/**

  * Copyright 2010 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.osedu.org/licenses/ECL-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 org.kuali.student.common.util;

 import java.io.File;

 import java.io.FileInputStream;

 import java.io.FileNotFoundException;

 import java.io.IOException;

 import java.io.InputStream;

 import java.net.URL;

 import java.util.HashMap;

 import java.util.Map;

 import java.util.Properties;

 /**

  * A really freaking simple properties filter that returns a properties map for a subset of a properties file. Give this

  * method the file name of the properties file, and then give it the prefix to filter on. The prefix gets a "." appended to

  * it on filtering.

  * <p>

  * For example, if the properties are:

  * <ul>

  * <li>prop1.test1.value1</li>

  * <li>prop1.test2.value2</li>

  * <li>prop2.test1.value1</li>

  * <li>prop1butnottherealprop1.test3.value3</li>

  * </ul>

  * Then filtering on "prop1" returns a map with values:

  * <ul>

  * <li>test1.value1</li>

  * <li>test2.value2</li>

  * </ul>

  * </p>

  * 

  * @author Kuali Student Team (ks.team2@kuali.org)

  */

 public class PropertiesFactory {

     Properties properties = new Properties();

     /**

      * This constructs a PropertiesFactory.

      * 

      * @param filename

      *            the filename of the properties file as determined by {@link ClassLoader#getSystemResource(String)}.

      * @throws IOException

      */

     public PropertiesFactory(String filename) throws IOException {

         this(ClassLoader.getSystemResource(filename).openStream());

     }

     /**

      * This constructs a PropertiesFactory.

      * 

      * @param file

      *            the properties file

      * @throws FileNotFoundException

      * @throws IOException

      */

     public PropertiesFactory(File file) throws FileNotFoundException, IOException {

         this(new FileInputStream(file));

     }

     /**

      * This constructs a PropertiesFactory.

      * 

      * @param in

      *            an InputStream to read the properties from

      * @throws IOException

      */

     public PropertiesFactory(InputStream in) throws IOException {

         try {

             properties.load(in);

         } finally {

             if (in != null) {

                 try {

                     in.close();

                 } catch (IOException e) {}

             }

         }

     }

     /**

      * This method filters the properties based on the prefix given as described above. The prefix will be appended with a

      * "." delimiter and the returned values will not have either the prefix or the delimiter.

      * 

      * @param prefix

      *            the prefix to filter on

      * @return a map of the properties minus their prefix. This list is really String,Object, oh well.

      */

     public Map<Object, Object> getProperties(String prefix) {

         Map<Object, Object> map = new HashMap<Object, Object>();

         for (Object key : properties.keySet()) {

             String realPrefix = prefix + ".";

             String keyString = key.toString();

             if (keyString.startsWith(realPrefix)) {

                 map.put(keyString.substring(realPrefix.length()), properties.get(key));

             }

         }

         return map;

     }

     /**

      * A static version of the properties filter. <code><pre>

      *     <bean id="test" class="org.kuali.student.common.util.PropertiesFactory" factory-method="getProperties" >

      *         <constructor-arg value="file.properties"/>

      *         <constructor-arg value="prefix1"/>

      *     </bean>

      * </pre></code>

      * 

      * @param filename

      * @param prefix

      *            the prefix to filter on

      * @return a map of the properties minus their prefix. This list is really String,Object, oh well.

      * @throws IOException

      */

     public static Map<Object, Object> getProperties(String filename, String prefix) throws IOException {

         Properties props = new Properties();

         InputStream in = null;

         URL propFile = ClassLoader.getSystemResource(filename);

         // System.out.println("\t===PROPFACT: "+propFile);

         try {

             props.load(in = propFile.openStream());

         } finally {

             if (in != null) {

                 try {

                     in.close();

                 } catch (IOException e) {}

             }

         }

         Map<Object, Object> map = new HashMap<Object, Object>();

         for (Object key : props.keySet()) {

             String realPrefix = prefix + ".";

             String keyString = key.toString();

             if (keyString.startsWith(realPrefix)) {

                 map.put(keyString.substring(realPrefix.length()), props.get(key));

             }

         }

         return map;

     }

 }