foldertreenode.java

来自「一个用java写的mail.里面的代码值得我们去研究！学习。」· Java 代码 · 共 173 行

/*
** $Id: FolderTreeNode.java,v 1.3 2001/05/07 12:37:21 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 javax.mail.Store;
import javax.mail.Folder;
import javax.mail.MessagingException;

import javax.swing.tree.DefaultMutableTreeNode;


/**
 * The class represents a Folder and all related messages and sub-folders as nodes on a tree.
 *
 * @see FolderTreePanel
 */
public class FolderTreeNode
  extends DefaultMutableTreeNode
{
  private Folder  folder = null;
  private boolean hasLoaded = false;
  private boolean haveLeaf = false;
  private boolean cachedLeaf = false;

  /**
   * Construct a tree node that references the given folder.
   *
   * @param folder the folder for this node
   */
  public
  FolderTreeNode( Folder folder ) {
    super( folder );
    this.folder = folder;
  }

  /**
   * Get the underlying folder of this node.
   *
   * @return the underlying folder of this node.
   */
  public Folder
  getFolder() {
    return this.folder;
  }

  /**
   * Return the folder's name rather than the full path.
   *
   * @return the folder's name rather than the full path.
   */
  public String
  toString() {
    return folder.getName();
  }

//............................................................

  /**
   * Returns a shallow copy of this node; the new node has no parent
   * or children and has a reference to the same user object, if any.
   * <p>
   * Implementation of java.swing.tree.DefaultMutableTreeNode.clone()
   *
   * @return a copy of this node
   */
  public Object
  clone() {
    FolderTreeNode newNode = (FolderTreeNode) super.clone();

    newNode.folder = folder;
    newNode.hasLoaded = hasLoaded;
    newNode.haveLeaf = haveLeaf;
    newNode.cachedLeaf = cachedLeaf;

    return newNode;
  }

  /**
   * Returns true if this node has no children.
   * A Folder is a leaf if it does not contain sub-folders.
   * <p>
   * Implementation of java.swing.tree.DefaultMutableTreeNode.isLeaf()
   *
   * @return true if the folder contains sub-folders
   */
  public boolean
  isLeaf() {
    if ( ! this.haveLeaf ) {
      try {
        MailUtilities.setStoreConnected( folder.getStore() );
        int type = folder.getType();
        this.cachedLeaf = ( ( type & Folder.HOLDS_FOLDERS ) == 0 );
        this.haveLeaf = true;
      } catch ( MessagingException ex ) {
      }
    }
    return this.cachedLeaf;
  }

  /**
   * Returns the number of children of this node.
   * <p>
   * The first time this method is called, all sub-folders are added.
   * <p>
   * Implementation of java.swing.tree.DefaultMutableTreeNode.getChildCount()
   *
   * @return the number of children of this node
   */
  public int
  getChildCount() {
    if ( ! this.hasLoaded ) {
      this.loadChildren();
    }
    return super.getChildCount();
  }

//............................................................

  private void
  loadChildren() {
  // if it is a leaf, just say we have loaded them
    if ( this.isLeaf() ) {
      this.hasLoaded = true;
      return;
    }

    try {
      Folder[] sub = folder.list();

      if ( sub.length > 1 ) {
        RootTreeNode.sortFolderList( sub );
      }

    // add a FolderTreeNode for each Folder
      int num = sub.length;
      for( int i = 0 ; i < num ; i++ ) {
        FolderTreeNode node = new FolderTreeNode( sub[i] );

      // We use insert here, since add() would make
      // another recursive call to getChildCount();
        this.insert( node, i );
      }

      this.hasLoaded = true;
    } catch ( MessagingException ex ) {
      ex.printStackTrace();
    }
  }

}