scouter.util.RequestQueue Maven / Gradle / Ivy
/*
* Copyright 2015 the original author or authors.
* @https://github.com/scouter-project/scouter
*
* 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.
*
* The initial code from "Guarded Suspension", Java 언어로 배우는 디자인 패턴 입문 - 멀티 쓰레드 편 저자 Yuki Hiroshi
*/
package scouter.util;
public class RequestQueue {
private java.util.LinkedList queue;
private int capacity;
public RequestQueue(int capacity) {
this.capacity = capacity;
this.queue = new java.util.LinkedList();
}
public synchronized V get() {
while (queue.size() <= 0) {
try {
wait();
} catch (InterruptedException e) {
}
}
return queue.removeFirst();
}
public synchronized V getNoWait() {
if (queue.size() > 0) {
return queue.removeFirst();
} else {
return null;
}
}
public synchronized V get(long timeout) {
if (queue.size() > 0) {
return queue.removeFirst();
}
long timeTo = System.currentTimeMillis() + timeout;
long time = timeout;
while (queue.isEmpty()) {
try {
if (time > 0)
wait(time);
} catch (InterruptedException e) {
}
time = timeTo - System.currentTimeMillis();
if (time <= 0) {
break;
}
}
if (queue.size() > 0) {
return queue.removeFirst();
}
return null;
}
public synchronized boolean putForce(V o) {
if (capacity <= 0 || queue.size() < capacity) {
queue.add(o);
notifyAll();
return true;
} else {
while (queue.size() >= capacity) {
queue.removeFirst();
}
queue.add(o);
notifyAll();
return false;
}
}
public synchronized boolean put(V o) {
if (capacity <= 0 || queue.size() < capacity) {
queue.add(o);
notifyAll();
return true;
} else {
notify();
return false;
}
}
public synchronized boolean putNotifySingle(V o) {
if (capacity <= 0 || queue.size() < capacity) {
queue.add(o);
notify();
return true;
} else {
notify();
return false;
}
}
public synchronized void clear() {
queue.clear();
}
public int size() {
return queue.size();
}
public int getCapacity() {
return this.capacity;
}
public void setCapacity(int size) {
this.capacity = size;
}
}