/*

  * 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.exec;

 import java.io.BufferedReader;

 import java.io.IOException;

 import java.io.Reader;

 import java.util.concurrent.Callable;

 import eu.simuline.octave.exception.OctaveIOException;

 import org.apache.commons.logging.Log;

 import org.apache.commons.logging.LogFactory;

 /**

  * Callable that reads from the octave process. 

  * Used in {@link OctaveExec#evalRW(WriteFunctor, ReadFunctor)} only. 

  */

 final class OctaveReaderCallable implements Callable<Void> {

     private static final String MSG_IOE_READ = 

         "IOException from ReadFunctor";

     private static final String MSG_IOE_CLS = 

         "IOException during close";

     private static final Log LOG = LogFactory

         .getLog(OctaveReaderCallable.class);

     private final BufferedReader processReader;

     private final ReadFunctor readFunctor;

     private final String spacer;

     /**

      * @param processReader

      * @param readFunctor

      * @param spacer

      */

     OctaveReaderCallable(final BufferedReader processReader, 

                          final ReadFunctor readFunctor, 

                          final String spacer) {

         this.processReader = processReader;

         this.readFunctor   = readFunctor;

         this.spacer        = spacer;

     }

     /**

      * Calling reads from an {@link OctaveExecuteReader} 

      * made up from {@link #processReader} 

      * with end of stream sign {@link #spacer}. 

      * Exceptions are logged on {@link #LOG}. 

      *

      * @throws OctaveIOException 

      *    if underlying readers/read functors 

      *    have thrown an {@link IOException}. 

      */

     @Override

     public Void call() {

         final Reader reader = new OctaveExecuteReader(this.processReader, 

                                                       this.spacer);

         try {

             this.readFunctor.doReads(reader);

         } catch (final IOException e) {

             LOG.debug(MSG_IOE_READ, e);

             throw new OctaveIOException(MSG_IOE_READ, e);

         } finally { // NOPMD

             try {

                 reader.close();

             } catch (final IOException e) {

                 LOG.debug(MSG_IOE_CLS, e);

                 throw new OctaveIOException(MSG_IOE_CLS, e);

             }

         }

         return null;

     }

 }