/*

  * Copyright 2008, 2012 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 java.io.IOException;

 import java.io.Writer;

 import java.util.Map;

 import eu.simuline.octave.exception.OctaveIOException;

 import eu.simuline.octave.exec.WriteFunctor;

 import eu.simuline.octave.type.OctaveObject;

 import org.apache.commons.logging.Log;

 import org.apache.commons.logging.LogFactory;

 /**

  * Write data from {@link OctaveObject}s into a {@link Map}. 

  */

 // ER: Very strange: whereas this write functor writes a map, 

 // the according read functor reads a single variable only: 

 // see OctaveIO 

 final class DataWriteFunctor implements WriteFunctor {

     private static final String MSG_IOE_UNEXP = "Unexpected IOException";

     private static final Log LOG = LogFactory.getLog(DataWriteFunctor.class);

     /**

      * A map from variable names to according octave objects. 

      */

     private final Map<String, OctaveObject> varName2Value;

     /**

      * @param varName2Value

      *    A map from variable names to according octave objects. 

      */

     DataWriteFunctor(final Map<String, OctaveObject> varName2Value) {

         this.varName2Value = varName2Value;

     }

     /**

      * Writes the name-value pairs of map {@link #varName2Value} 

      * to <code>writer</code>. 

      *

      * @param writer

      *    the writer this variable to value configuration is to be written to. 

      */

     public void doWrites(final Writer writer) {

         try {

             // Enter octave in "read data from input mode"

             LOG.trace("write: 'load(\"-text\", \"-\")' " + 

                       "to start read data from input mode");

             writer.write("load(\"-text\", \"-\")\n");

             // Push the data into octave

             for (final Map.Entry<String, OctaveObject> entry 

                      : this.varName2Value.entrySet()) {

                 final String        name = entry.getKey();

                 final OctaveObject value = entry.getValue();

                 if (LOG.isTraceEnabled()) {

                     LOG.trace("write: variable '" + name + 

                               "', value=<<<" + value + ">>>");

                 }

                 OctaveIO.write(writer, name, value);

             }

             // Exit octave from read data mode

             LOG.trace("write: '# name:' to exit octave from read data mode");

             writer.write("# name: \n");

             writer.flush();

         } catch (final IOException e) {

             // Will happen when we write to a dead octave process

             LOG.debug(MSG_IOE_UNEXP, e);

             throw new OctaveIOException(MSG_IOE_UNEXP, e);

         }

     }

 }