Java example source code file (AbstractLayoutCache.java)

This example Java source code file (AbstractLayoutCache.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

abstractlayoutcache, awt, enumeration, event, gui, nodedimensions, rectangle, rowmapper, swing, treemodel, treepath, treeselectionmodel, util

The AbstractLayoutCache.java Java example source code

/*
 * Copyright (c) 1998, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package javax.swing.tree;

import javax.swing.event.TreeModelEvent;
import java.awt.Dimension;
import java.awt.Rectangle;
import java.util.Enumeration;

/**
 * <strong>Warning:
 * Serialized objects of this class will not be compatible with
 * future Swing releases. The current serialization support is
 * appropriate for short term storage or RMI between applications running
 * the same version of Swing.  As of 1.4, support for long term storage
 * of all JavaBeans™
 * has been added to the <code>java.beans package.
 * Please see {@link java.beans.XMLEncoder}.
 *
 * @author Scott Violet
 */

public abstract class AbstractLayoutCache implements RowMapper {
    /** Object responsible for getting the size of a node. */
    protected NodeDimensions     nodeDimensions;

    /** Model providing information. */
    protected TreeModel          treeModel;

    /** Selection model. */
    protected TreeSelectionModel treeSelectionModel;

    /**
     * True if the root node is displayed, false if its children are
     * the highest visible nodes.
     */
    protected boolean            rootVisible;

    /**
      * Height to use for each row.  If this is <= 0 the renderer will be
      * used to determine the height for each row.
      */
    protected int                rowHeight;


    /**
     * Sets the renderer that is responsible for drawing nodes in the tree
     * and which is therefore responsible for calculating the dimensions of
     * individual nodes.
     *
     * @param nd a <code>NodeDimensions object
     */
    public void setNodeDimensions(NodeDimensions nd) {
        this.nodeDimensions = nd;
    }

    /**
     * Returns the object that renders nodes in the tree, and which is
     * responsible for calculating the dimensions of individual nodes.
     *
     * @return the <code>NodeDimensions object
     */
    public NodeDimensions getNodeDimensions() {
        return nodeDimensions;
    }

    /**
     * Sets the <code>TreeModel that will provide the data.
     *
     * @param newModel the <code>TreeModel that is to
     *          provide the data
     */
    public void setModel(TreeModel newModel) {
        treeModel = newModel;
    }

    /**
     * Returns the <code>TreeModel that is providing the data.
     *
     * @return the <code>TreeModel that is providing the data
     */
    public TreeModel getModel() {
        return treeModel;
    }

    /**
     * Determines whether or not the root node from
     * the <code>TreeModel is visible.
     *
     * @param rootVisible true if the root node of the tree is to be displayed
     * @see #rootVisible
     * @beaninfo
     *        bound: true
     *  description: Whether or not the root node
     *               from the TreeModel is visible.
     */
    public void setRootVisible(boolean rootVisible) {
        this.rootVisible = rootVisible;
    }

    /**
     * Returns true if the root node of the tree is displayed.
     *
     * @return true if the root node of the tree is displayed
     * @see #rootVisible
     */
    public boolean isRootVisible() {
        return rootVisible;
    }

    /**
     * Sets the height of each cell.  If the specified value
     * is less than or equal to zero the current cell renderer is
     * queried for each row's height.
     *
     * @param rowHeight the height of each cell, in pixels
     * @beaninfo
     *        bound: true
     *  description: The height of each cell.
     */
    public void setRowHeight(int rowHeight) {
        this.rowHeight = rowHeight;
    }

    /**
     * Returns the height of each row.  If the returned value is less than
     * or equal to 0 the height for each row is determined by the
     * renderer.
     */
    public int getRowHeight() {
        return rowHeight;
    }

    /**
     * Sets the <code>TreeSelectionModel used to manage the
     * selection to new LSM.
     *
     * @param newLSM  the new <code>TreeSelectionModel
     */
    public void setSelectionModel(TreeSelectionModel newLSM) {
        if(treeSelectionModel != null)
            treeSelectionModel.setRowMapper(null);
        treeSelectionModel = newLSM;
        if(treeSelectionModel != null)
            treeSelectionModel.setRowMapper(this);
    }

    /**
     * Returns the model used to maintain the selection.
     *
     * @return the <code>treeSelectionModel
     */
    public TreeSelectionModel getSelectionModel() {
        return treeSelectionModel;
    }

    /**
     * Returns the preferred height.
     *
     * @return the preferred height
     */
    public int getPreferredHeight() {
        // Get the height
        int           rowCount = getRowCount();

        if(rowCount > 0) {
            Rectangle     bounds = getBounds(getPathForRow(rowCount - 1),
                                             null);

            if(bounds != null)
                return bounds.y + bounds.height;
        }
        return 0;
    }

