/*

  * Copyright 2012 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.ci.config.load;

 import java.util.ArrayList;

 import java.util.List;

 import org.jdom.Document;

 import org.jdom.Element;

 import org.jdom.JDOMException;

 import org.jdom.input.SAXBuilder;

 import org.jdom.xpath.XPath;

 import org.xml.sax.InputSource;

 import de.smartics.ci.config.maven.MavenConfig;

 import de.smartics.util.lang.Arguments;

 import de.smartics.util.lang.NullArgumentException;

 /**

  * Loads {@link LoaderPlan}s from XML files.

  */

 public final class LoaderPlanLoader

 {

   // ********************************* Fields *********************************

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

   // --- members --------------------------------------------------------------

   /**

    * The Maven configuration to add to every generated loader.

    */

   private final MavenConfig mavenConfig;

   // ****************************** Initializer *******************************

   // ****************************** Constructors ******************************

   /**

    * Default constructor.

    *

    * @param mavenConfig the Maven configuration to add to every generated

    *          loader.

    */

   public LoaderPlanLoader(final MavenConfig mavenConfig)

   {

     this.mavenConfig = mavenConfig;

   }

   // ****************************** Inner Classes *****************************

   // ********************************* Methods ********************************

   // --- init -----------------------------------------------------------------

   // --- get&set --------------------------------------------------------------

   // --- business -------------------------------------------------------------

   /**

    * Loads loader plans read from the given stream.

    *

    * @param inputSource contains an <code>ci-config</code> XML document with

    *          loader information.

    * @return the loader information from the stream. May be empty, if no loader

    *         information has been found, but is never <code>null</code>.

    * @throws NullArgumentException if {@code inputSource} is <code>null</code>.

    */

   public List<LoaderPlan> load(final InputSource inputSource)

     throws NullArgumentException

   {

     Arguments.checkNotNull("inputSource", inputSource);

     final List<LoaderPlan> loaderPlans = new ArrayList<LoaderPlan>();

     final SAXBuilder builder = new SAXBuilder();

     try

     {

       final Document ciConfigXml = builder.build(inputSource);

       load(loaderPlans, ciConfigXml);

     }

     catch (final Exception e)

     {

       throw new IllegalArgumentException("Cannot load loader plan from '"

                                          + inputSource.getSystemId() + "'.", e);

     }

     return loaderPlans;

   }

   @SuppressWarnings("unchecked")

   private void load(final List<LoaderPlan> loaderPlans,

       final Document ciConfigXml) throws JDOMException

   {

     final String xPathString = "ci-config/import-definitions/import-definition";

     final List<Element> importDefinitions =

         XPath.selectNodes(ciConfigXml, xPathString);

     for (final Element importDefinition : importDefinitions)

     {

       final String id = importDefinition.getAttributeValue("id");

       final List<Element> imports = importDefinition.getChildren("import");

       final LoaderPlan plan = new LoaderPlan(id, mavenConfig);

       for (final Element singleImport : imports)

       {

         final String configurationName = singleImport.getTextTrim();

         plan.addConfigurationName(configurationName);

       }

       loaderPlans.add(plan);

     }

   }

   // --- object basics --------------------------------------------------------

 }