package org.apache.maven.model.building;
   
   /*
    * 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.PrintWriter;
  import java.io.StringWriter;
  import java.util.Collections;
  import java.util.List;
  
  import org.apache.maven.model.Model;
  
  /**
   * Signals one ore more errors during model building. The model builder tries to collect as many problems as possible
   * before eventually failing to provide callers with rich error information. Use {@link #getProblems()} to query the
   * details of the failure.
   * 
   * @author Benjamin Bentmann
   */
  public class ModelBuildingException
      extends Exception
  {
  
      private final ModelBuildingResult result;
  
      /**
       * Creates a new exception with the specified problems.
       * 
       * @param model The model that could not be built, may be {@code null}.
       * @param modelId The identifier of the model that could not be built, may be {@code null}.
       * @param problems The problems that causes this exception, may be {@code null}.
       * @deprecated Use {@link #ModelBuildingException(ModelBuildingResult)} instead.
       */
      @Deprecated
      public ModelBuildingException( Model model, String modelId, List<ModelProblem> problems )
      {
          super( toMessage( modelId, problems ) );
  
          if ( model != null )
          {
              DefaultModelBuildingResult tmp = new DefaultModelBuildingResult();
              if ( modelId == null )
              {
                  modelId = "";
              }
              tmp.addModelId( modelId );
              tmp.setRawModel( modelId, model );
              tmp.setProblems( problems );
              result = tmp;
          }
          else
          {
              result = null;
          }
      }
  
      /**
       * Creates a new exception from the specified interim result and its associated problems.
       * 
       * @param result The interim result, may be {@code null}.
       */
      public ModelBuildingException( ModelBuildingResult result )
      {
          super( toMessage( result ) );
          this.result = result;
      }
  
      /**
       * Gets the interim result of the model building up to the point where it failed.
       * 
       * @return The interim model building result or {@code null} if not available.
       */
      public ModelBuildingResult getResult()
      {
          return result;
      }
  
      /**
       * Gets the model that could not be built properly.
       * 
       * @return The erroneous model or {@code null} if not available.
       */
      public Model getModel()
     {
         if ( result == null )
         {
             return null;
         }
         if ( result.getEffectiveModel() != null )
         {
             return result.getEffectiveModel();
         }
         return result.getRawModel();
     }
 
     /**
      * Gets the identifier of the POM whose effective model could not be built. The general format of the identifier is
      * {@code <groupId>:<artifactId>:<version>} but some of these coordinates may still be unknown at the point the
      * exception is thrown so this information is merely meant to assist the user.
      * 
      * @return The identifier of the POM or an empty string if not known, never {@code null}.
      */
     public String getModelId()
     {
         if ( result == null || result.getModelIds().isEmpty() )
         {
             return "";
         }
         return result.getModelIds().get( 0 );
     }
 
     /**
      * Gets the problems that caused this exception.
      * 
      * @return The problems that caused this exception, never {@code null}.
      */
     public List<ModelProblem> getProblems()
     {
         if ( result == null )
         {
             return Collections.emptyList();
         }
         return result.getProblems();
     }
 
     private static String toMessage( ModelBuildingResult result )
     {
         if ( result != null && !result.getModelIds().isEmpty() )
         {
             return toMessage( result.getModelIds().get( 0 ), result.getProblems() );
         }
         return null;
     }
 
     private static String toMessage( String modelId, List<ModelProblem> problems )
     {
         StringWriter buffer = new StringWriter( 1024 );
 
         PrintWriter writer = new PrintWriter( buffer );
 
         writer.print( problems.size() );
         writer.print( ( problems.size() == 1 ) ? " problem was " : " problems were " );
         writer.print( "encountered while building the effective model" );
         if ( modelId != null && modelId.length() > 0 )
         {
             writer.print( " for " );
             writer.print( modelId );
         }
         writer.println();
 
         for ( ModelProblem problem : problems )
         {
             writer.print( "[" );
             writer.print( problem.getSeverity() );
             writer.print( "] " );
             writer.print( problem.getMessage() );
             writer.print( " @ " );
             writer.println( ModelProblemUtils.formatLocation( problem, modelId ) );
         }
 
         return buffer.toString();
     }
 
 }