org.aspectj.runtime.internal.cflowstack.ThreadStackImpl11 Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of aspectjweaver Show documentation

The AspectJ weaver applies aspects to Java classes. It can be used as a Java agent in order to apply load-time weaving (LTW) during class-loading and also contains the AspectJ runtime classes.

There is a newer version: 1.9.22.1

Show newest version

/* *******************************************************************
 * Copyright (c) 2004 IBM Corporation
 *
 * All rights reserved.
 * This program and the accompanying materials are made available
 * under the terms of the Eclipse Public License v 2.0
 * which accompanies this distribution and is available at
 * https://www.eclipse.org/org/documents/epl-2.0/EPL-2.0.txt
 *
 * Contributors:
 *    Andy Clement     initial implementation
 * 					   Copied from bits of original CFlowStack
 * ******************************************************************/
package org.aspectj.runtime.internal.cflowstack;

import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Stack;

public class ThreadStackImpl11 implements ThreadStack {
	private Hashtable stacks = new Hashtable<>();
	private Thread cached_thread;
	private Stack cached_stack;
	private int change_count = 0;
	private static final int COLLECT_AT = 20000;
	private static final int MIN_COLLECT_AT = 100;

	public synchronized Stack getThreadStack() {
		if (Thread.currentThread() != cached_thread) {
			cached_thread = Thread.currentThread();
			cached_stack = (Stack)stacks.get(cached_thread);
			if (cached_stack == null) {
				cached_stack = new Stack<>();
				stacks.put(cached_thread, cached_stack);
			}
			change_count++;
			// Collect more often if there are many threads, but not *too* often
			int size = Math.max(1, stacks.size()); // should be >1 b/c always live threads, but...
			if (change_count > Math.max(MIN_COLLECT_AT, COLLECT_AT/size)) {
				Stack dead_stacks = new Stack<>();
				for (Enumeration e = stacks.keys(); e.hasMoreElements(); ) {
					Thread t = e.nextElement();
					if (!t.isAlive()) dead_stacks.push(t);
				}
				for (Enumeration e = dead_stacks.elements(); e.hasMoreElements(); ) {
					Thread t = e.nextElement();
					stacks.remove(t);
				}
				change_count = 0;
			}
		}
		return cached_stack;
	}

	public void removeThreadStack() {
		// TODO
	}

}