package org.apache.maven.shared.transfer.dependencies.collect.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.model.Dependency;
  import org.apache.maven.model.Model;
  import org.apache.maven.project.ProjectBuildingRequest;
  import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
  import org.apache.maven.shared.transfer.dependencies.collect.CollectorResult;
  import org.apache.maven.shared.transfer.dependencies.collect.DependencyCollector;
  import org.apache.maven.shared.transfer.dependencies.collect.DependencyCollectorException;
  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.personality.plexus.lifecycle.phase.Contextualizable;
  
  /**
   * This DependencyCollector passes the request to the proper Maven 3.x implementation
   * 
   * @author Robert Scholte
   */
  @Component( role = DependencyCollector.class, hint = "default" )
  class DefaultDependencyCollector implements DependencyCollector, Contextualizable 
  {
      private PlexusContainer container;
  
      @Override
      public CollectorResult collectDependencies( ProjectBuildingRequest buildingRequest, Dependency root )
          throws DependencyCollectorException
      {
          validateParameters( buildingRequest, root );
  
          try
          {
              String hint = isMaven31() ? "maven31" : "maven3";
  
              DependencyCollector effectiveDependencyCollector = container.lookup( DependencyCollector.class, hint );
  
              return effectiveDependencyCollector.collectDependencies( buildingRequest, root );
          }
          catch ( ComponentLookupException e )
          {
              throw new DependencyCollectorException( e.getMessage(), e );
          }
      }
  
      @Override
      public CollectorResult collectDependencies( ProjectBuildingRequest buildingRequest, DependableCoordinate root )
          throws DependencyCollectorException
      {
          validateParameters( buildingRequest, root );
  
          try
          {
              String hint = isMaven31() ? "maven31" : "maven3";
  
              DependencyCollector effectiveDependencyCollector = container.lookup( DependencyCollector.class, hint );
  
              return effectiveDependencyCollector.collectDependencies( buildingRequest, root );
          }
          catch ( ComponentLookupException e )
          {
              throw new DependencyCollectorException( e.getMessage(), e );
          }
      }
  
      @Override
      public CollectorResult collectDependencies( ProjectBuildingRequest buildingRequest, Model root )
          throws DependencyCollectorException
      {
          validateParameters( buildingRequest, root );
  
          try
          {
              String hint = isMaven31() ? "maven31" : "maven3";
  
              DependencyCollector effectiveDependencyCollector = container.lookup( DependencyCollector.class, hint );
  
              return effectiveDependencyCollector.collectDependencies( buildingRequest, root );
         }
         catch ( ComponentLookupException e )
         {
             throw new DependencyCollectorException( e.getMessage(), e );
         }
     }
 
     private void validateParameters( ProjectBuildingRequest buildingRequest, DependableCoordinate root )
     {
         validateBuildingRequest( buildingRequest );
         if ( root == null )
         {
             throw new IllegalArgumentException( "The parameter root is not allowed to be null." );
         }
     }
 
     private void validateParameters( ProjectBuildingRequest buildingRequest, Dependency root )
     {
         validateBuildingRequest( buildingRequest );
         if ( root == null )
         {
             throw new IllegalArgumentException( "The parameter root is not allowed to be null." );
         }
     }
 
     private void validateParameters( ProjectBuildingRequest buildingRequest, Model root )
     {
         validateBuildingRequest( buildingRequest );
         if ( root == null )
         {
             throw new IllegalArgumentException( "The parameter root is not allowed to be null." );
         }
     }
 
     private void validateBuildingRequest( ProjectBuildingRequest buildingRequest )
     {
         if ( buildingRequest == null )
         {
             throw new IllegalArgumentException( "The parameter buildingRequest is not allowed to be null." );
         }
     }
 
     /**
      * @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 );
     }
 
 }