dynamictreenode.java

编辑视频文件

/*
 * File:     DynamicTreeNode.java
 * Project:  MPI Linguistic Application
 * Date:     02 May 2007
 *
 * Copyright (C) 2001-2007  Max Planck Institute for Psycholinguistics
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of 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.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package mpi.eudico.server.corpora.clom;

import java.util.Iterator;
import java.util.Vector;

import javax.swing.tree.DefaultMutableTreeNode;


/**
 * A Node to be used in a JTree that loads its contents dynamicaly. This has
 * the advantage that the nodes only will be added to the  JTree when they are
 * needed. If the EUDICO data tree would be loaded staticaly we would have to
 * add all the Transcriptions from all the (Sub)Corpora to the Tree before
 * showing it to the user.
 *
 * @author Hennie Brugman
 * @author Albert Russel
 * @version 06-Mai-1998
 * @version Aug 2005 Identity removed
 */
public class DynamicTreeNode extends DefaultMutableTreeNode {
    /** The Object that is the content of this TreeNode. */
    private TreeViewable nodeObject;

    /**
     * A flag that indicates whether this nodes child nodes are loaded. Since
     * this is a DynamicTreeNode the default value is false.
     */
    private boolean childrenLoaded;

    /**
     * Creates a DynamicTreeNode with theNodeObject as its content and
     * depending on Identity zero or more available child nodes. When a user
     * has for example no acces to Transcription X in a certain Corpus Y that
     * Transcription X will not be returned if that user askes for the child
     * nodes that belong to Corpus Y.
     *
     * @param theNodeObject The Object that becomes the content of this node.
     *        Not Nullable.
     *
     * @throws RuntimeException DOCUMENT ME!
     */
    public DynamicTreeNode(TreeViewable theNodeObject) {
        super(theNodeObject);

        if (theNodeObject == null) {
            throw new RuntimeException(
                "DynamicTreeNode: given NodeObject is null");
        }

        nodeObject = theNodeObject;
        childrenLoaded = false;
    }

    /**
     * Returns the String with which the node Object is visible in the JTree.
     *
     * @return DOCUMENT ME!
     */
    public String toString() {
        return nodeObject.getNodeName();
    }

    /**
     * Returns false if this node has children, otherwise true.
     *
     * @return DOCUMENT ME!
     */
    public boolean isTreeViewableLeaf() {
        return nodeObject.isTreeViewableLeaf();
    }

    /**
     * Is called when the tree wants to know how many children a node has.
     * therefore this is the moment to load a nodes children if they where not
     * already loaded.
     *
     * @return DOCUMENT ME!
     */
    public int getChildCount() {
        if (!childrenLoaded) {
            loadChildren();
        }

        return super.getChildCount();
    }

    /**
     * Loads all the child nodes from this DynamicTreeNode that are available
     * for identity and inserts them into the JTree.
     * <pre>
     *     Precondition: none of the children of the node is NULL
     *     (Errorcase) for each child of the node that is NULL: skip and log.
     *     </pre>
     */
    private void loadChildren() {
        int i = 0;
        DynamicTreeNode newNode;
        Vector children = nodeObject.getChildren();
        Iterator iter = children.iterator();

        while (iter.hasNext()) {
            TreeViewable node = (TreeViewable) iter.next();

            if (node == null) {
                System.err.println(
                    "DynamicTreeNode: skipping a NULL Node child.");
            } else {
                newNode = new DynamicTreeNode(node);
                insert(newNode, i++);
            }
        }

        childrenLoaded = true;
    }
}