DumpThreadsOnErrorRule.java

/*
 *  Copyright 2009, Mahmood Ali.
 *  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions are
 *  met:
 *
 *    * Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *    * Redistributions in binary form must reproduce the above
 *      copyright notice, this list of conditions and the following disclaimer
 *      in the documentation and/or other materials provided with the
 *      distribution.
 *    * Neither the name of Mahmood Ali. nor the names of its
 *      contributors may be used to endorse or promote products derived from
 *      this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 *  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 *  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 *  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 *  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 *  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package com.notnoop.apns.utils.junit;


import org.junit.rules.TestRule;
import org.junit.runner.Description;
import org.junit.runners.model.Statement;

import java.util.Map;

public class DumpThreadsOnErrorRule implements TestRule {

    @Override
    public Statement apply(Statement base, Description description) {
        return new DumpThreadsStatement(base);
    }

    private static class DumpThreadsStatement extends Statement {

        private final Statement base;

        private DumpThreadsStatement(Statement base) {
            this.base = base;
        }

        @Override
        public void evaluate() throws Throwable {
            try {
                base.evaluate();
            } catch (Throwable t) {
                dumpAllThreads();
                throw t;
            }
        }

        private void dumpAllThreads() {
            Map liveThreads = Thread.getAllStackTraces();
            for (Object o : liveThreads.keySet()) {
                Thread key = (Thread) o;
                System.err.println("\nThread " + key.getName());
                StackTraceElement[] trace = (StackTraceElement[]) liveThreads.get(key);
                for (StackTraceElement aTrace : trace) {
                    System.err.println("\tat " + aTrace);
                }
            }
        }
    }
}