/**
    * 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.core.issue;
  
  import java.util.concurrent.locks.Lock;
  import java.util.concurrent.locks.ReentrantLock;
  
  import ch.qos.logback.core.contention.RunnableWithCounterAndDone;
  
  /**
   * A runnable which behaves differently depending on the desired locking model.
   * 
   * @author Joern Huxhorn
   * @author Ceki Gulcu
   */
  public class SelectiveLockRunnable extends RunnableWithCounterAndDone {
  
      enum LockingModel {
          NOLOCK, SYNC, FAIR, UNFAIR;
      }
  
      static Object LOCK = new Object();
      static Lock FAIR_LOCK = new ReentrantLock(true);
      static Lock UNFAIR_LOCK = new ReentrantLock(false);
  
      LockingModel model;
  
      SelectiveLockRunnable(LockingModel model) {
          this.model = model;
      }
  
      public void run() {
          switch (model) {
          case NOLOCK:
              nolockRun();
              break;
          case SYNC:
              synchronizedRun();
              break;
          case FAIR:
              fairLockRun();
              break;
          case UNFAIR:
              unfairLockRun();
              break;
          }
      }
  
      void fairLockRun() {
          for (;;) {
              FAIR_LOCK.lock();
              counter++;
              FAIR_LOCK.unlock();
              if (done) {
                  return;
              }
          }
      }
  
      void unfairLockRun() {
          for (;;) {
              UNFAIR_LOCK.lock();
              counter++;
              UNFAIR_LOCK.unlock();
              if (done) {
                  return;
              }
          }
      }
  
      void nolockRun() {
          for (;;) {
              counter++;
              if (done) {
                  return;
              }
          }
      }
  
      void synchronizedRun() {
          for (;;) {
              synchronized (LOCK) {
                  counter++;
              }
              if (done) {
                  return;
              }
          }
     }
 
     @Override
     public String toString() {
         return "SelectiveLockRunnable " + model;
     }
 }