Guavaライブラリのconcurrentパッケージの使い方 ref: http://qiita.com/mountcedar/items/e20251b811b491666d48

file0.java

URL[] topSites = null;
try {
    topSites = new URL[] {new URL("http://www.google.com")};
} catch (MalformedURLException e1) {
    e1.printStackTrace();
}

logger.debug("in main");
ListeningExecutorService pool = MoreExecutors.listeningDecorator(Executors.newFixedThreadPool(10));
for (final URL siteUrl : topSites) {
    final ListenableFuture<String> future = pool.submit(new Callable<String>() {
        @Override
        public String call() throws Exception {
            logger.debug("in call()");
            Thread.sleep(100);
            return siteUrl.toString();
        }
    });

    future.addListener(new Runnable() {
        @Override
        public void run() {
            try {
                final String contents = future.get();
                logger.debug("listener[1]: {}", contents);
                Thread.sleep(100);
            } catch (InterruptedException e) {
            } catch (ExecutionException e) {
            } finally {
                logger.debug("job completed.");
            }
        }
    }, pool);

    future.addListener(new Runnable() {
        @Override
        public void run() {
            try {
                final String contents = future.get();
                logger.debug("listener[2]: {}", contents);
                Thread.sleep(100);
            } catch (InterruptedException e) {
            } catch (ExecutionException e) {
            } finally {
                logger.debug("job completed.");
            }
        }
    }, pool);
}
try {
    Thread.sleep(300);
} catch (InterruptedException e) {
    e.printStackTrace();
}
pool.shutdownNow();

file0.txt

protected static Logger logger = LoggerFactory.getLogger(App.class);
public static void main (String[] args) {
URL[] topSites = null;
try {
    topSites = new URL[] {new URL("http://www.google.com")};
} catch (MalformedURLException e1) {
    e1.printStackTrace();
}

logger.debug("in main");
ListeningExecutorService pool = MoreExecutors.listeningDecorator(Executors.newFixedThreadPool(10));
for (final URL siteUrl : topSites) {
    final ListenableFuture<String> future = pool.submit(new Callable<String>() {
        @Override
        public String call() throws Exception {
            logger.debug("in call()");
            Thread.sleep(100);
            return siteUrl.toString();
        }
    });

    future.addListener(new Runnable() {
        @Override
        public void run() {
            try {
                final String contents = future.get();
                logger.debug("listener[1]: {}", contents);
                Thread.sleep(100);
            } catch (InterruptedException e) {
            } catch (ExecutionException e) {
            } finally {
                logger.debug("job completed.");
            }
        }
    }, pool);

    future.addListener(new Runnable() {
        @Override
        public void run() {
            try {
                final String contents = future.get();
                logger.debug("listener[2]: {}", contents);
                Thread.sleep(100);
            } catch (InterruptedException e) {
            } catch (ExecutionException e) {
            } finally {
                logger.debug("job completed.");
            }
        }
    }, pool);
}
try {
    Thread.sleep(300);
} catch (InterruptedException e) {
    e.printStackTrace();
}
pool.shutdownNow();

file1.txt

14:55:58.286 [main] DEBUG concurrent.App - in main
14:55:58.300 [pool-1-thread-1] DEBUG concurrent.App - in call()
14:55:58.401 [pool-1-thread-2] DEBUG concurrent.App - listener[1]: http://www.google.com
14:55:58.401 [pool-1-thread-3] DEBUG concurrent.App - listener[2]: http://www.google.com
14:55:58.502 [pool-1-thread-3] DEBUG concurrent.App - job completed.
14:55:58.502 [pool-1-thread-2] DEBUG concurrent.App -  job completed.

