/*

  * 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.domain;

 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.Arg;

 /**

  * 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)

     {

       addArchiveArtifactRef(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)

     {

       addArchiveArtifactRef(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 ArtifactRef ref : artifactRefs)

     {

       final URL url = ref.getUrl();

       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

   {

     Arg.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.

    * <p>

    * If {@code archiveArtifactRef} is not an {@link ArtifactRef#isArchive()

    * archive}, it will <strong>not be added</strong>.

    * </p>

    *

    * @param archiveArtifactRef the artifact reference to add.

    * @throws NullPointerException if {@code archiveArtifactRef} is

    *           <code>null</code>.

    */

   public void addArchiveArtifactRef(final ArtifactRef archiveArtifactRef)

     throws NullPointerException

   {

     Arg.checkNotNull("archiveArtifactRef", archiveArtifactRef);

     if (!archiveArtifactRef.isArchive())

     {

       LOG.debug("Dropping '" + archiveArtifactRef

                 + "' since it is not an archive.");

       return;

     }

     artifactRefs.add(archiveArtifactRef);

     final String artifactId = archiveArtifactRef.getId().toShortString();

     index.put(artifactId, archiveArtifactRef);

   }

   /**

    * 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 addAnyArtifactRef(final ArtifactRef artifactRef)

     throws NullPointerException

   {

     Arg.checkNotNull("artifactRef", artifactRef);

     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();

   }

 }