1 /*
2 * $Id: IProgressMonitor.java,v 1.18 2011/06/16 09:29:42 jbmeslin Exp $
3 *
4 */
5 /*******************************************************************************
6 * Copyright (c) 2000, 2004 IBM Corporation and others.
7 * All rights reserved. This program and the accompanying materials
8 * are made available under the terms of the Eclipse Public License v1.0
9 * which accompanies this distribution, and is available at
10 * http://www.eclipse.org/legal/epl-v10.html
11 *
12 * Contributors:
13 * IBM Corporation - initial API and implementation
14 *******************************************************************************/
15 package org.rcfaces.core.progressMonitor;
16
17 /**
18 * The <code>IProgressMonitor</code> interface is implemented by objects that
19 * monitor the progress of an activity; the methods in this interface are
20 * invoked by code that performs the activity.
21 * <p>
22 * All activity is broken down into a linear sequence of tasks against which
23 * progress is reported. When a task begins, a <code>beginTask(String, int)
24 * </code>
25 * notification is reported, followed by any number and mixture of progress
26 * reports (<code>worked()</code>) and subtask notifications (<code>subTask(String)</code>).
27 * When the task is eventually completed, a <code>done()</code> notification
28 * is reported. After the <code>done()</code> notification, the progress
29 * monitor cannot be reused; i.e., <code>
30 * beginTask(String, int)</code> cannot
31 * be called again after the call to <code>done()</code>.
32 * </p>
33 * <p>
34 * A request to cancel an operation can be signaled using the
35 * <code>setCanceled</code> method. Operations taking a progress monitor are
36 * expected to poll the monitor (using <code>isCanceled</code>) periodically
37 * and abort at their earliest convenience. Operation can however choose to
38 * ignore cancelation requests.
39 * </p>
40 * <p>
41 * Since notification is synchronous with the activity itself, the listener
42 * should provide a fast and robust implementation. If the handling of
43 * notifications would involve blocking operations, or operations which might
44 * throw uncaught exceptions, the notifications should be queued, and the actual
45 * processing deferred (or perhaps delegated to a separate thread).
46 * </p>
47 * <p>
48 * Clients may implement this interface.
49 * </p>
50 */
51 public interface IProgressMonitor {
52
53 /**
54 * Constant indicating an unknown amount of work.
55 */
56 public final static int UNKNOWN = -1;
57
58 /**
59 * Notifies that the main task is beginning. This must only be called once
60 * on a given progress monitor instance.
61 *
62 * @param name
63 * the name (or description) of the main task
64 * @param totalWork
65 * the total number of work units into which the main task is
66 * been subdivided. If the value is <code>UNKNOWN</code> the
67 * implementation is free to indicate progress in a way which
68 * doesn't require the total number of work units in advance.
69 */
70 public void beginTask(String name, int totalWork);
71
72 /**
73 * Notifies that the work is done; that is, either the main task is
74 * completed or the user canceled it. This method may be called more than
75 * once (implementations should be prepared to handle this case).
76 */
77 public void done();
78
79 /**
80 * Internal method to handle scaling correctly. This method must not be
81 * called by a client. Clients should always use the method </code>worked(int)</code>.
82 *
83 * @param work
84 * the amount of work done
85 */
86 public void internalWorked(double work);
87
88 /**
89 * Returns whether cancelation of current operation has been requested.
90 * Long-running operations should poll to see if cancelation has been
91 * requested.
92 *
93 * @return <code>true</code> if cancellation has been requested, and
94 * <code>false</code> otherwise
95 * @see #setCanceled(boolean)
96 */
97 public boolean isCanceled();
98
99 /**
100 * Sets the cancel state to the given value.
101 *
102 * @param value
103 * <code>true</code> indicates that cancelation has been
104 * requested (but not necessarily acknowledged);
105 * <code>false</code> clears this flag
106 * @see #isCanceled()
107 */
108 public void setCanceled(boolean value);
109
110 /**
111 * Sets the task name to the given value. This method is used to restore the
112 * task label after a nested operation was executed. Normally there is no
113 * need for clients to call this method.
114 *
115 * @param name
116 * the name (or description) of the main task
117 * @see #beginTask(java.lang.String, int)
118 */
119 public void setTaskName(String name);
120
121 /**
122 * Notifies that a subtask of the main task is beginning. Subtasks are
123 * optional; the main task might not have subtasks.
124 *
125 * @param name
126 * the name (or description) of the subtask
127 */
128 public void subTask(String name);
129
130 /**
131 * Notifies that a given number of work unit of the main task has been
132 * completed. Note that this amount represents an installment, as opposed to
133 * a cumulative amount of work done to date.
134 *
135 * @param work
136 * the number of work units just completed
137 */
138 public void worked(int work);
139 }