227 lines
7.9 KiB
Java
227 lines
7.9 KiB
Java
/* MouseWheelEvent.java -- a mouse wheel event
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Copyright (C) 2002, 2005 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301 USA.
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package java.awt.event;
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import java.awt.Component;
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/**
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* This event is generated for a mouse wheel rotation. The wheel (the middle
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* mouse button on most modern mice) can be rotated towards or away from the
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* user, and is ofteh used for scrolling.
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*
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* <p>Because of the special use for scrolling components, MouseWheelEvents
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* often affect a different component than the one located at the point of
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* the event. If the component under the mouse cursor does not accept wheel
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* events, the event is passed to the first ancestor container which does. This
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* is often a ScrollPane, which knows how to scroll. If an AWT component is
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* built from a native widget that knows how to use mouse wheel events, that
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* component will consume the event.
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*
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* <p>The two most common scroll types are "units" (lines at a time) or
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* "blocks" (pages at a time). The initial setting is taken from the platform,
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* although the user can adjust the setting at any time.
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*
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* @author Eric Blake (ebb9@email.byu.edu)
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* @see MouseWheelListener
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* @see ScrollPane
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* @see ScrollPane#setWheelScrollingEnabled(boolean)
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* @see JScrollPane
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* @see JScrollPane#setWheelScrollingEnabled(boolean)
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* @since 1.4
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* @status updated to 1.4
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*/
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public class MouseWheelEvent extends MouseEvent
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{
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/**
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* Compatible with JDK 1.4+.
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*/
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private static final long serialVersionUID = 6459879390515399677L;
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/**
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* Indicates scrolling by units (lines).
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*
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* @see #getScrollType()
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*/
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public static final int WHEEL_UNIT_SCROLL = 0;
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/**
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* Indicates scrolling by blocks (pages).
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*
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* @see #getScrollType()
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*/
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public static final int WHEEL_BLOCK_SCROLL = 1;
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/**
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* Indicates what scroll type should take place. This should be limited
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* to {@link #WHEEL_UNIT_SCROLL} and {@link #WHEEL_BLOCK_SCROLL}.
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*
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* @serial the scroll type
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*/
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private final int scrollType;
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/**
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* Indicates the scroll amount. This is only meaningful if scrollType is
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* WHEEL_UNIT_SCROLL.
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*
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* @serial the number of lines to scroll
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*/
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private final int scrollAmount;
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/**
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* Indicates how far the mouse wheel was rotated.
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*
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* @serial the rotation amount
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*/
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private final int wheelRotation;
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/**
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* Initializes a new instance of <code>MouseWheelEvent</code> with the
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* specified information. Note that an invalid id leads to unspecified
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* results.
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*
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* @param source the source of the event
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* @param id the event id
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* @param when the timestamp of when the event occurred
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* @param modifiers any modifier bits for this event
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* @param x the X coordinate of the mouse point
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* @param y the Y coordinate of the mouse point
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* @param clickCount the number of mouse clicks for this event
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* @param popupTrigger true if this event triggers a popup menu
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* @param scrollType one of {@link #WHEEL_UNIT_SCROLL},
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* {@link #WHEEL_BLOCK_SCROLL}
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* @param scrollAmount the number of units to scroll, ignored for block type
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* @param wheelRotation the number of rotation "clicks"
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* @throws IllegalArgumentException if source is null
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* @see MouseEvent#MouseEvent(Component, int, long, int, int, int, int,
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* boolean)
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*/
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public MouseWheelEvent(Component source, int id, long when, int modifiers,
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int x, int y, int clickCount, boolean popupTrigger,
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int scrollType, int scrollAmount, int wheelRotation)
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{
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super(source, id, when, modifiers, x, y, clickCount, popupTrigger);
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this.scrollType = scrollType;
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this.scrollAmount = scrollAmount;
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this.wheelRotation = wheelRotation;
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}
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/**
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* This method returns the scrolling pattern this event requests. Legal
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* values are WHEEL_UNIT_SCROLL and WHEEL_BLOCK_SCROLL.
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*
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* @return the scroll type
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* @see Adjustable#getUnitIncrement()
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* @see Adjustable#getBlockIncrement()
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* @see Scrollable#getScrollableUnitIncrement(Rectangle, int, int)
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* @see Scrollable#getScrollableBlockIncrement(Rectangle, int, int)
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*/
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public int getScrollType()
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{
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return scrollType;
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}
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/**
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* Returns the number of units to scroll in response to this event. This
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* only makes sense when the scroll type is WHEEL_UNIT_SCROLL.
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*
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* @return the number of scroll units, if defined
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* @see #getScrollType()
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*/
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public int getScrollAmount()
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{
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return scrollAmount;
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}
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/**
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* Gets the number of "clicks" the wheel was rotated. Negative values move
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* up (away) from the user, positive values move down (towards) the user.
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*
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* @return the number of rotation clicks
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*/
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public int getWheelRotation()
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{
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return wheelRotation;
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}
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/**
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* This is a convenience method which aids in a common listener for scrolling
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* a scrollpane (although this is already built into ScrollPane and
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* JScrollPane). This method only makes sense when getScrollType() returns
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* WHEEL_UNIT_SCROLL.
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*
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* <p>This accounts for direction of scroll and amount of wheel movement, as
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* interpreted by the platform settings.
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*
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* @return the number of units to scroll
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* @see #getScrollType()
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* @see #getScrollAmount()
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* @see MouseWheelListener
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* @see Adjustable
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* @see Adjustable#getUnitIncrement()
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* @see Scrollable
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* @see Scrollable#getScrollableUnitIncrement(Rectangle, int, int)
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* @see ScrollPane
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* @see ScrollPane#setWheelScrollingEnabled(boolean)
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* @see JScrollPane
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* @see JScrollPane#setWheelScrollingEnabled(boolean)
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*/
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public int getUnitsToScroll()
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{
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return wheelRotation * scrollAmount;
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}
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/**
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* Returns a string identifying this event. For mouse wheel events, this
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* is <code>super.paramString() + ",scrollType=WHEEL_" +
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* (getScrollType() == WHEEL_UNIT_SCROLL ? "UNIT" : "BLOCK")
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* + "_SCROLL,scrollAmount=" + getScrollAmount() + ",wheelRotation="
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* + getWheelRotation()</code>.
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*
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* @return a string identifying this event
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*/
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public String paramString()
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{
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return super.paramString() + ",scrollType="
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+ (scrollType == WHEEL_UNIT_SCROLL ? "WHEEL_UNIT_SCROLL"
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: scrollType == WHEEL_BLOCK_SCROLL ? "WHEEL_BLOCK_SCROLL"
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: "unknown scroll type")
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+ ",scrollAmount=" + scrollAmount + ",wheelRotation=" + wheelRotation;
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}
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} // class MouseWheelEvent
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