Examples of java.util.concurrent.Exchanger

java.util.concurrent.Exchanger
A synchronization point at which threads can pair and swap elements within pairs. Each thread presents some object on entry to the {@link #exchange exchange} method, matches with a partner thread,and receives its partner's object on return. An Exchanger may be viewed as a bidirectional form of a {@link SynchronousQueue}. Exchangers may be useful in applications such as genetic algorithms and pipeline designs.
Sample Usage: Here are the highlights of a class that uses an {@code Exchanger}to swap buffers between threads so that the thread filling the buffer gets a freshly emptied one when it needs it, handing off the filled one to the thread emptying the buffer.
```
  {@code}class FillAndEmpty  Exchanger exchanger = new Exchanger(); DataBuffer initialEmptyBuffer = ... a made-up type DataBuffer initialFullBuffer = ... class FillingLoop implements Runnable { public void run() { DataBuffer currentBuffer = initialEmptyBuffer; try { while (currentBuffer != null) { addToBuffer(currentBuffer); if (currentBuffer.isFull()) currentBuffer = exchanger.exchange(currentBuffer); } } catch (InterruptedException ex) { ... handle ... } } } class EmptyingLoop implements Runnable { public void run() { DataBuffer currentBuffer = initialFullBuffer; try { while (currentBuffer != null) { takeFromBuffer(currentBuffer); if (currentBuffer.isEmpty()) currentBuffer = exchanger.exchange(currentBuffer); } } catch (InterruptedException ex) { ... handle ...} } } void start() { new Thread(new FillingLoop()).start(); new Thread(new EmptyingLoop()).start(); } }}
```
Memory consistency effects: For each pair of threads that successfully exchange objects via an {@code Exchanger}, actions prior to the {@code exchange()} in each threadhappen-before those subsequent to a return from the corresponding {@code exchange()}in the other thread. @since 1.5 @author Doug Lea and Bill Scherer and Michael Scott @param < V> The type of objects that may be exchanged

                target = endpoint.getQueue() + "/t=" + endpoint.getConfiguration().getWaitTimeMs();
            } else {
                target = endpoint.getQueue();
            }


            @SuppressWarnings("rawtypes")
            Exchanger exchanger = null;
            while (isRunAllowed() && !shutdownPending) {
                if (concurrent) {
                    // Wait until an exchanger is available, indicating that a
                    // handler thread is ready to handle the next request.
                    // Don't read from kestrel until we know a handler is ready.
                    try {
                        exchanger = exchangerQueue.take();
                    } catch (InterruptedException e) {
                        if (log.isDebugEnabled()) {
                            log.debug("Interrupted, are we stopping? {}", isStopping() || isStopped());
                        }
                        continue;
                    }


                    // We have the exchanger, so there's a handler thread ready
                    // to handle whatever we may read...so read the next object
                    // from the queue.
                }


                // Poll kestrel until we get an object back
                Object value = null;
                while (isRunAllowed() && !shutdownPending) {
                    log.trace("Polling {}", target);
                    try {
                        value = memcachedClient.get(target);
                        if (value != null) {
                            break;
                        }
                    } catch (Exception e) {
                        if (isRunAllowed() && !shutdownPending) {
                            getExceptionHandler().handleException("Failed to get object from kestrel", e);
                        }
                    }


                    // We didn't get a value back from kestrel
                    if (isRunAllowed() && !shutdownPending) {
                        if (endpoint.getConfiguration().getWaitTimeMs() > 0) {
                            // Kestrel did the blocking for us
                        } else {
                            // We're doing non-blocking get, so in between we
                            // should at least sleep some short period of time
                            // so this loop doesn't go nuts so tightly.
                            try {
                                Thread.sleep(100);
                            } catch (InterruptedException ignored) {
                            }
                        }
                    }
                }


                log.trace("Got object from {}", target);


                if (concurrent) {
                    // Pass the object to the handler thread via the exchanger.
                    // The handler will take it from there.
                    try {
                        exchanger.exchange(value);
                    } catch (InterruptedException e) {
                        if (log.isDebugEnabled()) {
                            log.debug("Interrupted, are we stopping? {}", isStopping() || isStopped());
                        }
                        continue;

View Full Code Here

                target = endpoint.getQueue() + "/t=" + endpoint.getConfiguration().getWaitTimeMs();
            } else {
                target = endpoint.getQueue();
            }


