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Java > Open Source Codes > org > eclipse > ui > progress > IDeferredWorkbenchAdapter


1 /*******************************************************************************
2  * Copyright (c) 2000, 2006 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.progress;
12
13 import org.eclipse.core.runtime.IProgressMonitor;
14 import org.eclipse.core.runtime.jobs.ISchedulingRule;
15 import org.eclipse.ui.model.IWorkbenchAdapter;
16
17 /**
18  * This adapter interface provides support for lazy initialization of UI workbench elements
19  * that are displayed visually. This adapter is used with an associated deferred content provider.
20  *
21  * @see DeferredTreeContentManager
22  * @since 3.0
23  */
24 public interface IDeferredWorkbenchAdapter extends IWorkbenchAdapter {
25
26     /**
27      * Called by a job run in a separate thread to fetch the children of this adapter.
28      * The adapter should in return notify of new children via the collector.
29      * This is generally used when a content provider is getting elements.
30      * <p>
31      * It is good practice to check the passed in monitor for cancellation. This will
32      * provide good responsiveness for cancellation requests made by the user.
33      * </p>
34      *
35      * @param object the object to fetch the children for
36      * @param collector the collector to notify about new children. Should not
37      * be <code>null</code>.
38      * @param monitor a progress monitor that will never be <code>null<code> to
39      * support reporting and cancellation.
40      */
41     public void fetchDeferredChildren(Object JavaDoc object,
42             IElementCollector collector, IProgressMonitor monitor);
43
44     /**
45      * Returns whether this adapter may have children. This is an optimized method
46      * used by content providers to allow showing the [+] expand icon without having
47      * yet fetched the children for the element.
48      * <p>
49      * If <code>false</code> is returned, then the content provider may assume
50      * that this adapter has no children. If <code>true</code> is returned,
51      * then the job manager may assume that this adapter may have children.
52      * <p>
53      *
54      * @return <code>true</code>if the adapter may have childen, and <code>false</code>
55      * otherwise.
56      */
57     public boolean isContainer();
58
59     /**
60      * Returns the rule used to schedule the deferred fetching of children for this adapter.
61      *
62      * @param object the object whose children are being fetched
63      * @return the scheduling rule. May be <code>null</code>.
64      * @see org.eclipse.core.runtime.jobs.Job#setRule(ISchedulingRule)
65      */
66     public ISchedulingRule getRule(Object JavaDoc object);
67 }
68
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