package org.apache.maven.plugin;
   
   /*
    * 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.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  
  import org.apache.maven.artifact.Artifact;
  import org.apache.maven.model.Plugin;
  import org.apache.maven.project.MavenProject;
  import org.codehaus.plexus.component.annotations.Component;
  import org.eclipse.aether.RepositorySystemSession;
  import org.eclipse.aether.graph.DependencyFilter;
  import org.eclipse.aether.repository.LocalRepository;
  import org.eclipse.aether.repository.RemoteRepository;
  import org.eclipse.aether.repository.WorkspaceRepository;
  
  /**
   * @author Igor Fedorenko
   * @author Benjamin Bentmann
   */
  @Component( role = PluginArtifactsCache.class )
  public class DefaultPluginArtifactsCache
      implements PluginArtifactsCache
  {
  
      protected static class CacheKey
          implements Key
      {
  
          private final Plugin plugin;
  
          private final WorkspaceRepository workspace;
  
          private final LocalRepository localRepo;
  
          private final List<RemoteRepository> repositories;
  
          private final DependencyFilter filter;
  
          private final int hashCode;
  
          public CacheKey( Plugin plugin, DependencyFilter extensionFilter, List<RemoteRepository> repositories,
                           RepositorySystemSession session )
          {
              this.plugin = plugin.clone();
              workspace = CacheUtils.getWorkspace( session );
              this.localRepo = session.getLocalRepository();
              this.repositories = new ArrayList<RemoteRepository>( repositories.size() );
              for ( RemoteRepository repository : repositories )
              {
                  if ( repository.isRepositoryManager() )
                  {
                      this.repositories.addAll( repository.getMirroredRepositories() );
                  }
                  else
                  {
                      this.repositories.add( repository );
                  }
              }
              this.filter = extensionFilter;
  
              int hash = 17;
              hash = hash * 31 + CacheUtils.pluginHashCode( plugin );
              hash = hash * 31 + hash( workspace );
              hash = hash * 31 + hash( localRepo );
              hash = hash * 31 + CacheUtils.repositoriesHashCode( repositories );
              hash = hash * 31 + hash( extensionFilter );
              this.hashCode = hash;
          }
  
          @Override
          public String toString()
          {
              return plugin.getId();
          }
  
          @Override
          public int hashCode()
         {
             return hashCode;
         }
 
         private static int hash( Object obj )
         {
             return obj != null ? obj.hashCode() : 0;
         }
 
         @Override
         public boolean equals( Object o )
         {
             if ( o == this )
             {
                 return true;
             }
 
             if ( !( o instanceof CacheKey ) )
             {
                 return false;
             }
 
             CacheKey that = (CacheKey) o;
 
             return CacheUtils.pluginEquals( plugin, that.plugin ) && eq( workspace, that.workspace )
                 && eq( localRepo, that.localRepo ) && CacheUtils.repositoriesEquals( repositories, that.repositories )
                 && eq( filter, that.filter );
         }
 
         private static <T> boolean eq( T s1, T s2 )
         {
             return s1 != null ? s1.equals( s2 ) : s2 == null;
         }
 
     }
 
     protected final Map<Key, CacheRecord> cache = new ConcurrentHashMap<Key, CacheRecord>();
 
     public Key createKey( Plugin plugin, DependencyFilter extensionFilter, List<RemoteRepository> repositories,
                           RepositorySystemSession session )
     {
         return new CacheKey( plugin, extensionFilter, repositories, session );
     }
 
     public CacheRecord get( Key key )
         throws PluginResolutionException
     {
         CacheRecord cacheRecord = cache.get( key );
 
         if ( cacheRecord != null && cacheRecord.exception != null )
         {
             throw cacheRecord.exception;
         }
 
         return cacheRecord;
     }
 
     public CacheRecord put( Key key, List<Artifact> pluginArtifacts )
     {
         if ( pluginArtifacts == null )
         {
             throw new NullPointerException();
         }
 
         assertUniqueKey( key );
 
         CacheRecord record =
             new CacheRecord( Collections.unmodifiableList( new ArrayList<Artifact>( pluginArtifacts ) ) );
 
         cache.put( key, record );
 
         return record;
     }
 
     protected void assertUniqueKey( Key key )
     {
         if ( cache.containsKey( key ) )
         {
             throw new IllegalStateException( "Duplicate artifact resolution result for plugin " + key );
         }
     }
 
     public CacheRecord put( Key key, PluginResolutionException exception )
     {
         if ( exception == null )
         {
             throw new NullPointerException();
         }
 
         assertUniqueKey( key );
 
         CacheRecord record = new CacheRecord( exception );
 
         cache.put( key, record );
 
         return record;
     }
 
     public void flush()
     {
         cache.clear();
     }
 
     protected static int pluginHashCode( Plugin plugin )
     {
         return CacheUtils.pluginHashCode( plugin );
     }
 
     protected static boolean pluginEquals( Plugin a, Plugin b )
     {
         return CacheUtils.pluginEquals( a, b );
     }
 
     public void register( MavenProject project, Key cacheKey, CacheRecord record )
     {
         // default cache does not track record usage
     }
 
 }