/*
* Copyright (c) 2008-2012, Hazel Bilisim Ltd. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.hazelcast.util;
import java.util.AbstractQueue;
import java.util.Iterator;
/**
* Not Thread-Safe
*
* @param <E>
*/
public final class SimpleBoundedQueue<E> extends AbstractQueue<E> {
final int maxSize;
final E[] objects;
int add = 0;
int remove = 0;
int size = 0;
public SimpleBoundedQueue(int maxSize) {
this.maxSize = maxSize;
objects = (E[]) new Object[maxSize];
}
@Override
public boolean add(E obj) {
if (size == maxSize) {
return false;
}
objects[add] = obj;
add++;
size++;
if (add == maxSize) {
add = 0;
}
return true;
}
public E pop() {
if (size == 0)
return null;
int last = add - 1;
E value = objects[last];
objects[last] = null;
size--;
add--;
return value;
}
@Override
public int size() {
return size;
}
public int remainingCapacity() {
return maxSize - size;
}
public boolean offer(E o) {
return add(o);
}
public E peek() {
if (size == 0)
return null;
return objects[remove];
}
public E poll() {
if (size == 0)
return null;
E value = objects[remove];
objects[remove] = null;
remove++;
size--;
if (remove == maxSize) {
remove = 0;
}
return value;
}
@Override
public void clear() {
for (int i = 0; i < maxSize; i++) {
objects[0] = null;
}
add = 0;
remove = 0;
size = 0;
}
@Override
public Iterator<E> iterator() {
throw new UnsupportedOperationException();
}
}