    /**
     * Returns the preferred width for the passed in region.
     * The region is defined by the path closest to
     * <code>(bounds.x, bounds.y) and
     * ends at <code>bounds.height + bounds.y.
     * If <code>bounds is null,
     * the preferred width for all the nodes
     * will be returned (and this may be a VERY expensive
     * computation).
     *
     * @param bounds the region being queried
     * @return the preferred width for the passed in region
     */
    public int getPreferredWidth(Rectangle bounds) {
        int           rowCount = getRowCount();

        if(rowCount > 0) {
            // Get the width
            TreePath      firstPath;
            int           endY;

            if(bounds == null) {
                firstPath = getPathForRow(0);
                endY = Integer.MAX_VALUE;
            }
            else {
                firstPath = getPathClosestTo(bounds.x, bounds.y);
                endY = bounds.height + bounds.y;
            }

            Enumeration   paths = getVisiblePathsFrom(firstPath);

            if(paths != null && paths.hasMoreElements()) {
                Rectangle   pBounds = getBounds((TreePath)paths.nextElement(),
                                                null);
                int         width;

                if(pBounds != null) {
                    width = pBounds.x + pBounds.width;
                    if (pBounds.y >= endY) {
                        return width;
                    }
                }
                else
                    width = 0;
                while (pBounds != null && paths.hasMoreElements()) {
                    pBounds = getBounds((TreePath)paths.nextElement(),
                                        pBounds);
                    if (pBounds != null && pBounds.y < endY) {
                        width = Math.max(width, pBounds.x + pBounds.width);
                    }
                    else {
                        pBounds = null;
                    }
                }
                return width;
            }
        }
        return 0;
    }

    //
    // Abstract methods that must be implemented to be concrete.
    //

    /**
      * Returns true if the value identified by row is currently expanded.
      */
    public abstract boolean isExpanded(TreePath path);

    /**
     * Returns a rectangle giving the bounds needed to draw path.
     *
     * @param path     a <code>TreePath specifying a node
     * @param placeIn  a <code>Rectangle object giving the
     *          available space
     * @return a <code>Rectangle object specifying the space to be used
     */
    public abstract Rectangle getBounds(TreePath path, Rectangle placeIn);

    /**
      * Returns the path for passed in row.  If row is not visible
      * <code>null is returned.
      *
      * @param row  the row being queried
      * @return the <code>TreePath for the given row
      */
    public abstract TreePath getPathForRow(int row);

    /**
      * Returns the row that the last item identified in path is visible
      * at.  Will return -1 if any of the elements in path are not
      * currently visible.
      *
      * @param path the <code>TreePath being queried
      * @return the row where the last item in path is visible or -1
      *         if any elements in path aren't currently visible
      */
    public abstract int getRowForPath(TreePath path);

    /**
      * Returns the path to the node that is closest to x,y.  If
      * there is nothing currently visible this will return <code>null,
      * otherwise it'll always return a valid path.
      * If you need to test if the
      * returned object is exactly at x, y you should get the bounds for
      * the returned path and test x, y against that.
      *
      * @param x the horizontal component of the desired location
      * @param y the vertical component of the desired location
      * @return the <code>TreePath closest to the specified point
      */
    public abstract TreePath getPathClosestTo(int x, int y);

    /**
     * Returns an <code>Enumerator that increments over the visible
     * paths starting at the passed in location. The ordering of the
     * enumeration is based on how the paths are displayed.
     * The first element of the returned enumeration will be path,
     * unless it isn't visible,
     * in which case <code>null will be returned.
     *
     * @param path the starting location for the enumeration
     * @return the <code>Enumerator starting at the desired location
     */
    public abstract Enumeration<TreePath> getVisiblePathsFrom(TreePath path);

    /**
     * Returns the number of visible children for row.
     *
     * @param path  the path being queried
     * @return the number of visible children for the specified path
     */
    public abstract int getVisibleChildCount(TreePath path);

    /**
     * Marks the path <code>path expanded state to
     * <code>isExpanded.
     *
     * @param path  the path being expanded or collapsed
     * @param isExpanded true if the path should be expanded, false otherwise
     */
    public abstract void setExpandedState(TreePath path, boolean isExpanded);

    /**
     * Returns true if the path is expanded, and visible.
     *
     * @param path  the path being queried
     * @return true if the path is expanded and visible, false otherwise
     */
    public abstract boolean getExpandedState(TreePath path);

    /**
     * Number of rows being displayed.
     *
     * @return the number of rows being displayed
     */
    public abstract int getRowCount();

    /**
     * Informs the <code>TreeState that it needs to recalculate
     * all the sizes it is referencing.
     */
    public abstract void invalidateSizes();

    /**
     * Instructs the <code>LayoutCache that the bounds for
     * <code>path are invalid, and need to be updated.
     *
     * @param path the path being updated
     */
    public abstract void invalidatePathBounds(TreePath path);

    //
    // TreeModelListener methods
    // AbstractTreeState does not directly become a TreeModelListener on
    // the model, it is up to some other object to forward these methods.
    //

    /**
     * <p>
     * Invoked after a node (or a set of siblings) has changed in some
     * way. The node(s) have not changed locations in the tree or
     * altered their children arrays, but other attributes have
     * changed and may affect presentation. Example: the name of a
     * file has changed, but it is in the same location in the file
     * system.</p>
     *
     * <p>e.path() returns the path the parent of the changed node(s).

