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Java > Open Source Codes > org > eclipse > debug > core > commands > IDebugCommandHandler


1 /*******************************************************************************
2  * Copyright (c) 2006, 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 package org.eclipse.debug.core.commands;
12
13
14
15 /**
16  * Handles a command for a debugger. Specific command handlers extend this interface.
17  * <p>
18  * The debug platform provides actions for common debug commands that operate against
19  * these handler interfaces. For example, the platform provides a terminate action that
20  * operates on the active debug context (selected element in the debug view). The action
21  * delegates to the active context's {@link ITerminateHandler} implementation to update
22  * its enabled state and execute the command. Debug model elements may implement supported
23  * command handler interfaces directly or provide them as adapters. The debug platform
24  * provides implementations of handlers for standard debug models.
25  * </p>
26  * <p>
27  * Clients are not intended to implement this interface directly. Clients may
28  * implement specific command handler interfaces that extend this interface.
29  * </p>
30  * @see org.eclipse.core.runtime.IAdaptable
31  * @see IDisconnectHandler
32  * @see IDropToFrameHandler
33  * @see IResumeHandler
34  * @see IStepFiltersHandler
35  * @see IStepIntoHandler
36  * @see IStepOverHandler
37  * @see IStepReturnHandler
38  * @see ISuspendHandler
39  * @see ITerminateHandler
40  * @since 3.3
41  */
42 public interface IDebugCommandHandler {
43     
44     /**
45      * Determines whether this handler can execute on the elements specified
46      * in the given request by reporting enabled state to the request.
47      * <p>
48      * Implementations must be non-blocking and may respond asynchronously to the
49      * given request. Errors can reported by setting an appropriate status
50      * on the given request. A request can be canceled by this handler or caller.
51      * A <code>null</code> status is equivalent to an OK status.
52      * When a request succeeds, fails, or is canceled, implementations must call
53      * <code>done()</code> on the given request.
54      * </p>
55      * <p>
56      * Clients are expected to poll the request (using <code>isCanceled</code>)
57      * periodically and abort at their earliest convenience calling <code>done()</code>
58      * on the request.
59      * </p>
60      * @param request specifies elements to operate on and collects enabled state
61      */
62     public void canExecute(IEnabledStateRequest request);
63     
64     /**
65      * Executes this command on the elements specified in the given request
66      * reporting status to the given request and returns whether this handler should
67      * remain enabled while the command is executing.
68      * <p>
69      * Implementations must be non-blocking and may respond asynchronously to the
70      * given request. Errors can reported by setting an appropriate status
71      * on the given request. A request can be canceled by this handler or the caller.
72      * A <code>null</code> status is equivalent to an OK status. When a request is
73      * complete, has encountered an error, or cancelled, implementations must call
74      * <code>done()</code> on the given collector.
75      * </p>
76      * <p>
77      * Handlers are expected to poll the request (using <code>isCanceled</code>)
78      * periodically and abort at their earliest convenience calling <code>done()</code>
79      * on the request.
80      * </p>
81      * @param request specifies elements to operate on and collects execution status
82      * @return whether this handler remains enabled while command is executing
83      */
84     public boolean execute(IDebugCommandRequest request);
85
86 }
87
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