| /** |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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.camel.util; |
| |
| import java.util.concurrent.Callable; |
| import java.util.concurrent.CountDownLatch; |
| import java.util.concurrent.ExecutorService; |
| import java.util.concurrent.Future; |
| |
| import org.apache.camel.AsyncCallback; |
| import org.apache.camel.AsyncProcessor; |
| import org.apache.camel.Exchange; |
| import org.apache.camel.Processor; |
| import org.apache.camel.spi.UnitOfWork; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /** |
| * Helper methods for {@link AsyncProcessor} objects. |
| */ |
| public final class AsyncProcessorHelper { |
| |
| private static final transient Logger LOG = LoggerFactory.getLogger(AsyncProcessorHelper.class); |
| |
| private AsyncProcessorHelper() { |
| // utility class |
| } |
| |
| /** |
| * Calls the async version of the processor's process method. |
| * <p/> |
| * This implementation supports transacted {@link Exchange}s which ensure those are run in a synchronous fashion. |
| * See more details at {@link org.apache.camel.AsyncProcessor}. |
| * |
| * @param processor the processor |
| * @param exchange the exchange |
| * @param callback the callback |
| * @return <tt>true</tt> to continue execute synchronously, <tt>false</tt> to continue being executed asynchronously |
| */ |
| public static boolean process(final AsyncProcessor processor, final Exchange exchange, final AsyncCallback callback) { |
| boolean sync; |
| |
| if (exchange.isTransacted()) { |
| // must be synchronized for transacted exchanges |
| LOG.trace("Transacted Exchange must be routed synchronously for exchangeId: {} -> {}", exchange.getExchangeId(), exchange); |
| try { |
| process(processor, exchange); |
| } catch (Throwable e) { |
| exchange.setException(e); |
| } |
| callback.done(true); |
| sync = true; |
| } else { |
| final UnitOfWork uow = exchange.getUnitOfWork(); |
| |
| // allow unit of work to wrap callback in case it need to do some special work |
| // for example the MDCUnitOfWork |
| AsyncCallback async = callback; |
| if (uow != null) { |
| async = uow.beforeProcess(processor, exchange, callback); |
| } |
| |
| // we support asynchronous routing so invoke it |
| sync = processor.process(exchange, async); |
| |
| // execute any after processor work (in current thread, not in the callback) |
| if (uow != null) { |
| uow.afterProcess(processor, exchange, callback, sync); |
| } |
| } |
| |
| if (LOG.isTraceEnabled()) { |
| LOG.trace("Exchange processed and is continued routed {} for exchangeId: {} -> {}", |
| new Object[]{sync ? "synchronously" : "asynchronously", exchange.getExchangeId(), exchange}); |
| } |
| return sync; |
| } |
| |
| /** |
| * Calls the async version of the processor's process method and waits |
| * for it to complete before returning. This can be used by {@link AsyncProcessor} |
| * objects to implement their sync version of the process method. |
| * |
| * @param processor the processor |
| * @param exchange the exchange |
| * @throws Exception can be thrown if waiting is interrupted |
| */ |
| public static void process(final AsyncProcessor processor, final Exchange exchange) throws Exception { |
| final CountDownLatch latch = new CountDownLatch(1); |
| boolean sync = processor.process(exchange, new AsyncCallback() { |
| public void done(boolean doneSync) { |
| if (!doneSync) { |
| LOG.trace("Asynchronous callback received for exchangeId: {}", exchange.getExchangeId()); |
| latch.countDown(); |
| } |
| } |
| |
| @Override |
| public String toString() { |
| return "Done " + processor; |
| } |
| }); |
| if (!sync) { |
| LOG.trace("Waiting for asynchronous callback before continuing for exchangeId: {} -> {}", |
| exchange.getExchangeId(), exchange); |
| latch.await(); |
| LOG.trace("Asynchronous callback received, will continue routing exchangeId: {} -> {}", |
| exchange.getExchangeId(), exchange); |
| } |
| } |
| |
| } |