IFocusService


1   /*******************************************************************************
2    * Copyright (c) 2007 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  
12  package org.eclipse.ui.swt;
13  
14  import org.eclipse.swt.widgets.Control;
15  
16  /**
17   * Tracks focusGained and focusLost events for a Control registered with this
18   * service, and provides the control and its registered ID as variables to the
19   * application evaluation context for evaluation be the various services.
20   * <p>
21   * This service provides 2 variables, activeFocusControl (a Control) and
22   * activeFocusControlId (the ID registered with the service).
23   * </p>
24   * <p>
25   * You can use this service to provide default cut/copy/paste/selectAll for
26   * specific text controls outside of the normal workbench part lifecycle, like a
27   * control contributed to the trim. For example:
28   * </p>
29   * <p>
30   * 
31   * <pre>
32   * &lt;handler
33   *      class=&quot;org.eclipse.ui.internal.handlers.WidgetMethodHandler:paste&quot;
34   *      commandId=&quot;org.eclipse.ui.edit.paste&quot;&gt;
35   *   &lt;activeWhen&gt;
36   *      &lt;with variable=&quot;activeFocusControlId&quot;&gt;
37   *         &lt;equals value=&quot;org.eclipse.ui.tests.focusText&quot;/&gt;
38   *      &lt;/with&gt;
39   *   &lt;/activeWhen&gt;
40   * &lt;/handler&gt;
41   * </pre>
42   * 
43   * </p>
44   * 
45   * @see org.eclipse.ui.ISources
46   * @since 3.3
47   */
48  public interface IFocusService {
49      /**
50       * Use the value to provide default copy behaviour in a handler element
51       * class attribute.
52       */
53      public static final String   COPY_HANDLER = "org.eclipse.ui.internal.handlers.WidgetMethodHandler:copy"; //$NON-NLS-1$
54  
55      /**
56       * Use the value to provide default paste behaviour in a handler element
57       * class attribute.
58       */
59      public static final String   PASTE_HANDLER = "org.eclipse.ui.internal.handlers.WidgetMethodHandler:paste"; //$NON-NLS-1$
60  
61      /**
62       * Use the value to provide default cut behaviour in a handler element class
63       * attribute.
64       */
65      public static final String   CUT_HANDLER = "org.eclipse.ui.internal.handlers.WidgetMethodHandler:cut"; //$NON-NLS-1$
66  
67      /**
68       * Use the value to provide default select all behaviour in a handler
69       * element class attribute.
70       */
71      public static final String   SELECT_ALL_HANDLER = "org.eclipse.ui.internal.handlers.SelectAllHandler"; //$NON-NLS-1$
72  
73      /**
74       * A Control for which the service will track focus. When in focus, this
75       * Control and its ID will be provided as variables to core expressions for
76       * the various services, as activeFocusControl and activeFocusControlId
77       * respectively.
78       * <p>
79       * A control must only be registered once, but different controls can be
80       * registered with the same ID. Expressions evaluated against the
81       * activeFocusControlId would then be true for all of the controls thus
82       * registered.
83       * </p>
84       * <p>
85       * We will remove ourselves as a listener when the Control is disposed.
86       * </p>
87       * 
88       * @param control
89       *            the control. Must not be <code>null</code>. If the control
90       *            is already registered with this service this call is a no-op.
91       * @param id
92       *            an ID for this control. Must not be <code>null</code>.
93       */
94      public void addFocusTracker(Control control, String   id);
95  
96      /**
97       * No longer track focus events for this control. Use this method when the
98       * control should no longer be tracked, but is not disposed.
99       * 
100      * @param control
101      *            the control registered with the service. Must not be
102      *            <code>null</code>.
103      */
104     public void removeFocusTracker(Control control);
105 }
106
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