/*
    * Copyright 2008-2012 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.util.test.io;
  
  import java.io.BufferedInputStream;
  import java.io.File;
  import java.io.FileReader;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.Reader;
  import java.net.URL;
  import java.util.Properties;
  
  import org.apache.commons.io.IOUtils;
  
  /**
   * Utilities to make unit tests with files easier.
   *
   * @author <a href="mailto:robert.reiner@smartics.de">Robert Reiner</a>
   * @version $Revision:591 $
   */
  public final class FileTestUtils
  {
    // ********************************* Fields *********************************
  
    // --- constants ------------------------------------------------------------
  
    // --- members --------------------------------------------------------------
  
    // ****************************** Initializer *******************************
  
    // ****************************** Constructors ******************************
  
    /**
     * Utility class pattern.
     */
    private FileTestUtils()
    {
    }
  
    // ****************************** Inner Classes *****************************
  
    // ********************************* Methods ********************************
  
    // --- init -----------------------------------------------------------------
  
    // --- get&set --------------------------------------------------------------
  
    // --- business -------------------------------------------------------------
  
    /**
     * Returns the specified file from the class path.
     *
     * @param resourceName name of the resource (file or directory) in the class
     *          path.
     * @return the file representation of the resource or <code>null</code> if the
     *         resource does not exist, is not accessible via the
     *         <code>file:/</code> protocol or due to missing privileges.
     */
    public static File getFileFromResource(final String resourceName)
    {
      final ClassLoader classLoader = FileTestUtils.class.getClassLoader(); // NOPMD
      return getFileFromResource(classLoader, resourceName);
    }
  
    /**
     * Returns the specified file from the specified class loader.
     *
     * @param classLoader the class loader to load the resource from.
     * @param resourceName name of the resource (file or directory) in the class
     *          path.
     * @return the file representation of the resource or <code>null</code> if the
     *         resource does not exist, is not accessible via the
     *         <code>file:/</code> protocol or due to missing privileges.
     */
    public static File getFileFromResource(final ClassLoader classLoader,
        final String resourceName)
    {
      final URL url = classLoader.getResource(resourceName);
      final File file = getFileFrom(url);
      return file;
    }
  
    /**
     * Returns the specified file from the class loader associated with the given
     * type.
    *
    * @param type the type to refer to the class loader to load the resource
    *          from. The resource is relative to this type.
    * @param resourceName name of the resource (file or directory) in the class
    *          path.
    * @return the file representation of the resource or <code>null</code> if the
    *         resource does not exist, is not accessible via the
    *         <code>file:/</code> protocol or due to missing privileges.
    */
   public static File getFileFromResource(final Class<?> type,
       final String resourceName)
   {
     return getFileFromResource(type.getClassLoader(), resourceName);
   }
 
   /**
    * Returns the specified file from a resource relative to the given type.
    *
    * @param type the type to refer to the class loader to load the resource
    *          from. The resource is relative to this type.
    * @param relativeResourceName name of the resource (file or directory) in the
    *          class path, relative to the passed in <code>type</code>.
    * @return the file representation of the resource or <code>null</code> if the
    *         resource does not exist, is not accessible via the
    *         <code>file:/</code> protocol or due to missing privileges.
    */
   public static File getFileFromRelativeResource(final Class<?> type,
       final String relativeResourceName)
   {
     final URL url = type.getResource(relativeResourceName);
     final File file = getFileFrom(url);
     return file;
   }
 
   private static File getFileFrom(final URL url)
   {
     if (url != null)
     {
       final String resourceAsString = url.toExternalForm();
 
       if (resourceAsString.startsWith("file:/"))
       {
         final int startIndex = isWindows() ? 6 : 5;
         final String fileName = resourceAsString.substring(startIndex);
         final File file = new File(fileName);
         return file;
       }
     }
     return null;
   }
 
   private static boolean isWindows()
   {
     return File.separatorChar == '\\';
   }
 
   /**
    * Returns a properties object backed by the specified file from a resource
    * relative to the given type with the simple name of the resource with an
    * ending <code>.properties</code> .
    *
    * @param clazz the type to refer to the class loader to load the resource
    *          from. The resource is relative to this type and has its simple
    *          name.
    * @return the properties object containing the properties or empty if the
    *         resource does not exist or is empty.
    */
   public static Properties getPropertiesFromRelativePropertiesFileForClass(
       final Class<?> clazz)
   {
 
     final InputStream is =
         clazz.getResourceAsStream(clazz.getSimpleName().concat(".properties"));
     final BufferedInputStream buffer = new BufferedInputStream(is);
     final Properties props = new Properties();
     try
     {
       props.load(buffer);
     }
     catch (final IOException ioe)
     {
       // Do nohing
     }
     finally
     {
       IOUtils.closeQuietly(buffer);
     }
     return props;
   }
   // --- object basics --------------------------------------------------------
 
 }