package org.apache.maven.plugins.checkstyle.rss;
   
   /*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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.
   */
  
  import org.apache.maven.plugin.MojoExecutionException;
  import org.apache.maven.plugin.logging.Log;
  import org.apache.maven.plugin.logging.SystemStreamLog;
  import org.apache.velocity.context.Context;
  import org.apache.velocity.exception.ResourceNotFoundException;
  import org.apache.velocity.exception.VelocityException;
  import org.codehaus.plexus.velocity.VelocityComponent;
  
  import java.io.File;
  import java.io.FileWriter;
  import java.io.IOException;
  import java.io.Writer;
  
  /**
   * <p>
   * A component to work with VelocityTemplates from within plugins.
   * <p>
   * You will need to reference the velocity component as a parameter
   * in your plugin.  Like this:
   * <pre>
   * /&#042;&#042;
   *  &#042; Velocity Component
   *  &#042; &#064;component
   *  &#042;/
   *  private VelocityComponent velocity;
   * </pre>
   *
   * @author <a href="mailto:joakim@erdfelt.net">Joakim Erdfelt</a>
   *
   */
  public class VelocityTemplate
  {
      private String templateDirectory;
  
      private Log log;
  
      private VelocityComponent velocity;
  
      public VelocityTemplate( VelocityComponent velocityComponent, String templateBaseDirectory )
      {
          this.velocity = velocityComponent;
          this.templateDirectory = templateBaseDirectory;
      }
  
      public String getTemplateDirectory()
      {
          return templateDirectory;
      }
  
      public VelocityComponent getVelocity()
      {
          return velocity;
      }
  
      /**
       * Using a specified Velocity Template and provided context, create the outputFilename.
       *
       * @param outputFilename the file to be generated.
       * @param template       the velocity template to use.
       * @param context        the velocity context map.
       * @throws VelocityException if the template was not found or any other Velocity exception.
       * @throws MojoExecutionException if merging the velocity template failed.
       * @throws IOException if there was an error when writing to the output file.
       */
      public void generate( String outputFilename, String template, Context context )
          throws VelocityException, MojoExecutionException, IOException
      {
          Writer writer = null;
  
          try
          {
              File f = new File( outputFilename );
  
              if ( !f.getParentFile().exists() )
              {
                  f.getParentFile().mkdirs();
              }
  
             writer = new FileWriter( f );
 
             getVelocity().getEngine().mergeTemplate( templateDirectory + "/" + template, context, writer );
         }
         catch ( ResourceNotFoundException e )
         {
             throw new ResourceNotFoundException( "Template not found: " + templateDirectory + "/" + template, e );
         }
         catch ( VelocityException | IOException e )
         {
             throw e; // to get past generic catch for Exception.
         }
         catch ( Exception e )
         {
             throw new MojoExecutionException( e.getMessage(), e );
         }
         finally
         {
             if ( writer != null )
             {
                 writer.flush();
                 writer.close();
 
                 getLog().debug( "File " + outputFilename + " created..." );
             }
         }
     }
 
     public void setTemplateDirectory( String templateDirectory )
     {
         this.templateDirectory = templateDirectory;
     }
 
     public void setVelocity( VelocityComponent velocity )
     {
         this.velocity = velocity;
     }
 
     public Log getLog()
     {
         if ( this.log == null )
         {
             this.log = new SystemStreamLog();
         }
         return log;
     }
 
     public void setLog( Log log )
     {
         this.log = log;
     }
 
 }