/*
    * Copyright 2008, 2009 Ange Optimization ApS
    *
    * 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 eu.simuline.octave.io;
  
  import static eu.simuline.octave.io.OctaveIO.readerReadLine;
  
  import java.io.BufferedReader;
  import java.io.Reader;
  import java.util.Map;
  
  import eu.simuline.octave.exception.OctaveParseException;
  import eu.simuline.octave.exec.ReadFunctor;
  import eu.simuline.octave.type.OctaveObject;
  
  /**
   * Functor that reads a single variable named {@link #name} 
   * into {@link #data} via {@link #doReads(Reader)}. 
   */
  // ER: Very strange: whereas this read functor reads a single variable only 
  // the according write functor writes a map: 
  // see OctaveIO 
  final class DataReadFunctor implements ReadFunctor {
  
      /**
       * The name of the variable to be read. 
       */
      private final String name;
  
      /**
       * After {@link #doReads(Reader)} returns, this contains the read data. 
       */
      private OctaveObject data;
  
      /**
       * @param name
       */
      DataReadFunctor(final String name) {
          this.name = name;
      }
  
      /**
       * @param reader
       */
      @Override
      public void doReads(final Reader reader) {
          final BufferedReader bufferedReader = new BufferedReader(reader);
          final String createByOctaveLine = readerReadLine(bufferedReader);
          if (createByOctaveLine == null || 
  	    !createByOctaveLine.startsWith("# Created by Octave")) {
              throw new OctaveParseException
  		("Not created by Octave?: '" + createByOctaveLine + "'");
          }
          final Map<String, OctaveObject> map = 
  	    OctaveIO.readWithName(bufferedReader);
          if (map.size() != 1) {
              throw new OctaveParseException
  		("Expected map of size 1 but got " + map + "'");
          }
          if (!map.containsKey(this.name)) {
              throw new OctaveParseException
  		("Expected variable named '" + this.name + 
  		 "' but got '" + map + "'");
          }
          this.data = map.get(this.name);
      }
  
      /**
       * @return the data
       */
      public OctaveObject getData() {
          return this.data;
      }
  
  }