/*
 * Copyright 2005 The Apache Software Foundation.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at 
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software 
 * distributed under the License is distributed on an "AS IS" BASIS, 
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
 * See the License for the specific language governing permissions and 
 * limitations under the License.
 */

package org.apache.jdo.tck.api.persistencemanager;

import java.util.Iterator;
import java.util.Map;
import java.util.Set;

import javax.jdo.JDOUserException;
import javax.jdo.PersistenceManager;
import javax.jdo.PersistenceManagerFactory;
import javax.jdo.Transaction;

import org.apache.jdo.tck.pc.mylib.PCPoint;
import org.apache.jdo.tck.util.BatchTestRunner;
import org.apache.jdo.tck.util.ThreadExceptionHandler;
import org.apache.jdo.tck.util.RogueBarrier;

/**
 *<B>Title:</B> Thread Safe
 *<BR>
 *<B>Keywords:</B> multithreaded
 *<BR>
 *<B>Assertion ID:</B> A12.4-1.
 *<BR>
 *<B>Assertion Description: </B>
It is a requirement for all JDO implementations to be thread-safe. That is, the behavior of the implementation must be predictable in the presence of multiple application threads.  This assertion will generate multiple test cases to be evaluated.

 */
public class ThreadSafe extends PersistenceManagerTest {
    
    /** */
    private static final String ASSERTION_FAILED = 
        "Assertion A12.4-1 (ThreadSafe) failed: ";
    
    /**
     * The <code>main</code> is called when the class
     * is directly executed from the command line.
     * @param args The arguments passed to the program.
     */
    public static void main(String[] args) {
        BatchTestRunner.run(ThreadSafe.class);
    }

    private final int threadCount = 2;
    private final RogueBarrier barrier = new RogueBarrier(threadCount);
    private final ThreadExceptionHandler group = new ThreadExceptionHandler();
    private PersistenceManagerFactory pmf;
    private int successCount = 0;
    private int exceptionCount = 0;

    /** */
    public void testThreadSafe() throws Exception  {
        if(debug) logger.debug("\nSTART testThreadSafe");
        pmf = getPMF();
        
        // test thread-safety of PMF.getPersistenceManager():
        //   pmf.getPM(), pm.close() 
        final PCPoint[] nullPC = new PCPoint[threadCount];
        testConcurrent(nullPC, "Concurrent PMF.getPersistenceManager()",
                       threadCount);

        // test thread-safety of PMF.getPersistenceManager():
        //   pmf.getPM(), pm.makePersistent(private transient PC), pm.close() 
        final PCPoint[] localPC = new PCPoint[threadCount];
        for (int i = 0; i < threadCount; i++) {
            localPC[i] = new PCPoint(1,i);
        }
        testConcurrent(localPC, "Concurrent PMF.getPersistenceManager()"
                       + ".makePersistent()", threadCount);

        // test thread-safety of PM.makePersistent():
        //   pmf.getPM(), pm.makePersistent(shared transient PC), pm.close() 
        final PCPoint[] sharedPC = new PCPoint[threadCount];
        final PCPoint p1 = new PCPoint(3,3);
        for (int i = 0; i < threadCount; i++) {
            sharedPC[i] = p1;
        }
        testConcurrent(sharedPC, "Concurrent PM.makePersistent("
                       + "shared transient PC)", 1);
    }

    /** */
    public void testConcurrent(PCPoint[] pc, String header, int toSucceed) {
        // start threads with their pc instance
        final Thread[] threads = new Thread[threadCount];
        for (int i = 0; i < threadCount; i++) {
            Thread t = new Thread(group, new PMThread(pc[i]));
            t.setName("ThreadSafeID-" + i);
            threads[i] = t;
            t.start();
        }

        // wait for all threads to finish
        for (int i = 0; i < threadCount; i++) {
            while (true) {
                try {
                    threads[i].join();
                    break;
                } catch (InterruptedException e) { // swallow
                }
            }
        }

        checkResults(group, header, toSucceed);
    }

    /** */
    public synchronized void checkResults(ThreadExceptionHandler group,
                                          String header,
                                          int toSucceed) {
        // check unhandled exceptions
        final Set uncaught = group.getAllUncaughtExceptions();
        if ((uncaught != null) && !uncaught.isEmpty()) {
            StringBuffer report = new StringBuffer("Uncaught exceptions:\n");
            for (Iterator i = uncaught.iterator(); i.hasNext();) {
                Map.Entry next = (Map.Entry)i.next();
                Thread thread = (Thread)next.getKey();
                Throwable problem = (Throwable)next.getValue();
                report.append(header + ": Uncaught exception " + problem
                              + " in thread " + thread + "\n");
            }
            fail(ASSERTION_FAILED, report.toString());
            group.clear();
        }
        
        if (successCount != toSucceed) {
            fail(ASSERTION_FAILED, header + ": Incorrect number of "
                 + "\"succeeding\" threads; expected=" + toSucceed
                 + " found=" + successCount);
        }
        successCount = 0;
        
        final int toExcept = threadCount - toSucceed;
        if (exceptionCount != toExcept) {
            fail(ASSERTION_FAILED, header + ": Incorrect number of "
                 + "\"failing\" threads; expected=" + toExcept
                 + " found=" + exceptionCount);
        }
        exceptionCount = 0;
    }

    /** */
    protected synchronized void markSuccess() {
        logger.debug("[" + Thread.currentThread().getName() + "]: success");
        successCount++;
    }

    /** */
    protected synchronized void markExpectedException() {
        logger.debug("[" + Thread.currentThread().getName() + "]: expected exception");
        exceptionCount++;
    }

    /** */
    class PMThread implements Runnable {
        private final Object pc;

        /** */
        PMThread(PCPoint pc) {
            this.pc = pc;
        }

        /** */
        public void run() {
            ThreadSafe.this.logger.debug("[" + Thread.currentThread().getName()
                                         + "]: running");
            final PersistenceManager pm = pmf.getPersistenceManager();
            try {
                Transaction tx = pm.currentTransaction();
                tx.begin();
                if (pc != null) {
                    pm.makePersistent(pc);
                }
                tx.commit();
                markSuccess();
            } catch (JDOUserException ex) {
                markExpectedException();
            } finally {
                barrier.await();
                cleanupPM(pm);
            }
        }
    }
}