/*

  * Copyright 2007, 2008 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.

  */

 /** 

  * @author Kim Hansen

  */

 package eu.simuline.octave.util;

 import java.io.IOException;

 import java.io.Writer;

 import org.apache.commons.logging.LogFactory;

 import org.apache.commons.logging.Log;

 /**

  * Executes the actions on a single writer to multiple writers.

  * 

  * If the list of writers in the constructor is empty 

  * everything that is written will be discarted.

  * 

  * If there is thrown one or more exception all writers will still be accessed, 

  * the exceptions will be logged and the last exception thrown 

  * will be passed on outside.

  */

 public final class TeeWriter extends Writer {

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

     private final Writer[] writers;

     /**

      * Create a writer that doesn't do anything.

      */

     public TeeWriter() {

 //        this.writers = new Writer[0];

         this(new Writer[0]);

     }

     /**

      * Create a single writer that writes to multiple writers.

      * 

      * @param writers

      *            the list of writers that should be written to.

      */

     public TeeWriter(final Writer... writers) {

         this.writers = writers;

     }

     @Override

     public void write(final char[] cbuf, final int off, final int len) 

         throws IOException {

         IOException ioe = null;

         for (final Writer writer : writers) {

             try {

                 writer.write(cbuf, off, len);

             } catch (final IOException e) {

                 LOG.debug("Exception during write()", e);

                 ioe = e;

             }

         }

         if (ioe != null) {

             throw ioe;

         }

     }

     @Override

     public void flush() throws IOException {

         IOException ioe = null;

         for (final Writer writer : writers) {

             try {

                 writer.flush();

             } catch (final IOException e) {

                 LOG.debug("Exception during flush()", e);

                 ioe = e;

             }

         }

         if (ioe != null) {

             throw ioe;

         }

     }

     @Override

     public void close() throws IOException {

         IOException ioe = null;

         for (final Writer writer : writers) {

             try {

                 writer.close();

             } catch (final IOException e) {

                 LOG.debug("Exception during close()", e);

                 ioe = e;

             }

         }

         if (ioe != null) {

             throw ioe;

         }

     }

 }