Class LinkedBlockingQueue

classpath/java/util/concurrent/LinkedBlockingQueue.java:18–302

import java.util.LinkedList;

public class LinkedBlockingQueue<T> extends AbstractQueue<T> 
                                    implements BlockingQueue<T> {
  private final Object collectionLock;
  private final LinkedList<T> storage;
  private final int capacity;
  
  public LinkedBlockingQueue() {
    this(Integer.MAX_VALUE);
  }
  
  public LinkedBlockingQueue(int capacity) {
    collectionLock = new Object();
    this.capacity = capacity;
    storage = new LinkedList<T>();
  }
  
  // should be synchronized on collectionLock before calling
  private void handleRemove() {
    collectionLock.notifyAll();
  }
  
  // should be synchronized on collectionLock before calling
  private void handleAdd() {
    collectionLock.notifyAll();
  }

  // should be synchronized on collectionLock before calling
  private void blockTillNotFull() throws InterruptedException {
    blockTillNotFull(Long.MAX_VALUE);
  }

  // should be synchronized on collectionLock before calling
  private void blockTillNotFull(long maxWaitInMillis) throws InterruptedException {
    if (capacity > storage.size()) {
      return;
    }
    
    long startTime = 0;
    if (maxWaitInMillis != Long.MAX_VALUE) {
      startTime = System.currentTimeMillis();
    }
    long remainingWait = maxWaitInMillis;
    while (remainingWait > 0) {
      collectionLock.wait(remainingWait);
      
      if (capacity > storage.size()) {
        return;
      } else if (maxWaitInMillis != Long.MAX_VALUE) {
        remainingWait = maxWaitInMillis - (System.currentTimeMillis() - startTime);
      }
    }
  }

  // should be synchronized on collectionLock before calling
  private void blockTillNotEmpty() throws InterruptedException {
    blockTillNotEmpty(Long.MAX_VALUE);
  }