package org.apache.maven.lifecycle.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.project.MavenProject;
  
  import java.util.Arrays;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.TreeSet;
  
  /**
   * Context of dependency artifacts for a particular project.
   *
   * @since 3.0
   * @author Benjamin Bentmann
   * @author Kristian Rosenvold (class extract only)
   *         <p/>
   *         NOTE: This class is not part of any public api and can be changed or deleted without prior notice.
   */
  // TODO From a concurrency perspective, this class is not good. The combination of mutable/immutable state is not nice
  public class DependencyContext
  {
  
      private static final Collection<?> UNRESOLVED = Arrays.asList();
  
      private final MavenProject project;
  
      private final Collection<String> scopesToCollectForCurrentProject;
  
      private final Collection<String> scopesToResolveForCurrentProject;
  
      private final Collection<String> scopesToCollectForAggregatedProjects;
  
      private final Collection<String> scopesToResolveForAggregatedProjects;
  
      private volatile Collection<?> lastDependencyArtifacts = UNRESOLVED;
  
      private volatile int lastDependencyArtifactCount = -1;
  
      public DependencyContext( MavenProject project, Collection<String> scopesToCollect,
                                Collection<String> scopesToResolve )
      {
          this.project = project;
          scopesToCollectForCurrentProject = scopesToCollect;
          scopesToResolveForCurrentProject = scopesToResolve;
          scopesToCollectForAggregatedProjects = Collections.synchronizedSet( new TreeSet<String>() );
          scopesToResolveForAggregatedProjects = Collections.synchronizedSet( new TreeSet<String>() );
      }
  
      public MavenProject getProject()
      {
          return project;
      }
  
      public Collection<String> getScopesToCollectForCurrentProject()
      {
          return scopesToCollectForCurrentProject;
      }
  
      public Collection<String> getScopesToResolveForCurrentProject()
      {
          return scopesToResolveForCurrentProject;
      }
  
      public Collection<String> getScopesToCollectForAggregatedProjects()
      {
          return scopesToCollectForAggregatedProjects;
      }
  
      public Collection<String> getScopesToResolveForAggregatedProjects()
      {
          return scopesToResolveForAggregatedProjects;
      }
  
      public boolean isResolutionRequiredForCurrentProject()
      {
          return lastDependencyArtifacts != project.getDependencyArtifacts() || ( lastDependencyArtifacts != null
              && lastDependencyArtifactCount != lastDependencyArtifacts.size() );
      }
  
      public boolean isResolutionRequiredForAggregatedProjects( Collection<String> scopesToCollect,
                                                               Collection<String> scopesToResolve )
     {
         boolean required =
             scopesToCollectForAggregatedProjects.addAll( scopesToCollect )
                 || scopesToResolveForAggregatedProjects.addAll( scopesToResolve );
         return required;
     }
 
     public void synchronizeWithProjectState()
     {
         lastDependencyArtifacts = project.getDependencyArtifacts();
         lastDependencyArtifactCount = ( lastDependencyArtifacts != null ) ? lastDependencyArtifacts.size() : 0;
     }
 
 }