| /* |
| * Copyright (c) 1998, 2011, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| /* |
| * This source code is provided to illustrate the usage of a given feature |
| * or technique and has been deliberately simplified. Additional steps |
| * required for a production-quality application, such as security checks, |
| * input validation and proper error handling, might not be present in |
| * this sample code. |
| */ |
| |
| |
| package com.sun.tools.example.debug.tty; |
| |
| import com.sun.jdi.ThreadGroupReference; |
| import java.util.List; |
| import java.util.Stack; |
| import java.util.ArrayList; |
| import java.util.Iterator; |
| |
| /** |
| * Descend the tree of thread groups. |
| * @author Robert G. Field |
| */ |
| class ThreadGroupIterator implements Iterator<ThreadGroupReference> { |
| private final Stack<Iterator<ThreadGroupReference>> stack = new Stack<Iterator<ThreadGroupReference>>(); |
| |
| ThreadGroupIterator(List<ThreadGroupReference> tgl) { |
| push(tgl); |
| } |
| |
| ThreadGroupIterator(ThreadGroupReference tg) { |
| List<ThreadGroupReference> tgl = new ArrayList<ThreadGroupReference>(); |
| tgl.add(tg); |
| push(tgl); |
| } |
| |
| ThreadGroupIterator() { |
| this(Env.vm().topLevelThreadGroups()); |
| } |
| |
| private Iterator<ThreadGroupReference> top() { |
| return stack.peek(); |
| } |
| |
| /** |
| * The invariant in this class is that the top iterator |
| * on the stack has more elements. If the stack is |
| * empty, there is no top. This method assures |
| * this invariant. |
| */ |
| private void push(List<ThreadGroupReference> tgl) { |
| stack.push(tgl.iterator()); |
| while (!stack.isEmpty() && !top().hasNext()) { |
| stack.pop(); |
| } |
| } |
| |
| @Override |
| public boolean hasNext() { |
| return !stack.isEmpty(); |
| } |
| |
| @Override |
| public ThreadGroupReference next() { |
| return nextThreadGroup(); |
| } |
| |
| public ThreadGroupReference nextThreadGroup() { |
| ThreadGroupReference tg = top().next(); |
| push(tg.threadGroups()); |
| return tg; |
| } |
| |
| @Override |
| public void remove() { |
| throw new UnsupportedOperationException(); |
| } |
| |
| static ThreadGroupReference find(String name) { |
| ThreadGroupIterator tgi = new ThreadGroupIterator(); |
| while (tgi.hasNext()) { |
| ThreadGroupReference tg = tgi.nextThreadGroup(); |
| if (tg.name().equals(name)) { |
| return tg; |
| } |
| } |
| return null; |
| } |
| |
| } |