cloudstack/console-proxy/src/com/cloud/consoleproxy/AjaxFIFOImageCache.java
2012-06-12 09:38:19 -04:00

81 lines
2.3 KiB
Java

// 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 {
private static final Logger s_logger = Logger.getLogger(AjaxFIFOImageCache.class);
private List<Integer> fifoQueue;
private Map<Integer, byte[]> cache;
private int cacheSize;
private int nextKey = 1;
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(s_logger.isTraceEnabled())
s_logger.trace("Remove image from cache, key: " + keyToRemove);
}
int key = getNextKey();
if(s_logger.isTraceEnabled())
s_logger.trace("Add image to cache, key: " + key);
cache.put(key, image);
fifoQueue.add(key);
return key;
}
public synchronized byte[] getImage(int key) {
if(cache.containsKey(key)) {
if(s_logger.isTraceEnabled())
s_logger.trace("Retrieve image from cache, key: " + key);
return cache.get(key);
}
if(s_logger.isTraceEnabled())
s_logger.trace("Image is no long in cache, key: " + key);
return null;
}
public synchronized int getNextKey() {
return nextKey++;
}
}