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1   /*
2    * Copyright (c) 1998, 2013, Oracle and/or its affiliates. All rights reserved.
3    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4    *
5    * This code is free software; you can redistribute it and/or modify it
6    * under the terms of the GNU General Public License version 2 only, as
7    * published by the Free Software Foundation.  Oracle designates this
8    * particular file as subject to the "Classpath" exception as provided
9    * by Oracle in the LICENSE file that accompanied this code.
10   *
11   * This code is distributed in the hope that it will be useful, but WITHOUT
12   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14   * version 2 for more details (a copy is included in the LICENSE file that
15   * accompanied this code).
16   *
17   * You should have received a copy of the GNU General Public License version
18   * 2 along with this work; if not, write to the Free Software Foundation,
19   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20   *
21   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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24   */
25  
26  package com.sun.jdi;
27  
28  import java.util.List;
29  
30  /**
31   * A thread group object from the target VM.
32   * A ThreadGroupReference is an {@link ObjectReference} with additional
33   * access to threadgroup-specific information from the target VM.
34   *
35   * @author Robert Field
36   * @author Gordon Hirsch
37   * @author James McIlree
38   * @since  1.3
39   */
40  @jdk.Exported
41  public interface ThreadGroupReference extends ObjectReference {
42  
43      /**
44       * Returns the name of this thread group.
45       *
46       * @return the string containing the thread group name.
47       */
48      String name();
49  
50      /**
51       * Returns the parent of this thread group.
52       *
53       * @return a {@link ThreadGroupReference} mirroring the parent of this
54       * thread group in the target VM, or null if this is a top-level
55       * thread group.
56       */
57      ThreadGroupReference parent();
58  
59      /**
60       * Suspends all threads in this thread group. Each thread
61       * in this group and in all of its subgroups will be
62       * suspended as described in {@link ThreadReference#suspend}.
63       * This is not guaranteed to be an atomic
64       * operation; if the target VM is not interrupted at the time
65       * this method is
66       * called, it is possible that new threads will be created
67       * between the time that threads are enumerated and all of them
68       * have been suspended.
69       * @throws VMCannotBeModifiedException if the VirtualMachine is read-only - see {@link VirtualMachine#canBeModified()}.
70       */
71      void suspend();
72  
73      /**
74       * Resumes all threads in this thread group. Each thread
75       * in this group and in all of its subgroups will be
76       * resumed as described in {@link ThreadReference#resume}.
77       * @throws VMCannotBeModifiedException if the VirtualMachine is read-only - see {@link VirtualMachine#canBeModified()}.
78       */
79      void resume();
80  
81      /**
82       * Returns a List containing a {@link ThreadReference} for each live thread
83       * in this thread group. Only the live threads in this immediate thread group
84       * (and not its subgroups) are returned.  A thread is alive if it
85       * has been started and has not yet been stopped.
86       *
87       * @return a List of {@link ThreadReference} objects mirroring the
88       * live threads from this thread group in the target VM.
89       */
90      List<ThreadReference> threads();
91  
92      /**
93       * Returns a List containing each active {@link ThreadGroupReference} in this
94       * thread group. Only the active thread groups in this immediate thread group
95       * (and not its subgroups) are returned.
96       * See <a href="{@docRoot}/../../../../api/java/lang/ThreadGroup.html">java.lang.ThreadGroup</a>
97       * for information about 'active' ThreadGroups.
98       * @return a List of {@link ThreadGroupReference} objects mirroring the
99       * active thread groups from this thread group in the target VM.
100      */
101     List<ThreadGroupReference> threadGroups();
102 }