Class AbstractQueue

classpath/java/util/AbstractQueue.java:13–67

package java.util;

public abstract class AbstractQueue<T> extends AbstractCollection<T> implements Queue<T> {
  
  protected AbstractQueue() {
    super();
  }
  
  @Override
  public boolean add(T element) {
    if (offer(element)) {
      return true;
    } else {
      throw new IllegalStateException();
    }
  }

  @Override
  public boolean addAll(Collection <? extends T> collection) {
    if (collection == null) {
      throw new NullPointerException();
    }

    for (T element : collection) {
      add(element);
    }

    return true;
  }

  @Override
  public void clear() {
    while (size() > 0) {
      poll();
    }
  }

  @Override
  public T element() {
    T result = peek();
    if (result == null) {
      throw new NoSuchElementException();
    } else {
      return result;
    }
  }

  @Override
  public T remove() {
    T result = poll();
    if (result == null) {
      throw new NoSuchElementException();
    } else {
      return result;
    }
  }
}