package org.apache.maven.shared.dependency.graph.internal;
   
   /*
    * 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.artifact.resolver.filter.ArtifactFilter;
  import org.apache.maven.project.MavenProject;
  import org.apache.maven.shared.dependency.graph.DependencyGraphBuilder;
  import org.apache.maven.shared.dependency.graph.DependencyGraphBuilderException;
  import org.apache.maven.shared.dependency.graph.DependencyNode;
  import org.codehaus.plexus.PlexusConstants;
  import org.codehaus.plexus.PlexusContainer;
  import org.codehaus.plexus.component.annotations.Component;
  import org.codehaus.plexus.component.repository.exception.ComponentLookupException;
  import org.codehaus.plexus.context.Context;
  import org.codehaus.plexus.context.ContextException;
  import org.codehaus.plexus.logging.AbstractLogEnabled;
  import org.codehaus.plexus.personality.plexus.lifecycle.phase.Contextualizable;
  
  import java.util.Collection;
  import java.util.Collections;
  
  /**
   * Default dependency graph builder that detects current Maven version to delegate to either Maven 2 or Maven 3 specific
   * code.
   *
   * @see Maven2DependencyGraphBuilder
   * @see Maven3DependencyGraphBuilder
   * @author Hervé Boutemy
   * @since 2.0
   */
  @Component( role = DependencyGraphBuilder.class )
  public class DefaultDependencyGraphBuilder
      extends AbstractLogEnabled
      implements DependencyGraphBuilder, Contextualizable
  {
      protected PlexusContainer container;
  
      /**
       * Builds a dependency graph.
       *
       * @param project the project
       * @param filter artifact filter (can be <code>null</code>)
       * @return DependencyNode containing the dependency graph.
       * @throws DependencyGraphBuilderException if some of the dependencies could not be resolved.
       */
      public DependencyNode buildDependencyGraph( MavenProject project, ArtifactFilter filter )
          throws DependencyGraphBuilderException
      {
          return buildDependencyGraph( project, filter, null );
      }
  
      /**
       * Builds a dependency graph.
       *
       * @param project the project
       * @param filter artifact filter (can be <code>null</code>)
       * @param reactorProjects Collection of those projects contained in the reactor (can be <code>null</code>)
       * @return DependencyNode containing the dependency graph.
       * @throws DependencyGraphBuilderException if some of the dependencies could not be resolved.
       */
      public DependencyNode buildDependencyGraph( MavenProject project, ArtifactFilter filter,
                                                  Collection<MavenProject> reactorProjects )
          throws DependencyGraphBuilderException
      {
          try
          {
              String hint = isMaven31() ? "maven31" : isMaven2x() ? "maven2" : "maven3";
  
              DependencyGraphBuilder effectiveGraphBuilder =
                  (DependencyGraphBuilder) container.lookup( DependencyGraphBuilder.class.getCanonicalName(), hint );
              getLogger().debug( "building " + hint + " dependency graph for " + project.getId() + " with "
                                     + effectiveGraphBuilder.getClass().getSimpleName() );
  
              return effectiveGraphBuilder.buildDependencyGraph( project, filter, reactorProjects );
          }
          catch ( ComponentLookupException e )
          {
              throw new DependencyGraphBuilderException( e.getMessage(), e );
          }
      }
  
      /**
      * @return true if the current Maven is Maven 2.x.
      */
     protected static boolean isMaven2x()
     {
         return !canFindCoreClass( "org.apache.maven.project.DependencyResolutionRequest" ); // Maven 3 specific
     }
 
     /**
      * @return true if the current Maven version is Maven 3.1.
      */
     protected static boolean isMaven31()
     {
         return canFindCoreClass( "org.eclipse.aether.artifact.Artifact" ); // Maven 3.1 specific
     }
 
     private static boolean canFindCoreClass( String className )
     {
         try
         {
             Thread.currentThread().getContextClassLoader().loadClass( className );
 
             return true;
         }
         catch ( ClassNotFoundException e )
         {
             return false;
         }
     }
 
     /**
      * Injects the Plexus content.
      *
      * @param context   Plexus context to inject.
      * @throws ContextException if the PlexusContainer could not be located.
      */
     public void contextualize( Context context )
         throws ContextException
     {
         container = (PlexusContainer) context.get( PlexusConstants.PLEXUS_KEY );
     }
 }