/*
    * Copyright 2012-2013 smartics, Kronseder & Reiner GmbH
    *
    * 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.
   */
  package de.smartics.properties.resource.repository;
  
  import java.io.Serializable;
  import java.net.URL;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  import javax.annotation.CheckForNull;
  import javax.annotation.concurrent.NotThreadSafe;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import de.smartics.util.lang.Arguments;
  
  /**
   * Defines the environment of class path resources to access.
   */
  @NotThreadSafe
  public final class ClassPathEnvironment implements Serializable
  {
    // ********************************* Fields *********************************
  
    // --- constants ------------------------------------------------------------
  
    /**
     * The class version identifier.
     */
    private static final long serialVersionUID = 1L;
  
    /**
     * Reference to the logger for this class.
     */
    private static final Logger LOG = LoggerFactory
        .getLogger(ClassPathEnvironment.class);
  
    // --- members --------------------------------------------------------------
  
    /**
     * The map of artifact IDs (GAV concatenated and separated by colons) to the
     * artifact references.
     */
    private final Map<String, ArtifactRef> index =
        new HashMap<String, ArtifactRef>();
  
    /**
     * The list of artifact references found on this class path.
     *
     * @serial
     */
    private final List<ArtifactRef> artifactRefs = new ArrayList<ArtifactRef>();
  
    // ****************************** Initializer *******************************
  
    // ****************************** Constructors ******************************
  
    /**
     * Default constructor.
     */
    public ClassPathEnvironment()
    {
    }
  
    /**
     * Convenience constructor that allows to add artifact references to create an
     * initial list.
     *
     * @param artifactRefs the initial collection of artifact references to add as
     *          roots.
     */
    public ClassPathEnvironment(final ArtifactRef... artifactRefs)
    {
      this();
  
      for (final ArtifactRef artifactRef : artifactRefs)
      {
        addArtifactRef(artifactRef);
      }
    }
  
    /**
    * Convenience constructor that allows to add artifact references to create an
    * initial list.
    *
    * @param artifactRefs the initial collection of artifact references to add as
    *          roots.
    */
   public ClassPathEnvironment(final List<ArtifactRef> artifactRefs)
   {
     for (final ArtifactRef artifactRef : artifactRefs)
     {
       addArtifactRef(artifactRef);
     }
   }
 
   // ****************************** Inner Classes *****************************
 
   // ********************************* Methods ********************************
 
   // --- init -----------------------------------------------------------------
 
   // --- get&set --------------------------------------------------------------
 
   // --- business -------------------------------------------------------------
   /**
    * Returns a list of artifact references.
    *
    * @return an unmodifiable list of artifact references registered in this
    *         environment.
    */
   public List<ArtifactRef> getArtifactRefs()
   {
     return Collections.unmodifiableList(artifactRefs);
   }
 
   /**
    * Returns a list of URLs that point to the physical locations of the
    * artifacts.
    *
    * @return a list of URLs that point to the physical locations of the
    *         artifacts.
    */
   public List<URL> getUrls()
   {
     final List<URL> urls = new ArrayList<URL>(artifactRefs.size());
     for (final URL url : urls)
     {
       urls.add(url);
     }
 
     return urls;
   }
 
   /**
    * Returns the artifact reference by its short ID.
    *
    * @param artifactId the GAV concatenated and separated by colons.
    * @return the associated artifact reference or <code>null</code> if there is
    *         no artifact reference with the given {@code artifactId} registered.
    * @throws NullPointerException if {@code artifactId} is <code>null</code>.
    */
   @CheckForNull
   public ArtifactRef getArtifactRef(final String artifactId)
     throws NullPointerException
   {
     Arguments.checkNotNull("artifactId", artifactId);
 
     return index.get(artifactId);
   }
 
   /**
    * Adds the given artifact reference to the list of artifact references. All
    * references are considered to be roots to search for class path resources.
    *
    * @param artifactRef the artifact reference to add.
    * @throws NullPointerException if {@code artifactRef} is <code>null</code>.
    */
   public void addArtifactRef(final ArtifactRef artifactRef)
     throws NullPointerException
   {
     Arguments.checkNotNull("artifactRef", artifactRef);
 
     if (!artifactRef.isArchive())
     {
       LOG.debug("Dropping '" + artifactRef + "' since it is not an archive.");
       return;
     }
 
     artifactRefs.add(artifactRef);
     final String artifactId = artifactRef.getId().toShortString();
     index.put(artifactId, artifactRef);
   }
 
   // --- object basics --------------------------------------------------------
 
   /**
    * Returns the string representation of the object.
    *
    * @return the string representation of the object.
    */
   @Override
   public String toString()
   {
     final StringBuilder buffer = new StringBuilder();
 
     buffer.append("Class path roots:");
 
     for (final ArtifactRef artifactRef : artifactRefs)
     {
       buffer.append(' ').append(artifactRef);
     }
 
     return buffer.toString();
   }
 }