Java tutorial
/* * 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.batchee.cli.command; import io.airlift.command.Option; import org.apache.batchee.container.exception.BatchContainerRuntimeException; import org.apache.commons.io.IOUtils; import java.io.IOException; import java.io.OutputStream; import java.net.Socket; import java.util.concurrent.CountDownLatch; import java.util.concurrent.TimeUnit; import java.util.concurrent.atomic.AtomicReference; public abstract class SocketCommand extends SocketConfigurableCommand { @Option(name = "-timeout", description = "timeout for socket case") private int timeout = 60000; protected boolean shouldUseSocket() { return baseUrl == null; } protected abstract String command(); protected abstract void defaultRun(); protected void sendCommand() { if (adminSocket < 0) { throw new BatchContainerRuntimeException("specify -socket to be able to run this command"); } Socket socket = null; try { socket = new Socket("localhost", adminSocket); socket.setSoTimeout(timeout); final CountDownLatch latch = new CountDownLatch(1); final AtomicReference<Integer> answer = new AtomicReference<Integer>(); new AnswerThread(socket, answer, latch).start(); final OutputStream outputStream = socket.getOutputStream(); outputStream.write(command().getBytes()); outputStream.flush(); socket.shutdownOutput(); try { latch.await(timeout, TimeUnit.MILLISECONDS); } catch (InterruptedException e) { info("no answer after " + timeout + "ms"); return; } if (answer.get() != 0) { info("unexpected answer: " + answer.get()); } } catch (final IOException e) { throw new BatchContainerRuntimeException(e); } finally { IOUtils.closeQuietly(socket); } } @Override public void doRun() { if (shouldUseSocket()) { sendCommand(); } else { defaultRun(); } postCommand(); } protected abstract void postCommand(); private static class AnswerThread extends Thread { private final Socket socket; private final AtomicReference<Integer> answer; private final CountDownLatch latch; public AnswerThread(final Socket socket, final AtomicReference<Integer> answer, final CountDownLatch latch) { this.socket = socket; this.answer = answer; this.latch = latch; setName("batchee-answer-thread"); } @Override public void run() { try { answer.set(socket.getInputStream().read()); } catch (IOException e) { answer.set(-1); } latch.countDown(); } } }