/**
    * Copyright 2010-2013 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.spring;
  
  import java.util.Properties;
  
  import org.kuali.common.util.Assert;
  import org.kuali.common.util.LocationUtils;
  import org.kuali.common.util.ModeUtils;
  import org.kuali.common.util.PropertyUtils;
  import org.kuali.common.util.property.PropertiesContext;
  import org.springframework.beans.factory.FactoryBean;
  
  /**
   * The improvement over Springs <code>PropertiesFactoryBean</code> is the ability to dynamically resolve placeholders in the property locations themselves.
   */
  public class PropertiesLoaderFactoryBean extends PropertiesContext implements FactoryBean<Properties> {
  
  	protected Properties global = PropertyUtils.getGlobalProperties();
  	boolean singleton = true;
  
  	@Override
  	public Properties getObject() throws Exception {
  		Assert.notNull(helper, "helper is null");
  		Assert.notNull(locations, "locations are null");
  		Assert.notNull(encoding, "encoding is null");
  		Assert.notNull(missingLocationsMode, "missingLocationsMode is null");
  		Properties global = PropertyUtils.getGlobalProperties();
  		this.properties = PropertyUtils.toEmpty(properties);
  		Properties result = new Properties();
  		for (String location : locations) {
  			Properties resolverProperties = PropertyUtils.combine(properties, result, global);
  			String resolvedLocation = helper.replacePlaceholders(location, resolverProperties);
  			if (LocationUtils.exists(resolvedLocation)) {
  				Properties properties = PropertyUtils.load(location, encoding);
  				result.putAll(properties);
  			} else {
  				ModeUtils.validate(missingLocationsMode, "Skipping non-existent location [" + resolvedLocation + "]");
  			}
  		}
  		return result;
  	}
  
  	@Override
  	public Class<Properties> getObjectType() {
  		return Properties.class;
  	}
  
  	@Override
  	public boolean isSingleton() {
  		return singleton;
  	}
  
  	public void setSingleton(boolean singleton) {
  		this.singleton = singleton;
  	}
  }