package org.apache.maven.plugin.dependency;
   
   /*
    * 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.Reader;
  import java.util.ArrayList;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Set;
  
  import org.apache.commons.collections.CollectionUtils;
  import org.apache.maven.model.Dependency;
  import org.apache.maven.model.Model;
  import org.apache.maven.model.io.xpp3.MavenXpp3Reader;
  import org.apache.maven.plugin.AbstractMojo;
  import org.apache.maven.plugin.MojoExecutionException;
  import org.apache.maven.plugin.MojoFailureException;
  import org.apache.maven.project.MavenProject;
  import org.codehaus.plexus.util.IOUtil;
  import org.codehaus.plexus.util.ReaderFactory;
  
  /**
   * Analyzes the <code>&lt;dependencies/&gt;</code> and <code>&lt;dependencyManagement/&gt;</code> tags in the
   * <code>pom.xml</code> and determines the duplicate declared dependencies.
   *
   * @author <a href="mailto:vincent.siveton@gmail.com">Vincent Siveton</a>
   * @version $Id: AnalyzeDuplicateMojo.java 1085777 2011-03-26 18:13:19Z hboutemy $
   * @goal analyze-duplicate
   * @aggregator false
   */
  public class AnalyzeDuplicateMojo
      extends AbstractMojo
  {
      /**
       * The Maven project to analyze.
       *
       * @parameter expression="${project}"
       * @required
       * @readonly
       */
      private MavenProject project;
  
      /** {@inheritDoc} */
      public void execute()
          throws MojoExecutionException, MojoFailureException
      {
          MavenXpp3Reader pomReader = new MavenXpp3Reader();
          Model model = null;
          Reader reader = null;
          try
          {
              reader = ReaderFactory.newXmlReader( project.getFile() );
              model = pomReader.read( reader );
          }
          catch ( Exception e )
          {
              throw new MojoExecutionException( "IOException: " + e.getMessage(), e );
          }
          finally
          {
              IOUtil.close( reader );
          }
  
          Set<String> duplicateDependencies = new HashSet<String>();
          if ( model.getDependencies() != null )
          {
              duplicateDependencies = findDuplicateDependencies( model.getDependencies() );
          }
  
          Set<String> duplicateDependenciesManagement = new HashSet<String>();
          if ( model.getDependencyManagement() != null && model.getDependencyManagement().getDependencies() != null )
          {
              duplicateDependenciesManagement =
                  findDuplicateDependencies( model.getDependencyManagement().getDependencies() );
          }
  
          if ( getLog().isInfoEnabled() )
          {
              StringBuffer sb = new StringBuffer();
  
              if ( !duplicateDependencies.isEmpty() )
             {
                 sb.append( "List of duplicate dependencies defined in <dependencies/> in your pom.xml:\n" );
                 for ( Iterator<String> it = duplicateDependencies.iterator(); it.hasNext(); )
                 {
                     String dup = it.next();
 
                     sb.append( "\to " + dup );
                     if ( it.hasNext() )
                     {
                         sb.append( "\n" );
                     }
                 }
             }
 
             if ( !duplicateDependenciesManagement.isEmpty() )
             {
                 if ( sb.length() > 0 )
                 {
                     sb.append( "\n" );
                 }
                 sb.append( "List of duplicate dependencies defined in <dependencyManagement/> in "
                     + "your pom.xml:\n" );
                 for ( Iterator<String> it = duplicateDependenciesManagement.iterator(); it.hasNext(); )
                 {
                     String dup = it.next();
 
                     sb.append( "\to " + dup );
                     if ( it.hasNext() )
                     {
                         sb.append( "\n" );
                     }
                 }
             }
 
             if ( sb.length() > 0 )
             {
                 getLog().info( sb.toString() );
             }
             else
             {
                 getLog().info( "No duplicate dependencies found in <dependencies/> or in <dependencyManagement/>" );
             }
         }
     }
 
     private Set<String> findDuplicateDependencies( List<Dependency> modelDependencies )
     {
         List<String> modelDependencies2 = new ArrayList<String>();
         for ( Dependency dep : modelDependencies )
         {
             modelDependencies2.add( dep.getManagementKey() );
         }
 
         return new HashSet<String>( CollectionUtils.disjunction( modelDependencies2,
                                                                  new HashSet<String>( modelDependencies2 ) ) );
     }
 }