package org.apache.maven.model.interpolation;
   
   /*
    * 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.util.List;
  
  import org.apache.maven.model.building.ModelProblemCollector;
  import org.apache.maven.model.building.ModelProblem.Severity;
  import org.codehaus.plexus.interpolation.ValueSource;
  
  /**
   * Wraps another value source and intercepts interpolated expressions, checking for problems.
   * 
   * @author Benjamin Bentmann
   */
  class ProblemDetectingValueSource
      implements ValueSource
  {
  
      private final ValueSource valueSource;
  
      private final String bannedPrefix;
  
      private final String newPrefix;
  
      private final ModelProblemCollector problems;
  
      public ProblemDetectingValueSource( ValueSource valueSource, String bannedPrefix, String newPrefix,
                                          ModelProblemCollector problems )
      {
          this.valueSource = valueSource;
          this.bannedPrefix = bannedPrefix;
          this.newPrefix = newPrefix;
          this.problems = problems;
      }
  
      public Object getValue( String expression )
      {
          Object value = valueSource.getValue( expression );
  
          if ( value != null && expression.startsWith( bannedPrefix ) )
          {
              String msg = "The expression ${" + expression + "} is deprecated.";
              if ( newPrefix != null && newPrefix.length() > 0 )
              {
                  msg += " Please use ${" + newPrefix + expression.substring( bannedPrefix.length() ) + "} instead.";
              }
              problems.add( Severity.WARNING, msg, null, null );
          }
  
          return value;
      }
  
      @SuppressWarnings( "unchecked" )
      public List getFeedback()
      {
          return valueSource.getFeedback();
      }
  
      public void clearFeedback()
      {
          valueSource.clearFeedback();
      }
  
  }