/*

  * Copyright 1999-2001,2004 The Apache Software 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.

  */ 

 package org.apache.commons.workflow.io;

 import java.io.BufferedInputStream;

 import java.io.FileInputStream;

 import java.io.InputStreamReader;

 import java.io.IOException;

 import org.apache.commons.workflow.Context;

 import org.apache.commons.workflow.StepException;

 import org.apache.commons.workflow.base.BaseStep;

 /**

  * <p>Read the contents of the specified file from the filesystem, and

  * push the contents as a String object onto the evaluation stack.</p>

  *

  * <p>Supported Attributes:</p>

  * <ul>

  * <li><strong>encoding</strong> - Character encoding in which to interpret

  *     the characters in the specified file, or omitted for the platform

  *     default encoding.</li>

  * <li><strong>file</strong> - Relative or absolute operating system pathname

  *     whose contents are to be read.</li>

  * </ul>

  *

  * <strong>DESIGN QUESTION - What about binary content?</strong>

  *

  * @version $Revision: 155475 $ $Date: 2005-02-26 13:31:11 +0000 (Sat, 26 Feb 2005) $

  * @author Craig R. McClanahan

  */

 public class ReadStep extends BaseStep {

     // ----------------------------------------------------------= Constructors

     /**

      * Construct a default instance of this Step.

      */

     public ReadStep() {

         super();

     }

     /**

      * Construct an instance of this Step with the specified identifier.

      *

      * @param id Step identifier

      */

     public ReadStep(String id) {

         super();

         setId(id);

     }

     /**

      * Construct a fully configured instance of this Step.

      *

      * @param id Step identifier

      * @param encoding Character encoding to use

      * @param file Relative or absolute pathname

      */

     public ReadStep(String id, String encoding, String file) {

         super();

         setId(id);

         setEncoding(encoding);

         setFile(file);

     }

     // ------------------------------------------------------------- Properties

     /**

      * The character encoding used to interpret the contents of this file.

      */

     protected String encoding = null;

     public String getEncoding() {

         return (this.encoding);

     }

     public void setEncoding(String encoding) {

         this.encoding = encoding;

     }

     /**

      * The relative or absolute pathname of the operating system file.

      */

     protected String file = null;

     public String getFile() {

         return (this.file);

     }

     public void setFile(String file) {

         this.file = file;

     }

     // --------------------------------------------------------- Public Methods

     /**

      * Perform the executable actions related to this Step, in the context of

      * the specified Context.

      *

      * @param context The Context that is tracking our execution state

      *

      * @exception StepException if a processing error has occurred

      */

     public void execute(Context context) throws StepException {

         // Define variables we will need later

         FileInputStream fis = null;

         BufferedInputStream bis = null;

         InputStreamReader isr = null;

         StringBuffer sb = new StringBuffer();

         StepException se = null;

         try {

             // Construct a suitable InputStreamReader

             fis = new FileInputStream(file);

             bis = new BufferedInputStream(fis, 2048);

             if (encoding == null)

                 isr = new InputStreamReader(bis);

             else

                 isr = new InputStreamReader(bis, encoding);

             // Copy all characters from this file

             while (true) {

                 int ch = isr.read();

                 if (ch < 0)

                     break;

                 sb.append((char) ch);

             }

             // Close the input file

             isr.close();

             isr = null;

             bis = null;

             fis = null;

         } catch (IOException e) {

             se = new StepException("IOException processing '" + file + "'",

                                    e, this);

         } finally {

             if (isr != null) {

                 try {

                     isr.close();

                 } catch (Throwable t) {

                     ;

                 }

             } else if (bis != null) {

                 try {

                     bis.close();

                 } catch (Throwable t) {

                     ;

                 }

             } else if (fis != null) {

                 try {

                     fis.close();

                 } catch (Throwable t) {

                     ;

                 }

             }

         }

         // Push results or throw exception as appropriate

         if (se != null)

             throw se;

         context.push(sb.toString());

     }

 }