/*
    * $Source: /usr/cvsroot/melati/melati/src/main/java/org/melati/servlet/BaseFileDataAdaptor.java,v $
    * $Revision: 1.13 $
    *
    * Copyright (C) 2000 Myles Chippendale
    *
    * Part of Melati (http://melati.org), a framework for the rapid
    * development of clean, maintainable web applications.
    *
   * Melati is free software; Permission is granted to copy, distribute
   * and/or modify this software under the terms either:
   *
   * a) the GNU General Public License as published by the Free Software
   *    Foundation; either version 2 of the License, or (at your option)
   *    any later version,
   *
   *    or
   *
   * b) any version of the Melati Software License, as published
   *    at http://melati.org
   *
   * You should have received a copy of the GNU General Public License and
   * the Melati Software License along with this program;
   * if not, write to the Free Software Foundation, Inc.,
   * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA to obtain the
   * GNU General Public License and visit http://melati.org to obtain the
   * Melati Software License.
   *
   * Feel free to contact the Developers of Melati (http://melati.org),
   * if you would like to work out a different arrangement than the options
   * outlined here.  It is our intention to allow Melati to be used by as
   * wide an audience as possible.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * Contact details for copyright holder:
   *
   *     Mylesc Chippendale <mylesc At paneris.org>
   *     http://paneris.org/
   *     29 Stanley Road, Oxford, OX4 1QY, UK
   */
  
  
  package org.melati.servlet;
  
  import java.io.OutputStream;
  import java.io.BufferedOutputStream;
  import java.io.ByteArrayOutputStream;
  import java.io.FileOutputStream;
  import java.io.BufferedInputStream;
  import java.io.FileInputStream;
  import java.io.InputStream;
  import java.io.File;
  import java.io.IOException;
  import org.melati.util.DelimitedBufferedInputStream;
  
  /**
   * Common elements of uploading a file from an HTML form.
   *
   * We store the data uploaded from a multipart form by saving it to
   * a file on disk and, optionally, give it an associated URL.
   */
  public abstract class BaseFileDataAdaptor implements FormDataAdaptor {
    /** Size for byte buffers. */
    protected int BUFSIZE = 2048;
  
    /** The file in which to save the data. */
    protected File file = null;
  
    /** A URL to the data. */
    protected String url = null;
  
    /** Information about the uploaded file. */
    public MultipartFormField field = null;
  
    /**
     * @return The file in which to save the data
     */
    protected abstract File calculateLocalFile();
  
    /**
     * Return a URL to the saved file, null if not appropriate.
     * @return a URL to the saved file, null if not appropriate
     */
    protected abstract String calculateURL();
  
  
    /**
     * Return the data in the file as a byte array.
     * @return the data in the file as a byte array
     */
    public byte[] getData() {
  
      File fileLocal = getFile();
      if (fileLocal == null)
        return new byte[0];
 
     InputStream in = null;
     ByteArrayOutputStream out = null;
     try {
       in = new BufferedInputStream(new FileInputStream(fileLocal));
       out = new ByteArrayOutputStream();
       byte[] buff = new byte[BUFSIZE];
       int count;
       while ((count = in.read(buff, 0, buff.length)) > 0)
         out.write(buff, 0, count);
       return out.toByteArray();
     }
     catch (IOException e) {
       throw new FormDataAdaptorException(
                   "Couldn't retreive the data from the file", e);
     }
     finally {
       try {
         if (in != null) {
           in.close();
           in = null;
         }
         if (out != null) {
           out.close();
           out = null;
         }
       } catch (Exception e) {
         //Cause already thrown
         e = null; // shut PMD up
       }
     }
   }
 
   /**
    * Return the size of the data.
    * @return the size of the data as a <code>long</code>
    */
   public long getSize() {
     return (getFile() != null) ? getFile().length() : 0;
   }
 
   /**
    * Return a File object pointing to the saved data.
    * 
    * @return the {@link #file}
    */
   public File getFile() {
     if (file == null)
       file = calculateLocalFile();
     return file;
   }
 
   /**
    * @return Url to the data, null if there isn't an appropriate one
    */
   public String getURL() {
     if (url == null)
       url = calculateURL();
     return url;
   }
 
   /**
    * Read data from in until the delim, work out which file to
    * save it in, and save it.
    * 
    * @param fieldP  a {@link MultipartFormField}
    * @param in     a {@link DelimitedBufferedInputStream}
    * @param delim  the delimiter used to denote elements
    * @throws IOException if there is a problem reading the input 
    */
   public void readData(MultipartFormField fieldP,
                        DelimitedBufferedInputStream in,
                        byte[] delim) throws IOException {
 
     this.field = fieldP;
     OutputStream out = null;
     byte[] buff = new byte[BUFSIZE];
     int count;
 
     try {
       // This should be the first call to get file, so hopefully we get any
       // exceptions here
       out = new BufferedOutputStream(new FileOutputStream(getFile()));
       while ((count = in.readToDelimiter(buff, 0, buff.length, delim)) > 0)
         out.write(buff, 0, count);
       if (count == -1)
         throw new IOException(
                             "Didn't find boundary whilst reading field data");
     }
     catch (IOException e) {
       throw e;
     }
     finally {
       try {
         if (out != null) {
           out.close();
           out = null;
         }
       } catch (Exception e) {
         //Cause already thrown
         e = null; // shut PMD up
       }
     }
   }
 
 
 }