            Exchanger exchanger = null;
            while (isRunAllowed() && !shutdownPending) {
                if (concurrent) {
                    // Wait until an exchanger is available, indicating that a
                    // handler thread is ready to handle the next request.
                    // Don't read from kestrel until we know a handler is ready.
                    try {
                        exchanger = exchangerQueue.take();
                    } catch (InterruptedException e) {
                        if (log.isDebugEnabled()) {
                            log.debug("Interrupted, are we stopping? " + (isStopping() || isStopped()));
                        }
                        continue;
                    }


                    // We have the exchanger, so there's a handler thread ready
                    // to handle whatever we may read...so read the next object
                    // from the queue.
                }


                // Poll kestrel until we get an object back
                Object value = null;
                while (isRunAllowed() && !shutdownPending) {
                    if (log.isTraceEnabled()) {
                        log.trace("Polling " + target);
                    }
                    try {
                        value = memcachedClient.get(target);
                        if (value != null) {
                            break;
                        }
                    } catch (Exception e) {
                        if (isRunAllowed() && !shutdownPending) {
                            getExceptionHandler().handleException("Failed to get object from kestrel", e);
                        }
                    }


                    // We didn't get a value back from kestrel
                    if (isRunAllowed() && !shutdownPending) {
                        if (endpoint.getConfiguration().getWaitTimeMs() > 0) {
                            // Kestrel did the blocking for us
                        } else {
                            // We're doing non-blocking get, so in between we
                            // should at least sleep some short period of time
                            // so this loop doesn't go nuts so tightly.
                            try {
                                Thread.sleep(100);
                            } catch (InterruptedException ignored) {
                            }
                        }
                    }
                }


                if (log.isTraceEnabled()) {
                    log.trace("Got object from " + target);
                }


                if (concurrent) {
                    // Pass the object to the handler thread via the exchanger.
                    // The handler will take it from there.
                    try {
                        exchanger.exchange(value);
                    } catch (InterruptedException e) {
                        if (log.isDebugEnabled()) {
                            log.debug("Interrupted, are we stopping? " + (isStopping() || isStopped()));
                        }
                        continue;

View Full Code Here

                target = endpoint.getQueue() + "/t=" + endpoint.getConfiguration().getWaitTimeMs();
            } else {
                target = endpoint.getQueue();
            }


            Exchanger exchanger = null;
            while (isRunAllowed() && !shutdownPending) {
                if (concurrent) {
                    // Wait until an exchanger is available, indicating that a
                    // handler thread is ready to handle the next request.
                    // Don't read from kestrel until we know a handler is ready.
                    try {
                        exchanger = exchangerQueue.take();
                    } catch (InterruptedException e) {
                        if (log.isDebugEnabled()) {
                            log.debug("Interrupted, are we stopping? {}", isStopping() || isStopped());
                        }
                        continue;
                    }


                    // We have the exchanger, so there's a handler thread ready
                    // to handle whatever we may read...so read the next object
                    // from the queue.
                }


                // Poll kestrel until we get an object back
                Object value = null;
                while (isRunAllowed() && !shutdownPending) {
                    log.trace("Polling {}", target);
                    try {
                        value = memcachedClient.get(target);
                        if (value != null) {
                            break;
                        }
                    } catch (Exception e) {
                        if (isRunAllowed() && !shutdownPending) {
                            getExceptionHandler().handleException("Failed to get object from kestrel", e);
                        }
                    }


                    // We didn't get a value back from kestrel
                    if (isRunAllowed() && !shutdownPending) {
                        if (endpoint.getConfiguration().getWaitTimeMs() > 0) {
                            // Kestrel did the blocking for us
                        } else {
                            // We're doing non-blocking get, so in between we
                            // should at least sleep some short period of time
                            // so this loop doesn't go nuts so tightly.
                            try {
                                Thread.sleep(100);
                            } catch (InterruptedException ignored) {
                            }
                        }
                    }
                }


                log.trace("Got object from {}", target);


                if (concurrent) {
                    // Pass the object to the handler thread via the exchanger.
                    // The handler will take it from there.
                    try {
                        exchanger.exchange(value);
                    } catch (InterruptedException e) {
                        if (log.isDebugEnabled()) {
                            log.debug("Interrupted, are we stopping? {}", isStopping() || isStopped());
                        }
                        continue;

View Full Code Here

                target = endpoint.getQueue() + "/t=" + endpoint.getConfiguration().getWaitTimeMs();
            } else {
                target = endpoint.getQueue();
            }


