package org.apache.maven.plugin.dependency;
   
   /*
    * Copyright 2001-2005 The Apache Software Foundation.
    *
    * 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.
   */
  
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.List;
  
  import org.apache.maven.artifact.Artifact;
  import org.apache.maven.artifact.factory.ArtifactFactory;
  import org.apache.maven.artifact.metadata.ArtifactMetadataSource;
  import org.apache.maven.artifact.repository.ArtifactRepository;
  import org.apache.maven.artifact.repository.ArtifactRepositoryFactory;
  import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
  import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
  import org.apache.maven.artifact.repository.layout.DefaultRepositoryLayout;
  import org.apache.maven.artifact.resolver.AbstractArtifactResolutionException;
  import org.apache.maven.artifact.resolver.ArtifactResolver;
  import org.apache.maven.plugin.AbstractMojo;
  import org.apache.maven.plugin.MojoExecutionException;
  import org.apache.maven.plugin.MojoFailureException;
  import org.codehaus.plexus.util.StringUtils;
  
  /**
   * Downloads a single artifact transitively from a specified remote repository.
   *
   * @goal get
   * @requiresProject false
   * 
   */
  public class GetMojo
      extends AbstractMojo
  {
      
      /**
       * @component
       * @readonly
       */
      private ArtifactFactory artifactFactory;
      
      /**
       * @component
       * @readonly
       */
      private ArtifactResolver artifactResolver;
      
      /**
       * @component
       * @readonly
       */
      private ArtifactRepositoryFactory artifactRepositoryFactory;
      
      /**
       * @component
       * @readonly
       */
      private ArtifactMetadataSource source;
      
      /**
       * 
       * @parameter expression="${localRepository}"
       * @readonly
       */
      private ArtifactRepository localRepository;
  
      /**
       * The groupId of the artifact to download
       * @parameter expression="${groupId}"
       */
      private String groupId;
  
      /**
       * The artifactId of the artifact to download
       * @parameter expression="${artifactId}"
       */
      private String artifactId;
  
      /**
       * The version of the artifact to download
       * @parameter expression="${version}"
       */
      private String version;
  
      /**
      * The packaging of the artifact to download
      * @parameter expression="${packaging}" default-value="jar"
      */
     private String packaging = "jar";
 
     /**
      * The id of the repository from which we'll download the artifact
      * @parameter expression="${repoId}" default-value="temp"
      */
     private String repositoryId = "temp";
 
     /**
      * The url of the repository from which we'll download the artifact
      * @parameter expression="${repoUrl}"
      * @required
      */
     private String repositoryUrl;
 
     /**
      * @parameter expression="${remoteRepositories}"
      * @readonly
      */
     private String remoteRepositories;
     
     /**
      * A string of the form groupId:artifactId:version[:packaging].
      * @parameter expression="${artifact}"
      */
     private String artifact;
     
     /**
      * 
      * @parameter expression="${project.remoteArtifactRepositories}"
      * @required
      * @readonly
      */
     private List pomRemoteRepositories;
     
     /**
      * Download transitively, retrieving the specified artifact and all of its dependencies.
      * @parameter expression="{$transitive}" default-value=true
      */
     private boolean transitive = true;
     
     public void execute()
         throws MojoExecutionException, MojoFailureException
     {        
 
         if ( artifactId == null && artifact == null )
             throw new MojoFailureException( "You must specify an artifact, "
                 + "e.g. -Dartifact=org.apache.maven.plugins:maven-downloader-plugin:1.0" );
         if ( artifactId == null )
         {
             String[] tokens = StringUtils.split( artifact, ":" );
             if ( tokens.length != 3 && tokens.length != 4 )
                 throw new MojoFailureException( "Invalid artifact, you must specify "
                     + "groupId:artifactId:version[:packaging] " + artifact );
             groupId = tokens[0];
             artifactId = tokens[1];
             version = tokens[2];
             if ( tokens.length == 4 )
                 packaging = tokens[3];
         }
         Artifact toDownload = artifactFactory.createBuildArtifact( groupId, artifactId, version, packaging );
         Artifact dummyOriginatingArtifact =
             artifactFactory.createBuildArtifact( "org.apache.maven.plugins", "maven-downloader-plugin", "1.0", "jar" );
 
         ArtifactRepositoryLayout repositoryLayout = new DefaultRepositoryLayout();
         ArtifactRepositoryPolicy always =
             new ArtifactRepositoryPolicy( true, ArtifactRepositoryPolicy.UPDATE_POLICY_ALWAYS,
                                           ArtifactRepositoryPolicy.CHECKSUM_POLICY_WARN );
         ArtifactRepository remoteRepo =
             artifactRepositoryFactory.createArtifactRepository( repositoryId, repositoryUrl, repositoryLayout, always,
                                                                 always );
 
         if ( pomRemoteRepositories == null )
             pomRemoteRepositories = new ArrayList();
 
         List repoList = new ArrayList( pomRemoteRepositories );
         if ( remoteRepositories != null )
         {
 
             repoList.addAll( Arrays.asList( StringUtils.split( remoteRepositories, "," ) ) );
 
         }
 
         repoList.add( remoteRepo );
 
         try
         {
             if ( transitive )
             {
                 artifactResolver.resolveTransitively( Collections.singleton( toDownload ), dummyOriginatingArtifact,
                                                       repoList, localRepository, source );
             }
             else
             {
                 artifactResolver.resolve ( toDownload, repoList, localRepository );
             }
             
         }
         catch ( AbstractArtifactResolutionException e )
         {
             throw new MojoExecutionException( "Couldn't download artifact: " + e.getMessage(), e );
         }
     }
 }