file2.java

    future.addListener(new Runnable() {
        @Override
        public void run() {
            try {
                final String contents = future.get();
                logger.debug("listener[2]: {}", contents);
                Thread.sleep(100);
            } catch (InterruptedException e) {
            } catch (ExecutionException e) {
            } finally {
                logger.debug("job completed.");
            }
        }
    }, MoreExecutors.sameThreadExecutor());

file2.txt

    future.addListener(new Runnable() {
        @Override
        public void run() {
            try {
                final String contents = future.get();
                logger.debug("listener[2]: {}", contents);
                Thread.sleep(100);
            } catch (InterruptedException e) {
            } catch (ExecutionException e) {
            } finally {
                logger.debug("job completed.");
            }
        }
    }, MoreExecutors.sameThreadExecutor());

file3.txt

15:14:42.126 [main] DEBUG concurrent.App - in main
15:14:42.141 [pool-1-thread-1] DEBUG concurrent.App - in call()
15:14:42.242 [pool-1-thread-1] DEBUG concurrent.App - listener[1]: http://www.google.com
15:14:42.343 [pool-1-thread-1] DEBUG concurrent.App - job completed.
15:14:42.343 [pool-1-thread-1] DEBUG concurrent.App - listener[2]: http://www.google.com
15:14:42.444 [pool-1-thread-1] DEBUG concurrent.App - job completed.

file4.java

ListeningExecutorService pool = MoreExecutors.listeningDecorator(Executors.newFixedThreadPool(10));

file5.java

final ListenableFuture<String> future = pool.submit(new Callable<String>() {
    @Override
    public String call() throws Exception {
        logger.debug("in call()");
        Thread.sleep(100);
        return siteUrl.toString();
    }
});

file6.java

    future.addListener(new Runnable() {
        @Override
        public void run() {
            try {
                final String contents = future.get();
                logger.debug("listener[1]: {}", contents);
                Thread.sleep(100);
            } catch (InterruptedException e) {
            } catch (ExecutionException e) {
            } finally {
                logger.debug("job completed.");
            }
        }
    }, pool);

file6.txt

    future.addListener(new Runnable() {
        @Override
        public void run() {
            try {
                final String contents = future.get();
                logger.debug("listener[1]: {}", contents);
                Thread.sleep(100);
            } catch (InterruptedException e) {
            } catch (ExecutionException e) {
            } finally {
                logger.debug("job completed.");
            }
        }
    }, pool);

file7.java

public class DataClowler implements Callable<String> {
    protected static Logger logger = LoggerFactory.getLogger(DataClowler.class);

    protected ListenableScheduledFuture future = null;
    protected ListeningScheduledExecutorService scheduler = null;
    protected ListeningExecutorService pool = null;
    protected static final int threadPoolNum = 10;
    protected long delay = 0;

    protected String uri = null;

    public DataClowler(String url) {
        this.scheduler = MoreExecutors.listeningDecorator(Executors.newScheduledThreadPool(threadPoolNum));
        this.pool = MoreExecutors.listeningDecorator(Executors.newFixedThreadPool(threadPoolNum));
        this.uri = url;
        this.delay = 2000; // msec
    }

    public String call () {
        try {
            String resource = Resources.toString(new URL(this.uri), Charsets.UTF_8);
            future = scheduler.schedule(this, this.delay, TimeUnit.MILLISECONDS);
            future.addListener(new Echo(future), this.pool);
            return resource;
        } catch (Exception e) {
            logger.error("Error: {}", e);
            return null;
        }
    }

    /**
     * タスクを開始(再開)する。
     */    
    public void start() {
        future = scheduler.schedule(this, this.delay, TimeUnit.MILLISECONDS);
        future.addListener(new DataClowler(core, future), this.pool);
    }

    /**
     * schedulerに登録したタスクを停止する。
     */
    public void stop() {
        if (future != null) future.cancel(true);
    }

    /**
     * schedulerをシャットダウンする
     */
    public void shutdown() {
        scheduler.shutdownNow();
    }
}

file8.java

public class Echo implements Runnable {
    protected ListenableScheduledFuture future = null;

    public Echo(ListenableScheduledFuture future) {
        this.future = future;
    }

    @Override
    public void run() {
        try {
            final String contents = (String)future.get();
            logger.debug("listener[1]: {}", contents);
            Thread.sleep(100);
        } catch (InterruptedException e) {
        } catch (ExecutionException e) {
        } finally {
            logger.debug("job completed.");
        }
   }
}