            @SuppressWarnings("rawtypes")
            Exchanger exchanger = null;
            while (isRunAllowed() && !shutdownPending) {
                if (concurrent) {
                    // Wait until an exchanger is available, indicating that a
                    // handler thread is ready to handle the next request.
                    // Don't read from kestrel until we know a handler is ready.
                    try {
                        exchanger = exchangerQueue.take();
                    } catch (InterruptedException e) {
                        if (log.isDebugEnabled()) {
                            log.debug("Interrupted, are we stopping? {}", isStopping() || isStopped());
                        }
                        continue;
                    }


                    // We have the exchanger, so there's a handler thread ready
                    // to handle whatever we may read...so read the next object
                    // from the queue.
                }


                // Poll kestrel until we get an object back
                Object value = null;
                while (isRunAllowed() && !shutdownPending) {
                    log.trace("Polling {}", target);
                    try {
                        value = memcachedClient.get(target);
                        if (value != null) {
                            break;
                        }
                    } catch (Exception e) {
                        if (isRunAllowed() && !shutdownPending) {
                            getExceptionHandler().handleException("Failed to get object from kestrel", e);
                        }
                    }


                    // We didn't get a value back from kestrel
                    if (isRunAllowed() && !shutdownPending) {
                        if (endpoint.getConfiguration().getWaitTimeMs() > 0) {
                            // Kestrel did the blocking for us
                        } else {
                            // We're doing non-blocking get, so in between we
                            // should at least sleep some short period of time
                            // so this loop doesn't go nuts so tightly.
                            try {
                                Thread.sleep(100);
                            } catch (InterruptedException ignored) {
                            }
                        }
                    }
                }


                log.trace("Got object from {}", target);


                if (concurrent) {
                    // Pass the object to the handler thread via the exchanger.
                    // The handler will take it from there.
                    try {
                        exchanger.exchange(value);
                    } catch (InterruptedException e) {
                        if (log.isDebugEnabled()) {
                            log.debug("Interrupted, are we stopping? {}", isStopping() || isStopped());
                        }
                        continue;

View Full Code Here

                target = endpoint.getQueue() + "/t=" + endpoint.getConfiguration().getWaitTimeMs();
            } else {
                target = endpoint.getQueue();
            }


            Exchanger exchanger = null;
            while (isRunAllowed() && !shutdownPending) {
                if (concurrent) {
                    // Wait until an exchanger is available, indicating that a
                    // handler thread is ready to handle the next request.
                    // Don't read from kestrel until we know a handler is ready.
                    try {
                        exchanger = exchangerQueue.take();
                    } catch (InterruptedException e) {
                        if (log.isDebugEnabled()) {
                            log.debug("Interrupted, are we stopping? {}", isStopping() || isStopped());
                        }
                        continue;
                    }


                    // We have the exchanger, so there's a handler thread ready
                    // to handle whatever we may read...so read the next object
                    // from the queue.
                }


                // Poll kestrel until we get an object back
                Object value = null;
                while (isRunAllowed() && !shutdownPending) {
                    log.trace("Polling {}", target);
                    try {
                        value = memcachedClient.get(target);
                        if (value != null) {
                            break;
                        }
                    } catch (Exception e) {
                        if (isRunAllowed() && !shutdownPending) {
                            getExceptionHandler().handleException("Failed to get object from kestrel", e);
                        }
                    }


                    // We didn't get a value back from kestrel
                    if (isRunAllowed() && !shutdownPending) {
                        if (endpoint.getConfiguration().getWaitTimeMs() > 0) {
                            // Kestrel did the blocking for us
                        } else {
                            // We're doing non-blocking get, so in between we
                            // should at least sleep some short period of time
                            // so this loop doesn't go nuts so tightly.
                            try {
                                Thread.sleep(100);
                            } catch (InterruptedException ignored) {
                            }
                        }
                    }
                }


                log.trace("Got object from {}", target);


                if (concurrent) {
                    // Pass the object to the handler thread via the exchanger.
                    // The handler will take it from there.
                    try {
                        exchanger.exchange(value);
                    } catch (InterruptedException e) {
                        if (log.isDebugEnabled()) {
                            log.debug("Interrupted, are we stopping? {}", isStopping() || isStopped());
                        }
                        continue;

View Full Code Here

TOP

Related Classes of java.util.concurrent.Exchanger

org.apache.camel.component.kestrel.KestrelConsumer$Poller

All source code are property of their respective owners. Java is a trademark of Sun Microsystems, Inc and owned by ORACLE Inc. Contact coftware#gmail.com.