code>IPropertyListener</code> listening for
78       * changes to properties of this instance.
79       * 
80       * @param handlerListener
81       *            the instance to unregister. Must not be <code>null</code>.
82       *            If an attempt is made to unregister an instance which is not
83       *            already registered with this instance, no operation is
84       *            performed.
85       */
86      void removeHandlerListener(IHandlerListener handlerListener);
87  }
88
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