Java tutorial
/* * Copyright (c) 1997, 2018, 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; import java.awt.*; import java.util.*; import java.awt.event.*; import javax.swing.event.*; import sun.awt.AppContext; import sun.awt.AWTAccessor; import sun.awt.AWTAccessor.MouseEventAccessor; import sun.swing.SwingUtilities2; /** * A MenuSelectionManager owns the selection in menu hierarchy. * * @author Arnaud Weber * @since 1.2 */ public class MenuSelectionManager { private Vector<MenuElement> selection = new Vector<MenuElement>(); /* diagnostic aids -- should be false for production builds. */ private static final boolean TRACE = false; // trace creates and disposes private static final boolean VERBOSE = false; // show reuse hits/misses private static final boolean DEBUG = false; // show bad params, misc. private static final StringBuilder MENU_SELECTION_MANAGER_KEY = new StringBuilder( "javax.swing.MenuSelectionManager"); /** * Returns the default menu selection manager. * * @return a MenuSelectionManager object */ public static MenuSelectionManager defaultManager() { synchronized (MENU_SELECTION_MANAGER_KEY) { AppContext context = AppContext.getAppContext(); MenuSelectionManager msm = (MenuSelectionManager) context.get(MENU_SELECTION_MANAGER_KEY); if (msm == null) { msm = new MenuSelectionManager(); context.put(MENU_SELECTION_MANAGER_KEY, msm); // installing additional listener if found in the AppContext Object o = context.get(SwingUtilities2.MENU_SELECTION_MANAGER_LISTENER_KEY); if (o != null && o instanceof ChangeListener) { msm.addChangeListener((ChangeListener) o); } } return msm; } } /** * Only one ChangeEvent is needed per button model instance since the * event's only state is the source property. The source of events * generated is always "this". */ protected transient ChangeEvent changeEvent = null; /** The collection of registered listeners */ protected EventListenerList listenerList = new EventListenerList(); /** * Changes the selection in the menu hierarchy. The elements * in the array are sorted in order from the root menu * element to the currently selected menu element. * <p> * Note that this method is public but is used by the look and * feel engine and should not be called by client applications. * * @param path an array of <code>MenuElement</code> objects specifying * the selected path */ public void setSelectedPath(MenuElement[] path) { int i, c; int currentSelectionCount = selection.size(); int firstDifference = 0; if (path == null) { path = new MenuElement[0]; } if (DEBUG) { System.out.print("Previous: "); printMenuElementArray(getSelectedPath()); System.out.print("New: "); printMenuElementArray(path); } for (i = 0, c = path.length; i < c; i++) { if (i < currentSelectionCount && selection.elementAt(i) == path[i]) firstDifference++; else break; } for (i = currentSelectionCount - 1; i >= firstDifference; i--) { MenuElement me = selection.elementAt(i); selection.removeElementAt(i); me.menuSelectionChanged(false); } for (i = firstDifference, c = path.length; i < c; i++) { if (path[i] != null) { selection.addElement(path[i]); path[i].menuSelectionChanged(true); } } fireStateChanged(); } /** * Returns the path to the currently selected menu item * * @return an array of MenuElement objects representing the selected path */ public MenuElement[] getSelectedPath() { MenuElement[] res = new MenuElement[selection.size()]; int i, c; for (i = 0, c = selection.size(); i < c; i++) res[i] = selection.elementAt(i); return res; } /** * Tell the menu selection to close and unselect all the menu components. Call this method * when a choice has been made */ public void clearSelectedPath() { if (selection.size() > 0) { setSelectedPath(null); } } /** * Adds a ChangeListener to the button. * * @param l the listener to add */ public void addChangeListener(ChangeListener l) { listenerList.add(ChangeListener.class, l); } /** * Removes a ChangeListener from the button. * * @param l the listener to remove */ public void removeChangeListener(ChangeListener l) { listenerList.remove(ChangeListener.class, l); } /** * Returns an array of all the <code>ChangeListener</code>s added * to this MenuSelectionManager with addChangeListener(). * * @return all of the <code>ChangeListener</code>s added or an empty * array if no listeners have been added * @since 1.4 */ public