     *
     * <p>e.childIndices() returns the index(es) of the changed node(s).

     *
     * @param e  the <code>TreeModelEvent
     */
    public abstract void treeNodesChanged(TreeModelEvent e);

    /**
     * <p>Invoked after nodes have been inserted into the tree.

     *
     * <p>e.path() returns the parent of the new nodes

     * <p>e.childIndices() returns the indices of the new nodes in
     * ascending order.</p>
     *
     * @param e the <code>TreeModelEvent
     */
    public abstract void treeNodesInserted(TreeModelEvent e);

    /**
     * <p>Invoked after nodes have been removed from the tree.  Note that
     * if a subtree is removed from the tree, this method may only be
     * invoked once for the root of the removed subtree, not once for
     * each individual set of siblings removed.</p>
     *
     * <p>e.path() returns the former parent of the deleted nodes.

     *
     * <p>e.childIndices() returns the indices the nodes had before they were deleted in ascending order.

     *
     * @param e the <code>TreeModelEvent
     */
    public abstract void treeNodesRemoved(TreeModelEvent e);

    /**
     * <p>Invoked after the tree has drastically changed structure from a
     * given node down.  If the path returned by <code>e.getPath()
     * is of length one and the first element does not identify the
     * current root node the first element should become the new root
     * of the tree.</p>
     *
     * <p>e.path() holds the path to the node.

     * <p>e.childIndices() returns null.

     *
     * @param e the <code>TreeModelEvent
     */
    public abstract void treeStructureChanged(TreeModelEvent e);

    //
    // RowMapper
    //

    /**
     * Returns the rows that the <code>TreePath instances in
     * <code>path are being displayed at.
     * This method should return an array of the same length as that passed
     * in, and if one of the <code>TreePaths
     * in <code>path is not valid its entry in the array should
     * be set to -1.
     *
     * @param paths the array of <code>TreePaths being queried
     * @return an array of the same length that is passed in containing
     *          the rows that each corresponding where each
     *          <code>TreePath is displayed; if paths
     *          is <code>null, null is returned
     */
    public int[] getRowsForPaths(TreePath[] paths) {
        if(paths == null)
            return null;

        int               numPaths = paths.length;
        int[]             rows = new int[numPaths];

        for(int counter = 0; counter < numPaths; counter++)
            rows[counter] = getRowForPath(paths[counter]);
        return rows;
    }

    //
    // Local methods that subclassers may wish to use that are primarly
    // convenience methods.
    //

    /**
     * Returns, by reference in <code>placeIn,
     * the size needed to represent <code>value.
     * If <code>inPlace is null, a newly created
     * <code>Rectangle should be returned, otherwise the value
     * should be placed in <code>inPlace and returned. This will
     * return <code>null if there is no renderer.
     *
     * @param value the <code>value to be represented
     * @param row  row being queried
     * @param depth the depth of the row
     * @param expanded true if row is expanded, false otherwise
     * @param placeIn  a <code>Rectangle containing the size needed
     *          to represent <code>value
     * @return a <code>Rectangle containing the node dimensions,
     *          or <code>null if node has no dimension
     */
    protected Rectangle getNodeDimensions(Object value, int row, int depth,
                                          boolean expanded,
                                          Rectangle placeIn) {
        NodeDimensions            nd = getNodeDimensions();

        if(nd != null) {
            return nd.getNodeDimensions(value, row, depth, expanded, placeIn);
        }
        return null;
    }

    /**
      * Returns true if the height of each row is a fixed size.
      */
    protected boolean isFixedRowHeight() {
        return (rowHeight > 0);
    }


    /**
     * Used by <code>AbstractLayoutCache to determine the size
     * and x origin of a particular node.
     */
    static public abstract class NodeDimensions {
        /**
         * Returns, by reference in bounds, the size and x origin to
         * place value at. The calling method is responsible for determining
         * the Y location. If bounds is <code>null, a newly created
         * <code>Rectangle should be returned,
         * otherwise the value should be placed in bounds and returned.
         *
         * @param value the <code>value to be represented
         * @param row row being queried
         * @param depth the depth of the row
         * @param expanded true if row is expanded, false otherwise
         * @param bounds  a <code>Rectangle containing the size needed
         *              to represent <code>value
         * @return a <code>Rectangle containing the node dimensions,
         *              or <code>null if node has no dimension
         */
        public abstract Rectangle getNodeDimensions(Object value, int row,
                                                    int depth,
                                                    boolean expanded,
                                                    Rectangle bounds);
    }
}