GeoTiffDeadlockTest.java

package org.geotools.gce.geotiff;

import static org.junit.Assert.*;

import java.io.File;
import java.io.FilenameFilter;
import java.lang.management.ManagementFactory;
import java.lang.management.ThreadMXBean;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;

import org.geotools.test.TestData;
import org.junit.Test;

public class GeoTiffDeadlockTest {
    
    /**
     * Increase this value to get more threads than files
     */
    int multiplier = 1;
    
    @Test
    public void testForDeadlock() throws Exception {
        // grab all the test data files (but not those that contain known errors)
        final File dir = TestData.file(GeoTiffReaderTest.class, "");
        final File files[] = dir.listFiles(new FilenameFilter() {
            
            public boolean accept(File dir, String name) {
                if(name.startsWith("no_crs_no_envelope")) {
                    return false;
                }
                return true;
            }
        });
        final int numFiles = files.length;
        
        // prepare the loaders
        final AtomicInteger ai = new AtomicInteger(numFiles);

        // start them
        // System.out.println("Testing with " + numFiles + " files");
        final List<Thread> threads = new ArrayList<Thread>();
        final int total = numFiles * multiplier;
        //System.out.println("Testing with " + total + " threads");
        for (int index = 0; index < total; index++) {
            final File file = files[index % multiplier];
            Runnable testRunner = new Runnable() {
                public void run() {
                    try {
                        GeoTiffReader reader = new GeoTiffReader(file);
                        reader.read(null);
                    } catch (Exception e) {
                        throw new RuntimeException("Exception opening file " + file, e);
                    } finally {
                        ai.decrementAndGet();
                    }
                }
            };
            
            final Thread thread = new Thread(testRunner);
            thread.start();
            threads.add(thread);
        }

        // use jmx to do deadlock detection
        try {
            final ThreadMXBean mbean = ManagementFactory.getThreadMXBean();
            while (ai.get() > 0) {
                long[] deadlockedThreads = mbean.findMonitorDeadlockedThreads();
                if (deadlockedThreads != null && deadlockedThreads.length > 0) {
                    fail("Deadlock detected between the following threads: "
                            + Arrays.toString(deadlockedThreads));
                }
                // sleep for a bit
                Thread.currentThread().sleep(10);
            }
        } finally {
            // kill all the threads
            for (final Thread thread : threads) {
                if(thread.isAlive()) {
                    thread.interrupt();
                }
            }
        }
    }
}