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Java example source code file (Util.java)

This example Java source code file (Util.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

arraylist, awt, bufferedimage, callable, component, container, event, exception, filling, gui, image, integer, interruptedexception, oome, override, point, problem, string, swing, util

The Util.java Java example source code

/*
 * Copyright (c) 2011, 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.
 *
 * 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.
 */

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.concurrent.Callable;
import sun.swing.*;

/**
 * <p>This class contains utilities useful for regression testing.
 * <p>When using jtreg you would include this class via something like:
 * <pre>
 *
 * @library ../../regtesthelpers
 * @build Util
 * </pre>
 */

public class Util {
    /**
     * Convert a rectangle from coordinate system of Component c to
     * screen coordinate system.
     *
     * @param r a non-null Rectangle
     * @param c a Component whose coordinate system is used for conversion
     */
    public static void convertRectToScreen(Rectangle r, Component c) {
        Point p = new Point(r.x, r.y);
        SwingUtilities.convertPointToScreen(p, c);
        r.x = p.x;
        r.y = p.y;
    }

    /**
     * Compares two bufferedImages pixel-by-pixel.
     * return true if all pixels in the two areas are identical
     */
    public static boolean compareBufferedImages(BufferedImage bufferedImage0, BufferedImage bufferedImage1) {
        int width = bufferedImage0.getWidth();
        int height = bufferedImage0.getHeight();

        if (width != bufferedImage1.getWidth() || height != bufferedImage1.getHeight()) {
            return false;
        }

        for (int y = 0; y < height; y++) {
            for (int x = 0; x < width; x++) {
                if (bufferedImage0.getRGB(x, y) != bufferedImage1.getRGB(x, y)) {
                    return false;
                }
            }
        }

        return true;
    }

    /**
     * Fills the heap until OutOfMemoryError occurs. This method is useful for
     * WeakReferences removing.
     */
    public static void generateOOME() {
        List<Object> bigLeak = new LinkedList();

        boolean oome = false;

        System.out.print("Filling the heap");

        try {
            for(int i = 0; true ; i++) {
                // Now, use up all RAM
                bigLeak.add(new byte[1024 * 1024]);

                System.out.print(".");

                // Give the GC a change at that weakref
                if (i % 10 == 0) {
                    System.gc();
                    try {
                        Thread.sleep(100);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        } catch (OutOfMemoryError e) {
            bigLeak = null;
            oome = true;
        }

        System.out.println("");

        if (!oome) {
            throw new RuntimeException("Problem with test case - never got OOME");
        }

        System.out.println("Got OOME");
    }

    /**
     * Find a sub component by class name.
     * Always run this method on the EDT thread
     */
    public static Component findSubComponent(Component parent, String className) {
        String parentClassName = parent.getClass().getName();

        if (parentClassName.contains(className)) {
            return parent;
        }

        if (parent instanceof Container) {
            for (Component child : ((Container) parent).getComponents()) {
                Component subComponent = findSubComponent(child, className);

                if (subComponent != null) {
                    return subComponent;
                }
            }
        }

        return null;
    }

     /**
     * Hits mnemonics by robot.
     */
    public static void hitMnemonics(Robot robot, int... keys) {

        ArrayList<Integer> mnemonicKeyCodes = getSystemMnemonicKeyCodes();
        for (Integer mnemonic : mnemonicKeyCodes) {
            robot.keyPress(mnemonic);
        }

        hitKeys(robot, keys);

        for (Integer mnemonic : mnemonicKeyCodes) {
            robot.keyRelease(mnemonic);
        }
    }

     /**
     * Hits keys by robot.
     */
    public static void hitKeys(Robot robot, int... keys) {
        for (int i = 0; i < keys.length; i++) {
            robot.keyPress(keys[i]);
        }

        for (int i = keys.length - 1; i >= 0; i--) {
            robot.keyRelease(keys[i]);
        }
    }

    /**
     * Moves mouse smoothly from (x0, y0) to (x1, y1).
     */
    public static void glide(Robot robot, int x0, int y0, int x1, int y1) throws AWTException {
        float dmax = (float) Math.max(Math.abs(x1 - x0), Math.abs(y1 - y0));
        float dx = (x1 - x0) / dmax;
        float dy = (y1 - y0) / dmax;

        for (int i = 0; i <= dmax; i += 10) {
            robot.mouseMove((int) (x0 + dx * i), (int) (y0 + dy * i));
        }
    }

    /**
     * Gets component center point
     *
     * @return center point of the <code>component
     */
    public static Point getCenterPoint(final Component component) throws Exception {
        return Util.invokeOnEDT(new Callable<Point>() {

            @Override
            public Point call() throws Exception {
                Point p = component.getLocationOnScreen();
                Dimension size = component.getSize();
                return new Point(p.x + size.width / 2, p.y + size.height / 2);
            }
        });
    }

    /**
     * Invokes the <code>task on the EDT thread.
     *
     * @return result of the <code>task
     */
    public static <T> T invokeOnEDT(final Callable task) throws Exception {
        final List<T> result = new ArrayList<>(1);
        final Exception[] exception = new Exception[1];

        SwingUtilities.invokeAndWait(new Runnable() {
            @Override
            public void run() {
                try {
                    result.add(task.call());
                } catch (Exception e) {
                    exception[0] = e;
                }
            }
        });

        if (exception[0] != null) {
            throw exception[0];
        }

        return result.get(0);
    }
    /**
     * Gets key codes from system mnemonic key mask
     * @return key codes list
     */
    public static ArrayList<Integer> getSystemMnemonicKeyCodes() {
        return Util.getKeyCodesFromKeyMask(SwingUtilities2.getSystemMnemonicKeyMask());
    }

    /**
     * Gets the key codes list from modifiers
     * @param modifiers an integer combination of the modifier constants
     * @return key codes list
     */
    public static ArrayList<Integer> getKeyCodesFromKeyMask(int modifiers) {
        ArrayList<Integer> result = new ArrayList<>();
        if ((modifiers & InputEvent.CTRL_MASK) != 0) {
            result.add(KeyEvent.VK_CONTROL);
        }
        if ((modifiers & InputEvent.ALT_MASK) != 0) {
            result.add(KeyEvent.VK_ALT);
        }
        if ((modifiers & InputEvent.SHIFT_MASK) != 0) {
            result.add(KeyEvent.VK_SHIFT);
        }
        if ((modifiers & InputEvent.META_MASK) != 0) {
            result.add(KeyEvent.VK_META);
        }
        return result;
    }
}




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