Is there a PriorityQueue implementation with fixed capacity and custom comparator?

Question

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Answer 1

Here is one I put together if you have guava. I think it is is pretty complete. Let me know if I missed something.

You can use the gauva ForwardingBlockingQueue so you don't have to map all the other methods.

import com.google.common.util.concurrent.ForwardingBlockingQueue;

public class PriorityBlockingQueueDecorator extends
        ForwardingBlockingQueue {

    public static final class QueueFullException extends IllegalStateException {

        private static final long serialVersionUID = -9218216017510478441L;

    }

    private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;

    private int maxSize;

    private PriorityBlockingQueue delegate;

    public PriorityBlockingQueueDecorator(PriorityBlockingQueue delegate) {
        this(MAX_ARRAY_SIZE, delegate);
    }

    public PriorityBlockingQueueDecorator(int maxSize,
            PriorityBlockingQueue delegate) {
        this.maxSize = maxSize;
        this.delegate = delegate;
    }

    @Override
    protected BlockingQueue delegate() {
        return delegate;
    }

    @Override
    public boolean add(E element) {
        return offer(element);
    }

    @Override
    public boolean addAll(Collection collection) {
        boolean modified = false;
        for (E e : collection)
            if (add(e))
                modified = true;
        return modified;
    }

    @Override
    public boolean offer(E e, long timeout, TimeUnit unit)
            throws InterruptedException {
        return offer(e);
    }

    @Override
    public boolean offer(E o) {
        if (maxSize > size()) {
            throw new QueueFullException();
        }
        return super.offer(o);
    }
}