Android Open Source - AUIL-for-volley Limited Age Memory Cache

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The source code is released under:

Apache License

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Java Source Code

/*******************************************************************************
 * Copyright 2011-2013 Sergey Tarasevich
 *//from  w ww .  j  a va2s.co  m
 * 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.nostra13.universalimageloader.cache.memory.impl;

import com.nostra13.universalimageloader.cache.memory.MemoryCacheAware;

import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

/**
 * Decorator for {@link MemoryCacheAware}. Provides special feature for cache: if some cached object age exceeds defined
 * value then this object will be removed from cache.
 *
 * @author Sergey Tarasevich (nostra13[at]gmail[dot]com)
 * @see MemoryCacheAware
 * @since 1.3.1
 */
public class LimitedAgeMemoryCache<K, V> implements MemoryCacheAware<K, V> {

  private final MemoryCacheAware<K, V> cache;

  private final long maxAge;
  private final Map<K, Long> loadingDates = Collections.synchronizedMap(new HashMap<K, Long>());

  /**
   * @param cache  Wrapped memory cache
   * @param maxAge Max object age <b>(in seconds)</b>. If object age will exceed this value then it'll be removed from
   *               cache on next treatment (and therefore be reloaded).
   */
  public LimitedAgeMemoryCache(MemoryCacheAware<K, V> cache, long maxAge) {
    this.cache = cache;
    this.maxAge = maxAge * 1000; // to milliseconds
  }

  @Override
  public boolean put(K key, V value) {
    boolean putSuccesfully = cache.put(key, value);
    if (putSuccesfully) {
      loadingDates.put(key, System.currentTimeMillis());
    }
    return putSuccesfully;
  }

  @Override
  public V get(K key) {
    Long loadingDate = loadingDates.get(key);
    if (loadingDate != null && System.currentTimeMillis() - loadingDate > maxAge) {
      cache.remove(key);
      loadingDates.remove(key);
    }

    return cache.get(key);
  }

  @Override
  public void remove(K key) {
    cache.remove(key);
    loadingDates.remove(key);
  }

  @Override
  public Collection<K> keys() {
    return cache.keys();
  }

  @Override
  public void clear() {
    cache.clear();
    loadingDates.clear();
  }
}

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