/*

  * Copyright 2012-2013 smartics, Kronseder & Reiner GmbH

  *

  * 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 de.smartics.properties.spi.config.support;

 import java.io.BufferedInputStream;

 import java.io.IOException;

 import java.io.InputStream;

 import java.util.Properties;

 import org.apache.commons.io.IOUtils;

 import de.smartics.properties.api.config.domain.ConfigurationLoadingException;

 import de.smartics.properties.api.config.domain.key.ConfigurationKey;

 /**

  * Simple utilities class to help on dealing with properties.

  */

 public final class PropertiesHelper

 {

   // ********************************* Fields *********************************

   // --- constants ------------------------------------------------------------

   // --- members --------------------------------------------------------------

   /**

    * The key to the configuration to load properties for.

    */

   private final ConfigurationKey<?> key;

   // ****************************** Initializer *******************************

   // ****************************** Constructors ******************************

   /**

    * Default constructor.

    *

    * @param key the key to the configuration to load properties for.

    */

   public PropertiesHelper(final ConfigurationKey<?> key)

   {

     this.key = key;

   }

   // ****************************** Inner Classes *****************************

   // ********************************* Methods ********************************

   // --- init -----------------------------------------------------------------

   // --- get&set --------------------------------------------------------------

   // --- business -------------------------------------------------------------

   /**

    * Reads the properties from the thread context class path location.

    *

    * @param resourceId the resource on the class path to read.

    * @return the properties from the class path.

    */

   public Properties readProperties(final String resourceId)

   {

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

     return readProperties(loader, resourceId);

   }

   /**

    * Reads the properties from the given class path location.

    *

    * @param classLoader the class loader to access the resource.

    * @param resourceId the resource on the class path to read.

    * @return the properties from the class path.

    */

   public Properties readProperties(final ClassLoader classLoader,

       final String resourceId)

   {

     final InputStream input = classLoader.getResourceAsStream(resourceId);

     return readProperties(resourceId, input);

   }

   /**

    * Reads the properties from the given stream.

    * <p>

    * Closes the stream after the properties are read.

    * </p>

    *

    * @param resourceId the identifier of the stream. Used for error reporting.

    * @param input the stream to read from.

    * @return the properties from the stream.

    */

   public Properties readProperties(final String resourceId,

       final InputStream input)

   {

     final BufferedInputStream bin = new BufferedInputStream(input);

     try

     {

       final Properties properties = new Properties();

       properties.load(bin);

       return properties;

     }

     catch (final IOException e)

     {

       throw new ConfigurationLoadingException(e, key, resourceId);

     }

     finally

     {

       IOUtils.closeQuietly(bin);

     }

   }

   // --- object basics --------------------------------------------------------

 }