JDK8/Java8源码在线阅读

/*
 * 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
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package javax.swing.plaf.metal;

import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;
import java.beans.*;
import java.io.*;
import java.util.*;
import javax.swing.plaf.*;
import javax.swing.tree.*;

import javax.swing.plaf.basic.*;

/**
 * The metal look and feel implementation of <code>TreeUI</code>.
 * <p>
 * <code>MetalTreeUI</code> allows for configuring how to
 * visually render the spacing and delineation between nodes. The following
 * hints are supported:
 *
 * <table summary="Descriptions of supported hints: Angled, Horizontal, and None">
 *  <tr>
 *    <th><p style="text-align:left">Angled</p></th>
 *    <td>A line is drawn connecting the child to the parent. For handling
 *          of the root node refer to
 *          {@link javax.swing.JTree#setRootVisible} and
 *          {@link javax.swing.JTree#setShowsRootHandles}.
 *    </td>
 *  </tr>
 *  <tr>
 *     <th><p style="text-align:left">Horizontal</p></th>
 *     <td>A horizontal line is drawn dividing the children of the root node.</td>
 *  </tr>
 *  <tr>
 *      <th><p style="text-align:left">None</p></th>
 *      <td>Do not draw any visual indication between nodes.</td>
 *  </tr>
 * </table>
 *
 * <p>
 * As it is typically impractical to obtain the <code>TreeUI</code> from
 * the <code>JTree</code> and cast to an instance of <code>MetalTreeUI</code>
 * you enable this property via the client property
 * <code>JTree.lineStyle</code>. For example, to switch to
 * <code>Horizontal</code> style you would do:
 * <code>tree.putClientProperty("JTree.lineStyle", "Horizontal");</code>
 * <p>
 * The default is <code>Angled</code>.
 *
 * @author Tom Santos
 * @author Steve Wilson (value add stuff)
 */
public class MetalTreeUI extends BasicTreeUI {

    private static Color lineColor;

    private static final String LINE_STYLE = "JTree.lineStyle";

    private static final String LEG_LINE_STYLE_STRING = "Angled";
    private static final String HORIZ_STYLE_STRING = "Horizontal";
    private static final String NO_STYLE_STRING = "None";

    private static final int LEG_LINE_STYLE = 2;
    private static final int HORIZ_LINE_STYLE = 1;
    private static final int NO_LINE_STYLE = 0;

    private int lineStyle = LEG_LINE_STYLE;
    private PropertyChangeListener lineStyleListener = new LineListener();

    // Boilerplate
    public static ComponentUI createUI(JComponent x) {
        return new MetalTreeUI();
    }

    public MetalTreeUI()
    {
        super();
    }

    protected int getHorizontalLegBuffer()
      {
          return 3;
      }

    public void installUI( JComponent c ) {
        super.installUI( c );
        lineColor = UIManager.getColor( "Tree.line" );

        Object lineStyleFlag = c.getClientProperty( LINE_STYLE );
        decodeLineStyle(lineStyleFlag);
        c.addPropertyChangeListener(lineStyleListener);

    }

    public void uninstallUI( JComponent c) {
         c.removePropertyChangeListener(lineStyleListener);
         super.uninstallUI(c);
    }

    /** this function converts between the string passed into the client property
      * and the internal representation (currently and int)
      *
      */
    protected void decodeLineStyle(Object lineStyleFlag) {
      if ( lineStyleFlag == null ||
                    lineStyleFlag.equals(LEG_LINE_STYLE_STRING)){
        lineStyle = LEG_LINE_STYLE; // default case
      } else {
          if ( lineStyleFlag.equals(NO_STYLE_STRING) ) {
              lineStyle = NO_LINE_STYLE;
          } else if ( lineStyleFlag.equals(HORIZ_STYLE_STRING) ) {
              lineStyle = HORIZ_LINE_STYLE;
          }
      }

    }

    protected boolean isLocationInExpandControl(int row, int rowLevel,
                                                int mouseX, int mouseY) {
        if(tree != null && !isLeaf(row)) {
            int                     boxWidth;

            if(getExpandedIcon() != null)
                boxWidth = getExpandedIcon().getIconWidth() + 6;
            else
                boxWidth = 8;

            Insets i = tree.getInsets();
            int    boxLeftX = (i != null) ? i.left : 0;


            boxLeftX += (((rowLevel + depthOffset - 1) * totalChildIndent) +
                        getLeftChildIndent()) - boxWidth/2;

            int boxRightX = boxLeftX + boxWidth;

            return mouseX >= boxLeftX && mouseX <= boxRightX;
        }
        return false;
    }

    public void paint(Graphics g, JComponent c) {
        super.paint( g, c );


        // Paint the lines
        if (lineStyle == HORIZ_LINE_STYLE && !largeModel) {
            paintHorizontalSeparators(g,c);
        }
    }

    protected void paintHorizontalSeparators(Graphics g, JComponent c) {
        g.setColor( lineColor );

        Rectangle clipBounds = g.getClipBounds();

        int beginRow = getRowForPath(tree, getClosestPathForLocation
                                     (tree, 0, clipBounds.y));
        int endRow = getRowForPath(tree, getClosestPathForLocation
                             (tree, 0, clipBounds.y + clipBounds.height - 1));

        if ( beginRow <= -1 || endRow <= -1 ) {
            return;
        }

        for ( int i = beginRow; i <= endRow; ++i ) {
            TreePath        path = getPathForRow(tree, i);

            if(path != null && path.getPathCount() == 2) {
                Rectangle       rowBounds = getPathBounds(tree,getPathForRow
                                                          (tree, i));

                // Draw a line at the top
                if(rowBounds != null)
                    g.drawLine(clipBounds.x, rowBounds.y,
                               clipBounds.x + clipBounds.width, rowBounds.y);
            }
        }

    }

    protected void paintVerticalPartOfLeg(Graphics g, Rectangle clipBounds,
                                          Insets insets, TreePath path) {
        if (lineStyle == LEG_LINE_STYLE) {
            super.paintVerticalPartOfLeg(g, clipBounds, insets, path);
        }
    }

    protected void paintHorizontalPartOfLeg(Graphics g, Rectangle clipBounds,
                                            Insets insets, Rectangle bounds,
                                            TreePath path, int row,

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