Java Reference
In-Depth Information
Example 4−2: ThreadLister.java (continued)
private static void printThreadInfo(PrintWriter out, Thread t,
String indent) {
if (t == null) return;
out.println(indent + "Thread: " + t.getName() +
" Priority: " + t.getPriority() +
(t.isDaemon()?" Daemon":"") +
(t.isAlive()?"":" Not Alive"));
}
/** Display info about a thread group and its threads and groups */
private static void printGroupInfo(PrintWriter out, ThreadGroup g,
String indent) {
if (g == null) return;
int num_threads = g.activeCount();
int num_groups = g.activeGroupCount();
Thread[] threads = new Thread[num_threads];
ThreadGroup[] groups = new ThreadGroup[num_groups];
g.enumerate(threads, false);
g.enumerate(groups, false);
out.println(indent + "Thread Group: " + g.getName() +
" Max Priority: " + g.getMaxPriority() +
(g.isDaemon()?" Daemon":""));
for(int i = 0; i < num_threads; i++)
printThreadInfo(out, threads[i], indent + "
");
for(int i = 0; i < num_groups; i++)
printGroupInfo(out, groups[i], indent + "
");
}
/** Find the root thread group and list it recursively */
public static void listAllThreads(PrintWriter out) {
ThreadGroup current_thread_group;
ThreadGroup root_thread_group;
ThreadGroup parent;
// Get the current thread group
current_thread_group = Thread.currentThread().getThreadGroup();
// Now go find the root thread group
root_thread_group = current_thread_group;
parent = root_thread_group.getParent();
while(parent != null) {
root_thread_group = parent;
parent = parent.getParent();
}
// And list it, recursively
printGroupInfo(out, root_thread_group, "");
}
/**
* The main() method create a simple graphical user interface to display
* the threads in. This allows us to see the "event dispatch thread" used
* by AWT and Swing.
**/
public static void main(String[] args) {
