tempfilemanager.java

一个用java写的mail.里面的代码值得我们去研究！学习。

/*
** $Id: TempFileManager.java,v 1.3 2001/05/07 12:37:22 kunugi Exp $
**
** Copyright (c) 2000-2001 Jeff Gay
** on behalf of ICEMail.org <http://www.icemail.org>
** Copyright (c) 1998-2000 by Timothy Gerard Endres
** 
** This program is free software.
** 
** You may redistribute it and/or modify it under the terms of the GNU
** General Public License as published by the Free Software Foundation.
** Version 2 of the license should be included with this distribution in
** the file LICENSE, as well as License.html. If the license is not
** included with this distribution, you may find a copy at the FSF web
** site at 'www.gnu.org' or 'www.fsf.org', or you may write to the
** Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139 USA.
**
** THIS SOFTWARE IS PROVIDED AS-IS WITHOUT WARRANTY OF ANY KIND,
** NOT EVEN THE IMPLIED WARRANTY OF MERCHANTABILITY. THE AUTHOR
** OF THIS SOFTWARE, ASSUMES _NO_ RESPONSIBILITY FOR ANY
** CONSEQUENCE RESULTING FROM THE USE, MODIFICATION, OR
** REDISTRIBUTION OF THIS SOFTWARE. 
*/

package org.icemail.mail;

import java.io.File;

import java.util.Vector;


/**
 * A class to manage temporary files by name,
 * allowing temporary file names to be produced in a sequenced fasion,
 * as well as the deletion of all temporary files created.
 */
public class TempFileManager
{
  private String    prefix_ = null;
  private String    suffix_ = null;
  private String    directory_ = null;

  private int       lastId_ = 0;
  private Vector    fileNames_ = new Vector();

  /**
   * Create a temporary file manager which will produce file names with
   * using the given prefix and suffix.
   * <p>
   * File names have the following structure: [prefix]##[suffix] where the
   * ## is the id of the file name.
   * <p>
   * The directory must be set before using the temporary file manager by
   * calling setDirectory() below.
   */
  public
  TempFileManager( String prefix, String suffix ) {
    prefix_ = prefix;
    suffix_ = suffix;
  }

// accessors

  /**
   * Get the prefix used when constructing file names.
   *
   * @return the prefix used when constructing file names
   */
  public String
  getPrefix() {
    return prefix_;
  }

  /**
   * Get the suffix used when constructing file names.
   *
   * @return the suffix used when constructing file names
   */
  public String
  getSuffix() {
    return suffix_;
  }

  /**
   * Get the current directory used when creating temporary files.
   *
   * @return the current directory used when creating temporary files.
   */
  public String
  getDirectory() {
    return directory_;
  }

  /**
   * Get the number of temporary file names constructed, which may or
   * may not be the number of actual temporary files created.
   *
   * @return the number of temporary file names constructed
   */
  public int
  getNumberOfFiles() {
    return fileNames_.size();
  }

// mutators

  /**
   * Set the directory to be used when creating temporary files.
   *
   * @param directory the directory to be used when creating temporary files
   */
  public void
  setDirectory( String directory ) {
    directory_ = directory;
  }

// helpers

  /**
   * Get a temporary file name.
   * The file name is created from the manager's prefix and given suffix.
   * If the given suffix is null then the manager's suffix is used.
   *
   * @param suffix the given suffix of the file name or null
   */
  public String
  getFilename( String suffix ) {
  // use the default suffix if necessary
    if ( suffix == null ) {
      suffix = suffix_;
    }

  // create a temporary file name
    String xfilename = directory_ + File.separator + prefix_ + "-" + lastId_ + suffix;

    lastId_++;

    fileNames_.addElement( xfilename );

    return xfilename;
  }

  /**
   * Delete all temporary files by name.
   * The list of names maintained by the manager is used to delete any
   * temporary files created.
   */
  public void
  deleteAllFiles() {
    int count = 0;
    int numFiles = fileNames_.size();

    for ( int idx = 0 ; idx < numFiles ; idx++ ) {
      String fileName = (String)fileNames_.elementAt( idx );

      File f = new File( fileName );

      if ( f.exists() && f.isFile() ) {
        f.delete();
        count++;
      }
    }

    System.err.println( "Deleted " + count + " temporary documents." );
  }

  /**
   * Returns a string representation of the object.
   * <p>
   * Implements Object.toString()
   *
   * @return a string representation of the object
   */
  public String
  toString() {
    return "TempFileManager: p-" + prefix_ + ", s-" + suffix_ + ", d-" + directory_;
  }

}