Java tutorial
/* * Copyright (c) 1996, 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 java.awt; import java.awt.event.ActionEvent; import java.awt.event.AdjustmentEvent; import java.awt.event.ComponentEvent; import java.awt.event.FocusEvent; import java.awt.event.InputEvent; import java.awt.event.InputMethodEvent; import java.awt.event.ItemEvent; import java.awt.event.KeyEvent; import java.awt.event.MouseEvent; import java.awt.event.TextEvent; import java.awt.event.WindowEvent; import java.awt.peer.ComponentPeer; import java.awt.peer.LightweightPeer; import java.security.AccessControlContext; import java.security.AccessController; import java.util.EventObject; import sun.awt.AWTAccessor; /** * The root event class for all AWT events. * This class and its subclasses supersede the original * java.awt.Event class. * Subclasses of this root AWTEvent class defined outside of the * java.awt.event package should define event ID values greater than * the value defined by RESERVED_ID_MAX. * <p> * The event masks defined in this class are needed by Component subclasses * which are using Component.enableEvents() to select for event types not * selected by registered listeners. If a listener is registered on a * component, the appropriate event mask is already set internally by the * component. * <p> * The masks are also used to specify to which types of events an * AWTEventListener should listen. The masks are bitwise-ORed together * and passed to Toolkit.addAWTEventListener. * * @see Component#enableEvents * @see Toolkit#addAWTEventListener * * @see java.awt.event.ActionEvent * @see java.awt.event.AdjustmentEvent * @see java.awt.event.ComponentEvent * @see java.awt.event.ContainerEvent * @see java.awt.event.FocusEvent * @see java.awt.event.InputMethodEvent * @see java.awt.event.InvocationEvent * @see java.awt.event.ItemEvent * @see java.awt.event.HierarchyEvent * @see java.awt.event.KeyEvent * @see java.awt.event.MouseEvent * @see java.awt.event.MouseWheelEvent * @see java.awt.event.PaintEvent * @see java.awt.event.TextEvent * @see java.awt.event.WindowEvent * * @author Carl Quinn * @author Amy Fowler * @since 1.1 */ public abstract class AWTEvent extends EventObject { private byte[] bdata; /** * The event's id. * @serial * @see #getID() * @see #AWTEvent */ protected int id; /** * Controls whether or not the event is sent back down to the peer once the * source has processed it - false means it's sent to the peer; true means * it's not. Semantic events always have a 'true' value since they were * generated by the peer in response to a low-level event. * @serial * @see #consume * @see #isConsumed */ protected boolean consumed = false; /* * The event's AccessControlContext. */ private transient volatile AccessControlContext acc = AccessController.getContext(); /* * Returns the acc this event was constructed with. */ final AccessControlContext getAccessControlContext() { if (acc == null) { throw new SecurityException("AWTEvent is missing AccessControlContext"); } return acc; } transient boolean focusManagerIsDispatching = false; transient boolean isPosted; /** * Indicates whether this AWTEvent was generated by the system as * opposed to by user code. */ private transient boolean isSystemGenerated; /** * The event mask for selecting component events. */ public static final long COMPONENT_EVENT_MASK = 0x01; /** * The event mask for selecting container events. */ public static final long CONTAINER_EVENT_MASK = 0x02; /** * The event mask for selecting focus events. */ public static final long FOCUS_EVENT_MASK = 0x04; /** * The event mask for selecting key events. */ public static final long KEY_EVENT_MASK = 0x08; /** * The event mask for selecting mouse events. */ public static final long MOUSE_EVENT_MASK = 0x10; /** * The event mask for selecting mouse motion events. */ public static final long MOUSE_MOTION_EVENT_MASK = 0x20; /** * The event mask for selecting window events. */ public static final long WINDOW_EVENT_MASK = 0x40; /** * The event mask for selecting action events. */ public static final long ACTION_EVENT_MASK = 0x80; /** * The event mask for selecting adjustment events. */ public static final long ADJUSTMENT_EVENT_MASK = 0x100; /** * The event mask for selecting item events. */ public static final long ITEM_EVENT_MASK = 0x200; /** * The event mask for selecting text events. */ public static final long TEXT_EVENT_MASK = 0x400; /** * The event mask for selecting input method events. */ public static final long INPUT_METHOD_EVENT_MASK = 0x800; /** * The pseudo event mask for enabling input methods. * We're using one bit in the eventMask so we don't need * a separate field inputMethodsEnabled. */ static final long INPUT_METHODS_ENABLED_MASK = 0x1000; /** * The event