package org.apache.maven.plugins.scm.release;
   
   /* ====================================================================
    *   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 java.io.File;
  import java.io.FileOutputStream;
  import java.io.OutputStream;
  import java.io.PrintStream;
  import java.util.ArrayList;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  
  import org.apache.commons.io.FileUtils;
  import org.dom4j.Document;
  import org.dom4j.Namespace;
  import org.dom4j.Node;
  import org.dom4j.io.OutputFormat;
  import org.dom4j.io.SAXReader;
  import org.dom4j.io.XMLWriter;
  import org.jaxen.XPath;
  import org.jaxen.dom4j.Dom4jXPath;
  import org.xml.sax.Attributes;
  import org.xml.sax.SAXException;
  import org.xml.sax.helpers.XMLFilterImpl;
  
  /**
   * This is the base class for any tool that attempts to transform fields
   * in the POM. Currently we are using the XML form of the POM and using Jaxen
   * but eventually we will be able to perform the same transformations on
   * POM beans. Jaxen needs to be modified and some serious cleanup needs to
   * go on in Maven internally, but this will serve as a start. An attempt is
   * made to make this tool GUI friendly.
   *
   * @author <a href="mailto:jason@zenplex.com">Jason van Zyl</a>
   *
   * @version $Id: AbstractPomTransformer.java 521198 2007-03-22 10:39:43Z ltheussl $
   */
  public abstract class AbstractPomTransformer
      implements PomTransformer
  {
      /** POM document */
      private File project;
  
      /** Dom4j document. */
      private Document document;
  
      /** Output file. */
      private File outputFile;
  
      /** Properties used in transformNode */
      private Map variables;
  
      /** Nodes selected for transformation using xpath. */
      private List selectedNodes;
  
      private List transformations;
  
      // -------------------------------------------------------------------------
      // Accessors
      // -------------------------------------------------------------------------
  
      /**
       *
       * @return
       */
      public Map getVariables()
      {
          return variables;
      }
  
      /**
       *
       * @param variables
       */
      public void setVariables( Map variables )
      {
          this.variables = variables;
      }
  
      /**
       *
       * @param project
      */
     public void setProject( File project )
     {
         this.project = project;
     }
 
     /**
      *
      * @return
      */
     public File getProject()
     {
         return project;
     }
 
     /**
      *
      * @return
      */
     public Document getDocument()
     {
         return document;
     }
 
     /**
      *
      * @param document
      */
     public void setDocument( Document document )
     {
         this.document = document;
     }
 
     /**
      *
      * @return
      */
     public File getOutputFile()
     {
         return outputFile;
     }
 
     /**
      *
      * @param outputFile
      */
     public void setOutputFile( File outputFile )
     {
         this.outputFile = outputFile;
     }
 
     /**
      *
      * @return
      */
     public List getSelectedNodes()
     {
         if ( selectedNodes == null )
         {
             try
             {
                 selectNodes();
             }
             catch ( Exception e )
             {
                 // do nothing.
             }
         }
         return selectedNodes;
     }
 
     /**
      *
      * @param selectedNodes
      */
     public void setSelectedNodes( List selectedNodes )
     {
         this.selectedNodes = selectedNodes;
     }
 
     /**
      *
      * @return
      */
     public int getSelectedNodeCount()
     {
         return getSelectedNodes().size();
     }
 
     /**
      *
      * @return
      */
     public List getTransformations()
     {
         if ( transformations == null )
         {
             createTransformations();
         }
 
         return transformations;
     }
 
     /**
      *
      */
     public void createTransformations()
     {
         transformations = new ArrayList();
 
         for ( Iterator i = getSelectedNodes().iterator(); i.hasNext(); )
         {
             Object o = i.next();
 
             if ( o instanceof Node )
             {
                 Transformation transformation = new Transformation( this );
                 transformation.setNode( (Node) o );
                 transformations.add( transformation );
             }
         }
     }
 
     /**
      * This is the automated way of transforming the nodes if there is
      * no user interaction involved.
      *
      * @throws Exception If an error occurs while transforming the nodes.
      */
     public void transformNodes()
         throws Exception
     {
         for ( Iterator i = getSelectedNodes().iterator(); i.hasNext(); )
         {
             Object o = i.next();
 
             if ( o instanceof Node )
             {
                 transformNode( (Node) o );
             }
         }
     }
 
     // ----------------------------------------------------------------------
     // Implementation
     // ----------------------------------------------------------------------
 
     /**
      *
      * @return
      */
     public abstract String selectNodesXPathExpression();
 
     /**
      *
      * @param node
      * @throws Exception
      */
     public abstract void transformNode( Node node )
         throws Exception;
 
     /**
      * Update the snapshot version identifiers with actual timestamp versions
      * and write out the POM in its updated form.
      *
      * @throws Exception
      */
     public void selectNodes()
         throws Exception
     {
         SAXReader reader = new SAXReader();
 
         // make xpath expressions worh with poms with or without namespace
         reader.setXMLFilter( new XMLFilterImpl()
         {
 
             public void endElement( String uri, String localName, String qName )
                 throws SAXException
             {
                 super.endElement( "", localName, "" );
             }
 
             public void startElement( String uri, String localName, String qName, Attributes atts )
                 throws SAXException
             {
                 super.startElement( "", localName, "", atts );
             }
 
         } );
         setDocument( reader.read( getProject() ) );
 
         // The selecting nodes with the xpath expression will give us a list
         // of dependencies elements where the version element is equal to 'SNAPSHOT'.
         // So we can get any information we need, and alter anything we need to before writing
         // the dom4j document back out.
         XPath xpath = new Dom4jXPath( selectNodesXPathExpression() );
         setSelectedNodes( xpath.selectNodes( getDocument() ) );
     }
 
     /**
      *
      * @throws Exception
      */
     public void write()
         throws Exception
     {
         write( null );
     }
 
     /**
      *
      * @throws Exception
      */
     public void write( String encoding )
         throws Exception
     {
         OutputStream os = null;
 
         if ( getOutputFile() != null )
         {
             // Backup the original first.
             FileUtils.copyFile( getOutputFile(), new File( getOutputFile() + ".backup" ) );
 
             // Now hand of the os.
             os = new FileOutputStream( getOutputFile() );
         }
         else
         {
             os = new PrintStream( System.out );
         }
 
         OutputFormat format = new OutputFormat();
         format.setIndentSize( 2 );
         format.setNewlines( true );
         format.setTrimText( true );
         if ( encoding != null )
         {
             format.setEncoding( encoding );
         }
 
         XMLWriter writer = new XMLWriter( format )
         {
             protected boolean isNamespaceDeclaration( Namespace ns )
             {
                 // this will filter out empty namespaces, only the correct POM ns is allowed
                 return "http://maven.apache.org/POM/3.0.0".equals( ns.getURI() );
             }
         };
 
         writer.setOutputStream( os );
         writer.write( getDocument() );
         writer.flush();
         writer.close();
     }
 }