package org.apache.maven.shared.runtime;

 /*

  * 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.io.IOException;

 import java.io.InputStream;

 import java.net.URL;

 import java.net.URLConnection;

 import java.util.ArrayList;

 import java.util.Collections;

 import java.util.List;

 import java.util.Properties;

 import org.codehaus.plexus.util.IOUtil;

 /**

  * A visitor that parses and collects Maven project property files.

  * 

  * @author <a href="mailto:markh@apache.org">Mark Hobson</a>

  * @version $Id: PropertiesMavenRuntimeVisitor.java 831910 2009-11-02 15:05:33Z markh $

  */

 class PropertiesMavenRuntimeVisitor implements MavenRuntimeVisitor

 {

     // constants --------------------------------------------------------------

     /**

      * The group id property name in a Maven project property file.

      */

     private static final String GROUP_ID_PROPERTY = "groupId";

     /**

      * The artifact id property name in a Maven project property file.

      */

     private static final String ARTIFACT_ID_PROPERTY = "artifactId";

     /**

      * The version property name in a Maven project property file.

      */

     private static final String VERSION_PROPERTY = "version";

     // fields -----------------------------------------------------------------

     /**

      * A list of the collected project properties.

      */

     private final List<MavenProjectProperties> projects;

     // constructors -----------------------------------------------------------

     /**

      * Creates a new {@code PropertiesMavenRuntimeVisitor}.

      */

     public PropertiesMavenRuntimeVisitor()

     {

         projects = new ArrayList<MavenProjectProperties>();

     }

     // MavenRuntimeVisitor methods --------------------------------------------

     /**

      * {@inheritDoc}

      */

     public void visitProjectProperties( URL url ) throws MavenRuntimeException

     {

         MavenProjectProperties project = parseProjectProperties( url );

         projects.add( project );

     }

     /**

      * {@inheritDoc}

      */

     public void visitProjectXML( URL url ) throws MavenRuntimeException

     {

         // no-op

     }

     // public methods ---------------------------------------------------------

     /**

      * Gets the collected Maven project properties.

      * 

      * @return a list of the collected project properties

      */

     public List<MavenProjectProperties> getProjects()

     {

         return Collections.unmodifiableList( projects );

     }

     // private methods --------------------------------------------------------

     /**

      * Parses the specified Maven project properties into a {@code MavenProjectProperties} object.

      * 

      * @param url

      *            a URL to the Maven project properties

      * @return a {@code MavenProjectProperties} object that represents the properties

      * @throws MavenRuntimeException

      *             if an error occurs parsing the properties

      */

     private MavenProjectProperties parseProjectProperties( URL url ) throws MavenRuntimeException

     {

         Properties properties = new Properties();

         InputStream in = null;

         try

         {

             URLConnection connection = url.openConnection();

             connection.setUseCaches( false );

             in = connection.getInputStream();

             properties.load( in );

         }

         catch ( IOException exception )

         {

             throw new MavenRuntimeException( "Cannot read project properties: " + url, exception );

         }

         finally

         {

             IOUtil.close( in );

         }

         String groupId = properties.getProperty( GROUP_ID_PROPERTY );

         String artifactId = properties.getProperty( ARTIFACT_ID_PROPERTY );

         String version = properties.getProperty( VERSION_PROPERTY );

         return new MavenProjectProperties( groupId, artifactId, version );

     }

 }