mask for selecting paint events. */ public static final long PAINT_EVENT_MASK = 0x2000; /** * The event mask for selecting invocation events. */ public static final long INVOCATION_EVENT_MASK = 0x4000; /** * The event mask for selecting hierarchy events. */ public static final long HIERARCHY_EVENT_MASK = 0x8000; /** * The event mask for selecting hierarchy bounds events. */ public static final long HIERARCHY_BOUNDS_EVENT_MASK = 0x10000; /** * The event mask for selecting mouse wheel events. * @since 1.4 */ public static final long MOUSE_WHEEL_EVENT_MASK = 0x20000; /** * The event mask for selecting window state events. * @since 1.4 */ public static final long WINDOW_STATE_EVENT_MASK = 0x40000; /** * The event mask for selecting window focus events. * @since 1.4 */ public static final long WINDOW_FOCUS_EVENT_MASK = 0x80000; /** * WARNING: there are more mask defined privately. See * SunToolkit.GRAB_EVENT_MASK. */ /** * The maximum value for reserved AWT event IDs. Programs defining * their own event IDs should use IDs greater than this value. */ public static final int RESERVED_ID_MAX = 1999; /* * JDK 1.1 serialVersionUID */ private static final long serialVersionUID = -1825314779160409405L; static { /* ensure that the necessary native libraries are loaded */ Toolkit.loadLibraries(); if (!GraphicsEnvironment.isHeadless()) { initIDs(); } AWTAccessor.setAWTEventAccessor(new AWTAccessor.AWTEventAccessor() { public void setPosted(AWTEvent ev) { ev.isPosted = true; } public void setSystemGenerated(AWTEvent ev) { ev.isSystemGenerated = true; } public boolean isSystemGenerated(AWTEvent ev) { return ev.isSystemGenerated; } public AccessControlContext getAccessControlContext(AWTEvent ev) { return ev.getAccessControlContext(); } public byte[] getBData(AWTEvent ev) { return ev.bdata; } public void setBData(AWTEvent ev, byte[] bdata) { ev.bdata = bdata; } }); } /** * Initialize JNI field and method IDs for fields that may be * accessed from C. */ private static native void initIDs(); /** * Constructs an AWTEvent object from the parameters of a 1.0-style event. * * @param event the old-style event * @deprecated It is recommended that {@link #AWTEvent(Object, int)} be used * instead */ @Deprecated(since = "9") public AWTEvent(Event event) { this(event.target, event.id); } /** * Constructs an AWTEvent object with the specified source object and type. * * @param source the object where the event originated * @param id the event type */ public AWTEvent(Object source, int id) { super(source); this.id = id; switch (id) { case ActionEvent.ACTION_PERFORMED: case ItemEvent.ITEM_STATE_CHANGED: case AdjustmentEvent.ADJUSTMENT_VALUE_CHANGED: case TextEvent.TEXT_VALUE_CHANGED: consumed = true; break; default: } } /** * Retargets an event to a new source. This method is typically used to * retarget an event to a lightweight child Component of the original * heavyweight source. * <p> * This method is intended to be used only by event targeting subsystems, * such as client-defined KeyboardFocusManagers. It is not for general * client use. * * @param newSource the new Object to which the event should be dispatched * @since 1.4 */ public void setSource(Object newSource) { if (source == newSource) { return; } Component comp = null; if (newSource instanceof Component) { comp = (Component) newSource; while (comp != null && comp.peer != null && (comp.peer instanceof LightweightPeer)) { comp = comp.parent; } } synchronized (this) { source = newSource; if (comp != null) { ComponentPeer peer = comp.peer; if (peer != null) { nativeSetSource(peer); } } } } private native void nativeSetSource(ComponentPeer peer); /** * Returns the event type. * * @return the event's type id */ public int getID() { return id; } /** * Returns a String representation of this object. */ public String toString() { String srcName = null; if (source instanceof Component) { srcName = ((Component) source).getName(); } else if (source instanceof MenuComponent) { srcName = ((MenuComponent) source).getName(); } return getClass().getName() + "[" + paramString() + "] on " + (srcName != null ? srcName : source); } /** * Returns a string representing the state of this {@code Event}. * This method is intended to be used only for debugging purposes, and the * content and format of the returned string may vary between * implementations. The returned string may be empty but may not be * {@code null}. * * @return a string representation of this event */ public String paramString() { return ""; } /** * Consumes this event, if this event can be consumed. Only low-level, * system events can be consumed */ protected void consume() { switch (id) { case KeyEvent.KEY_PRESSED: case KeyEvent.KEY_RELEASED: case MouseEvent.MOUSE_PRESSED: case