| // Licensed to the Apache Software Foundation (ASF) under one |
| // or more contributor license agreements. See the NOTICE file |
| // distributed with this work for additional information |
| // regarding copyright ownership. The ASF licenses this file |
| // to you 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.cloud.consoleproxy; |
| |
| import java.util.ArrayList; |
| import java.util.HashMap; |
| import java.util.List; |
| import java.util.Map; |
| |
| import com.cloud.consoleproxy.util.Logger; |
| |
| public class AjaxFIFOImageCache { |
| protected Logger logger = Logger.getLogger(getClass()); |
| |
| private List<Integer> fifoQueue; |
| private Map<Integer, byte[]> cache; |
| private int cacheSize; |
| private int nextKey = 0; |
| |
| public AjaxFIFOImageCache(int cacheSize) { |
| this.cacheSize = cacheSize; |
| fifoQueue = new ArrayList<Integer>(); |
| cache = new HashMap<Integer, byte[]>(); |
| } |
| |
| public synchronized void clear() { |
| fifoQueue.clear(); |
| cache.clear(); |
| } |
| |
| public synchronized int putImage(byte[] image) { |
| while (cache.size() >= cacheSize) { |
| Integer keyToRemove = fifoQueue.remove(0); |
| cache.remove(keyToRemove); |
| |
| if (logger.isTraceEnabled()) |
| logger.trace("Remove image from cache, key: " + keyToRemove); |
| } |
| |
| int key = getNextKey(); |
| |
| if (logger.isTraceEnabled()) |
| logger.trace("Add image to cache, key: " + key); |
| |
| cache.put(key, image); |
| fifoQueue.add(key); |
| return key; |
| } |
| |
| public synchronized byte[] getImage(int key) { |
| if (key == 0) { |
| key = nextKey; |
| } |
| if (cache.containsKey(key)) { |
| if (logger.isTraceEnabled()) |
| logger.trace("Retrieve image from cache, key: " + key); |
| |
| return cache.get(key); |
| } |
| |
| if (logger.isTraceEnabled()) |
| logger.trace("Image is no long in cache, key: " + key); |
| return null; |
| } |
| |
| public synchronized int getNextKey() { |
| return ++nextKey; |
| } |
| } |