/**
    * Logback: the reliable, generic, fast and flexible logging framework.
    * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
    *
    * This program and the accompanying materials are dual-licensed under
    * either the terms of the Eclipse Public License v1.0 as published by
    * the Eclipse Foundation
    *
    *   or (per the licensee's choosing)
   *
   * under the terms of the GNU Lesser General Public License version 2.1
   * as published by the Free Software Foundation.
   */
  package ch.qos.logback.classic.net.mock;
  
  import java.util.concurrent.BlockingQueue;
  import java.util.concurrent.LinkedBlockingQueue;
  import java.util.concurrent.TimeUnit;
  import java.util.concurrent.locks.Condition;
  import java.util.concurrent.locks.Lock;
  import java.util.concurrent.locks.ReentrantLock;
  
  import ch.qos.logback.classic.spi.ILoggingEvent;
  import ch.qos.logback.core.AppenderBase;
  
  /**
   * A mock {@link AppenderBase} with instrumentation for unit testing.
   *
   * @author Carl Harris
   */
  public class MockAppender extends AppenderBase<ILoggingEvent> {
  
      private final Lock lock = new ReentrantLock();
      private final Condition appendCondition = lock.newCondition();
      private final BlockingQueue<ILoggingEvent> events = new LinkedBlockingQueue<ILoggingEvent>();
  
      @Override
      protected void append(ILoggingEvent eventObject) {
          lock.lock();
          try {
              events.offer(eventObject);
              appendCondition.signalAll();
          } finally {
              lock.unlock();
          }
      }
  
      public ILoggingEvent awaitAppend(long delay) throws InterruptedException {
          return events.poll(delay, TimeUnit.MILLISECONDS);
      }
  
      public ILoggingEvent getLastEvent() {
          return events.peek();
      }
  
  }