/*

  * Copyright 2005-2007 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.rice.kns.util.properties;

 import java.io.IOException;

 import java.io.InputStream;

 import java.net.URL;

 import java.util.Properties;

 import org.apache.commons.lang.StringUtils;

 import org.apache.commons.logging.Log;

 import org.apache.commons.logging.LogFactory;

 import org.kuali.rice.kns.exception.PropertiesException;

 /**

  * This class is used to obtain properties from a properites file.

  * 

  * 

  */

 public class FilePropertySource implements PropertySource {

     private static Log log = LogFactory.getLog(FilePropertySource.class);

     private String fileName;

     private boolean allowOverrides;

     /**

      * Set source fileName.

      * 

      * @param fileName

      */

     public void setFileName(String fileName) {

         this.fileName = fileName;

     }

     /**

      * @return source fileName

      */

     public String getFileName() {

         return this.fileName;

     }

     public boolean isAllowOverrides() {

         return this.allowOverrides;

     }

     public void setAllowOverrides(boolean allowOverrides) {

         this.allowOverrides = allowOverrides;

     }

     /**

      * Attempts to load properties from a properties file which has the current fileName and is located on the classpath.

      * 

      * @see org.kuali.rice.kns.util.properties.PropertySource#loadProperties()

      * @throws IllegalStateException if the fileName is null or empty

      */

     public Properties loadProperties() {

         if (StringUtils.isBlank(getFileName())) {

             throw new IllegalStateException("invalid (blank) fileName");

         }

         Properties properties = new Properties();

         ClassLoader loader = Thread.currentThread().getContextClassLoader();

         URL url = loader.getResource(getFileName());

         if (url == null) {

             throw new PropertiesException("unable to locate properties file '" + getFileName() + "'");

         }

         InputStream in = null;

         try {

             in = url.openStream();

             properties.load(in);

         }

         catch (IOException e) {

             throw new PropertiesException("error loading from properties file '" + getFileName() + "'", e);

         }

         finally {

             if (in != null) {

                 try {

                     in.close();

                 }

                 catch (IOException e) {

                     log.error("caught exception closing InputStream: " + e);

                 }

             }

         }

         return properties;

     }

 }