ChangeListener[] getChangeListeners() { return listenerList.getListeners(ChangeListener.class); } /** * Notifies all listeners that have registered interest for * notification on this event type. The event instance * is created lazily. * * @see EventListenerList */ protected void fireStateChanged() { // Guaranteed to return a non-null array Object[] listeners = listenerList.getListenerList(); // Process the listeners last to first, notifying // those that are interested in this event for (int i = listeners.length - 2; i >= 0; i -= 2) { if (listeners[i] == ChangeListener.class) { // Lazily create the event: if (changeEvent == null) changeEvent = new ChangeEvent(this); ((ChangeListener) listeners[i + 1]).stateChanged(changeEvent); } } } /** * When a MenuElement receives an event from a MouseListener, it should never process the event * directly. Instead all MenuElements should call this method with the event. * * @param event a MouseEvent object */ @SuppressWarnings("deprecation") public void processMouseEvent(MouseEvent event) { int screenX, screenY; Point p; int i, c, j, d; Component mc; Rectangle r2; int cWidth, cHeight; MenuElement menuElement; MenuElement[] subElements; MenuElement[] path; int selectionSize; p = event.getPoint(); Component source = event.getComponent(); if ((source != null) && !source.isShowing()) { // This can happen if a mouseReleased removes the // containing component -- bug 4146684 return; } int type = event.getID(); int modifiers = event.getModifiers(); // 4188027: drag enter/exit added in JDK 1.1.7A, JDK1.2 if ((type == MouseEvent.MOUSE_ENTERED || type == MouseEvent.MOUSE_EXITED) && ((modifiers & (InputEvent.BUTTON1_MASK | InputEvent.BUTTON2_MASK | InputEvent.BUTTON3_MASK)) != 0)) { return; } if (source != null) { SwingUtilities.convertPointToScreen(p, source); } screenX = p.x; screenY = p.y; @SuppressWarnings("unchecked") Vector<MenuElement> tmp = (Vector<MenuElement>) selection.clone(); selectionSize = tmp.size(); boolean success = false; for (i = selectionSize - 1; i >= 0 && success == false; i--) { menuElement = tmp.elementAt(i); subElements = menuElement.getSubElements(); path = null; for (j = 0, d = subElements.length; j < d && success == false; j++) { if (subElements[j] == null) continue; mc = subElements[j].getComponent(); if (!mc.isShowing()) continue; if (mc instanceof JComponent) { cWidth = mc.getWidth(); cHeight = mc.getHeight(); } else { r2 = mc.getBounds(); cWidth = r2.width; cHeight = r2.height; } p.x = screenX; p.y = screenY; SwingUtilities.convertPointFromScreen(p, mc); /** Send the event to visible menu element if menu element currently in * the selected path or contains the event location */ if ((p.x >= 0 && p.x < cWidth && p.y >= 0 && p.y < cHeight)) { int k; if (path == null) { path = new MenuElement[i + 2]; for (k = 0; k <= i; k++) path[k] = tmp.elementAt(k); } path[i + 1] = subElements[j]; MenuElement[] currentSelection = getSelectedPath(); // Enter/exit detection -- needs tuning... if (currentSelection[currentSelection.length - 1] != path[i + 1] && (currentSelection.length < 2 || currentSelection[currentSelection.length - 2] != path[i + 1])) { Component oldMC = currentSelection[currentSelection.length - 1].getComponent(); MouseEvent exitEvent = new MouseEvent(oldMC, MouseEvent.MOUSE_EXITED, event.getWhen(), event.getModifiers(), p.x, p.y, event.getXOnScreen(), event.getYOnScreen(), event.getClickCount(), event.isPopupTrigger(), MouseEvent.NOBUTTON); MouseEventAccessor meAccessor = AWTAccessor.getMouseEventAccessor(); meAccessor.setCausedByTouchEvent(exitEvent, meAccessor.isCausedByTouchEvent(event)); currentSelection[currentSelection.length - 1].processMouseEvent(exitEvent, path, this); MouseEvent enterEvent = new MouseEvent(mc, MouseEvent.MOUSE_ENTERED, event.getWhen(), event.getModifiers(), p.x, p.y, event.getXOnScreen(), event.getYOnScreen(), event.getClickCount(), event.isPopupTrigger(), MouseEvent.NOBUTTON); meAccessor.setCausedByTouchEvent(enterEvent, meAccessor.isCausedByTouchEvent(event)); subElements[j].processMouseEvent(enterEvent, path, this); } MouseEvent mouseEvent = new MouseEvent(mc, event.getID(), event.getWhen(), event.getModifiers(), p.x, p.y, event.getXOnScreen(), event.getYOnScreen(), event.getClickCount(), event.isPopupTrigger(), MouseEvent.NOBUTTON); MouseEventAccessor meAccessor = AWTAccessor.getMouseEventAccessor(); meAccessor.setCausedByTouchEvent(mouseEvent, meAccessor.isCausedByTouchEvent(event)); subElements[j].processMouseEvent(mouseEvent, path, this); success = true; event.consume(); } } } } private void printMenuElementArray(MenuElement[] path) { printMenuElementArray(path, false); } private void printMenuElementArray(MenuElement[] path, boolean dumpStack) { System.out.println("Path is("); int i, j; for (i = 0, j = path.length; i < j; i++) { for (int k = 0; k <= i; k++) System.out.print(" "); MenuElement me = path[i]; if (me instanceof JMenuItem) { System.out.println(((JMenuItem) me).getText() + ", "); } else if (me instanceof JMenuBar) { System.out.println("JMenuBar, "); } else if (me instanceof JPopupMenu) { System.out.println("JPopupMenu, "); } else if (me == null) { System.out.println("NULL , "); } else { System.out.println("" + me + ", "); } } System.out.println(")"); if (dumpStack == true) Thread.dumpStack(); } /** * Returns the component in the currently selected path * which contains sourcePoint. * * @param source The component in whose coordinate space sourcePoint * is given * @param sourcePoint The point which is being tested * @return The component in the currently selected path which * contains sourcePoint (relative to the source component's * coordinate space. If sourcePoint is not inside a component * on the currently selected path, null is returned. */ public Component componentForPoint(Component source, Point sourcePoint) { int screenX, screenY; Point p = sourcePoint; int i, c, j, d; Component mc; Rectangle r2; int cWidth, cHeight; MenuElement menuElement; MenuElement[] subElements; int selectionSize; SwingUtilities.convertPointToScreen(p, source); screenX = p.x; screenY = p.y; @SuppressWarnings("unchecked") Vector<MenuElement> tmp = (Vector<MenuElement>) selection.clone(); selectionSize = tmp.size(); for (i = selectionSize - 1; i >= 0; i--) { menuElement = tmp.elementAt(i); subElements = menuElement.getSubElements(); for (j = 0, d = subElements.length; j < d; j++) { if (subElements[j] == null) continue; mc = subElements[j].getComponent(); if (!mc.isShowing()) continue; if (mc instanceof JComponent) { cWidth = mc.getWidth(); cHeight = mc.getHeight(); } else { r2 = mc.getBounds(); cWidth = r2.width; cHeight = r2.height; } p.x = screenX; p.y = screenY; SwingUtilities.convertPointFromScreen(p, mc); /** Return the deepest component on the selection * path in whose bounds the event's point occurs */ if (p.x >= 0 && p.x < cWidth && p.y >= 0 && p.y < cHeight) { return mc; } } } return null; } /** * When a MenuElement receives an event from a KeyListener, it should never process the event * directly. Instead all MenuElements should call this method with the event. * * @param e a KeyEvent object */ public void processKeyEvent(KeyEvent e) { MenuElement[] sel2 = new MenuElement[0]; sel2 = selection.toArray(sel2); int selSize = sel2.length; MenuElement[] path; if (selSize < 1) { return; } for (int i = selSize - 1; i >= 0; i--) { MenuElement elem = sel2[i]; MenuElement[] subs = elem.getSubElements(); path = null; for (int j = 0; j < subs.length; j++) { if (subs[j] == null || !subs[j].getComponent().isShowing() || !subs[j].getComponent().isEnabled()) { continue; } if (path == null) { path = new MenuElement[i + 2]; System.arraycopy(sel2, 0, path, 0, i + 1); } path[i + 1] = subs[j]; subs[j].processKeyEvent(e, path, this); if (e.isConsumed()) { return; } } } // finally dispatch event to the first component in path path = new MenuElement[1]; path[0] = sel2[0]; path[0].processKeyEvent(e, path, this); if (e.isConsumed()) { return; } } /** * Return true if {@code c} is part of the currently used menu * * @param c a {@code Component} * @return true if {@code c} is part of the currently used menu, * false otherwise */ public boolean isComponentPartOfCurrentMenu(Component c) { if (selection.size() > 0) { MenuElement me = selection.elementAt(0); return isComponentPartOfCurrentMenu(me, c); } else return false; } private boolean isComponentPartOfCurrentMenu(MenuElement root, Component c) { MenuElement[] children; int i, d; if (root == null) return false; if (root.getComponent() == c) return true; else { children = root.getSubElements(); for (i = 0, d = children.length; i < d; i++) { if (isComponentPartOfCurrentMenu(children[i], c)) return true; } } return false; } }