package org.codehaus.plexus.interpolation;
   
   /*
    * Copyright 2001-2008 Codehaus Foundation.
    *
    * 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.
   */
  
  import java.util.List;
  
  public abstract class AbstractDelegatingValueSource implements ValueSource {
  
      private final ValueSource delegate;
  
      protected AbstractDelegatingValueSource(ValueSource delegate) {
          if (delegate == null) {
              throw new NullPointerException("Delegate ValueSource cannot be null.");
          }
  
          this.delegate = delegate;
      }
  
      protected ValueSource getDelegate() {
          return delegate;
      }
  
      @Override
      public Object getValue(String expression, String delimiterStart, String delimiterEnd) {
          return getDelegate().getValue(expression, delimiterStart, delimiterEnd);
      }
  
      @Override
      public Object getValue(String expression) {
          return getDelegate().getValue(expression);
      }
  
      @Override
      public void clearFeedback() {
          delegate.clearFeedback();
      }
  
      @Override
      public List getFeedback() {
          return delegate.getFeedback();
      }
  }