/**
    * Copyright 2010-2014 The Kuali Foundation
    *
    * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php
    *
   * 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 org.kuali.common.util.properties;
  
  import java.util.Properties;
  
  import org.kuali.common.util.Assert;
  import org.kuali.common.util.cache.Cache;
  import org.kuali.common.util.property.ImmutableProperties;
  
  public final class CachingLoader implements PropertiesLoader {
  
  	private final Cache<String, Properties> cache;
  	private final LocationLoader loader;
  
  	public CachingLoader(Location location, Cache<String, Properties> cache) {
  		this(location, location.getValue(), cache);
  	}
  
  	public CachingLoader(Location location, String value, Cache<String, Properties> cache) {
  		Assert.noNulls(cache);
  		this.cache = cache;
  		this.loader = new LocationLoader(location, value);
  	}
  
  	@Override
  	public Properties load() {
  
  		if (!loader.getLocation().isCacheable()) {
  			return loader.load();
  		}
  
  		Properties properties = cache.get(loader.getValue());
  		if (properties == null) {
  			properties = new ImmutableProperties(loader.load());
  			this.cache.put(loader.getValue(), properties);
  		}
  		return properties;
  
  	}
  
  }