cloudstack/console-proxy/src/com/cloud/consoleproxy/AjaxFIFOImageCache.java

83 lines
2.3 KiB
Java

/**
* Copyright (C) 2010 Cloud.com, Inc. All rights reserved.
*
* This software is licensed under the GNU General Public License v3 or later.
*
* It is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
package com.cloud.consoleproxy;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import com.cloud.console.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++;
}
}