MouseEvent.MOUSE_RELEASED: case MouseEvent.MOUSE_MOVED: case MouseEvent.MOUSE_DRAGGED: case MouseEvent.MOUSE_ENTERED: case MouseEvent.MOUSE_EXITED: case MouseEvent.MOUSE_WHEEL: case InputMethodEvent.INPUT_METHOD_TEXT_CHANGED: case InputMethodEvent.CARET_POSITION_CHANGED: consumed = true; break; default: // event type cannot be consumed } } /** * Returns whether this event has been consumed. * * @return {@code true} if this event has been consumed; * otherwise {@code false} */ protected boolean isConsumed() { return consumed; } /** * Converts a new event to an old one (used for compatibility). * If the new event cannot be converted (because no old equivalent * exists) then this returns null. * * Note: this method is here instead of in each individual new * event class in java.awt.event because we don't want to make * it public and it needs to be called from java.awt. */ @SuppressWarnings("deprecation") Event convertToOld() { Object src = getSource(); int newid = id; switch (id) { case KeyEvent.KEY_PRESSED: case KeyEvent.KEY_RELEASED: KeyEvent ke = (KeyEvent) this; if (ke.isActionKey()) { newid = (id == KeyEvent.KEY_PRESSED ? Event.KEY_ACTION : Event.KEY_ACTION_RELEASE); } int keyCode = ke.getKeyCode(); if (keyCode == KeyEvent.VK_SHIFT || keyCode == KeyEvent.VK_CONTROL || keyCode == KeyEvent.VK_ALT) { return null; // suppress modifier keys in old event model. } // no mask for button1 existed in old Event - strip it out return new Event(src, ke.getWhen(), newid, 0, 0, Event.getOldEventKey(ke), (ke.getModifiers() & ~InputEvent.BUTTON1_MASK)); case MouseEvent.MOUSE_PRESSED: case MouseEvent.MOUSE_RELEASED: case MouseEvent.MOUSE_MOVED: case MouseEvent.MOUSE_DRAGGED: case MouseEvent.MOUSE_ENTERED: case MouseEvent.MOUSE_EXITED: MouseEvent me = (MouseEvent) this; // no mask for button1 existed in old Event - strip it out Event olde = new Event(src, me.getWhen(), newid, me.getX(), me.getY(), 0, (me.getModifiers() & ~InputEvent.BUTTON1_MASK)); olde.clickCount = me.getClickCount(); return olde; case FocusEvent.FOCUS_GAINED: return new Event(src, Event.GOT_FOCUS, null); case FocusEvent.FOCUS_LOST: return new Event(src, Event.LOST_FOCUS, null); case WindowEvent.WINDOW_CLOSING: case WindowEvent.WINDOW_ICONIFIED: case WindowEvent.WINDOW_DEICONIFIED: return new Event(src, newid, null); case ComponentEvent.COMPONENT_MOVED: if (src instanceof Frame || src instanceof Dialog) { Point p = ((Component) src).getLocation(); return new Event(src, 0, Event.WINDOW_MOVED, p.x, p.y, 0, 0); } break; case ActionEvent.ACTION_PERFORMED: ActionEvent ae = (ActionEvent) this; String cmd; if (src instanceof Button) { cmd = ((Button) src).getLabel(); } else if (src instanceof MenuItem) { cmd = ((MenuItem) src).getLabel(); } else { cmd = ae.getActionCommand(); } return new Event(src, 0, newid, 0, 0, 0, ae.getModifiers(), cmd); case ItemEvent.ITEM_STATE_CHANGED: ItemEvent ie = (ItemEvent) this; Object arg; if (src instanceof List) { newid = (ie.getStateChange() == ItemEvent.SELECTED ? Event.LIST_SELECT : Event.LIST_DESELECT); arg = ie.getItem(); } else { newid = Event.ACTION_EVENT; if (src instanceof Choice) { arg = ie.getItem(); } else { // Checkbox arg = Boolean.valueOf(ie.getStateChange() == ItemEvent.SELECTED); } } return new Event(src, newid, arg); case AdjustmentEvent.ADJUSTMENT_VALUE_CHANGED: AdjustmentEvent aje = (AdjustmentEvent) this; switch (aje.getAdjustmentType()) { case AdjustmentEvent.UNIT_INCREMENT: newid = Event.SCROLL_LINE_DOWN; break; case AdjustmentEvent.UNIT_DECREMENT: newid = Event.SCROLL_LINE_UP; break; case AdjustmentEvent.BLOCK_INCREMENT: newid = Event.SCROLL_PAGE_DOWN; break; case AdjustmentEvent.BLOCK_DECREMENT: newid = Event.SCROLL_PAGE_UP; break; case AdjustmentEvent.TRACK: if (aje.getValueIsAdjusting()) { newid = Event.SCROLL_ABSOLUTE; } else { newid = Event.SCROLL_END; } break; default: return null; } return new Event(src, newid, Integer.valueOf(aje.getValue())); default: } return null; } /** * Copies all private data from this event into that. * Space is allocated for the copied data that will be * freed when the that is finalized. Upon completion, * this event is not changed. */ void copyPrivateDataInto(AWTEvent that) { that.bdata = this.bdata; // Copy canAccessSystemClipboard value from this into that. if (this instanceof InputEvent && that instanceof InputEvent) { AWTAccessor.InputEventAccessor accessor = AWTAccessor.getInputEventAccessor(); boolean b = accessor.canAccessSystemClipboard((InputEvent) this); accessor.setCanAccessSystemClipboard((InputEvent) that, b); } that.isSystemGenerated = this.isSystemGenerated; } void dispatched() { if (this instanceof InputEvent) { AWTAccessor.getInputEventAccessor().setCanAccessSystemClipboard((InputEvent) this, false); } } } // class AWTEvent