/*
* Copyright (c) 1998, 1999, 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
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*/
package com.sun.tools.example.debug.bdi;
import com.sun.jdi.ThreadGroupReference;
import com.sun.jdi.ThreadReference;
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
*/
public class ThreadGroupIterator implements Iterator {
private final Stack<Iterator<ThreadGroupReference>> stack
= new Stack<Iterator<ThreadGroupReference>>();
public ThreadGroupIterator(List<ThreadGroupReference> tgl) {
push(tgl);
}
public ThreadGroupIterator(ThreadGroupReference tg) {
List<ThreadGroupReference> tgl = new ArrayList<ThreadGroupReference>();
tgl.add(tg);
push(tgl);
}
/*
ThreadGroupIterator() {
this(Env.vm().topLevelThreadGroups());
}
*/
private Iterator top() {
return (Iterator)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();
}
}
public boolean hasNext() {
return !stack.isEmpty();
}
public Object next() {
return nextThreadGroup();
}
public ThreadGroupReference nextThreadGroup() {
ThreadGroupReference tg = (ThreadGroupReference)top().next();
push(tg.threadGroups());
return tg;
}
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;
}
*/
}