com.kenlin.awsec2offering.Cache.java Source code

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Here is the source code for com.kenlin.awsec2offering.Cache.java

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/*
 * Copyright 2014 Ken K. Lin. 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.kenlin.awsec2offering;

import java.util.concurrent.ConcurrentHashMap;

import com.fasterxml.jackson.databind.node.ArrayNode;

public class Cache {
    private static final long MILLIS_IN_DAY = 1000 * 60 * 60 * 24;

    private ConcurrentHashMap<String, ArrayNode> cache = null;
    private long oldest = 0;
    private long ttl = MILLIS_IN_DAY;

    public Cache() {
        cache = new ConcurrentHashMap<String, ArrayNode>();
    }

    public ArrayNode get(String key) {
        if (System.currentTimeMillis() > (oldest + ttl)) {
            cache.clear();
            oldest = 0;
            return null;
        } else {
            ArrayNode offerings = cache.get(key);
            return offerings;
        }
    }

    public ArrayNode put(String key, ArrayNode offerings) {
        if (oldest == 0)
            oldest = System.currentTimeMillis();
        return cache.put(key, offerings);
    }
}