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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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* published by the Free Software Foundation. Oracle designates this
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*
* 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).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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*/
package java.awt.event;
import java.awt.AWTEvent;
import java.awt.Component;
import java.awt.Rectangle;
/**
* A low-level event which indicates that a component moved, changed
* size, or changed visibility (also, the root class for the other
* component-level events).
* <P>
* Component events are provided for notification purposes ONLY;
* The AWT will automatically handle component moves and resizes
* internally so that GUI layout works properly regardless of
* whether a program is receiving these events or not.
* <P>
* In addition to serving as the base class for other component-related
* events (InputEvent, FocusEvent, WindowEvent, ContainerEvent),
* this class defines the events that indicate changes in
* a component's size, position, or visibility.
* <P>
* This low-level event is generated by a component object (such as a
* List) when the component is moved, resized, rendered invisible, or made
* visible again. The event is passed to every <code>ComponentListener</code>
* or <code>ComponentAdapter</code> object which registered to receive such
* events using the component's <code>addComponentListener</code> method.
* (<code>ComponentAdapter</code> objects implement the
* <code>ComponentListener</code> interface.) Each such listener object
* gets this <code>ComponentEvent</code> when the event occurs.
*
* @see ComponentAdapter
* @see ComponentListener
* @see <a href="http://java.sun.com/docs/books/tutorial/post1.0/ui/componentlistener.html">Tutorial: Writing a Component Listener</a>
*
* @author Carl Quinn
* @since 1.1
*/
public class ComponentEvent extends AWTEvent {
/**
* The first number in the range of ids used for component events.
*/
public static final int COMPONENT_FIRST = 100;
/**
* The last number in the range of ids used for component events.
*/
public static final int COMPONENT_LAST = 103;
/**
* This event indicates that the component's position changed.
*/
public static final int COMPONENT_MOVED = COMPONENT_FIRST;
/**
* This event indicates that the component's size changed.
*/
public static final int COMPONENT_RESIZED = 1 + COMPONENT_FIRST;
/**
* This event indicates that the component was made visible.
*/
public static final int COMPONENT_SHOWN = 2 + COMPONENT_FIRST;
/**
* This event indicates that the component was rendered invisible.
*/
public static final int COMPONENT_HIDDEN = 3 + COMPONENT_FIRST;
/*
* JDK 1.1 serialVersionUID
*/
private static final long serialVersionUID = 8101406823902992965L;
/**
* Constructs a <code>ComponentEvent</code> object.
* <p>Note that passing in an invalid <code>id</code> results in
* unspecified behavior. This method throws an
* <code>IllegalArgumentException</code> if <code>source</code>
* is <code>null</code>.
*
* @param source the <code>Component</code> that originated the event
* @param id an integer indicating the type of event
* @throws IllegalArgumentException if <code>source</code> is null
*/
public ComponentEvent(Component source, int id) {
super(source, id);
}
/**
* Returns the originator of the event.
*
* @return the <code>Component</code> object that originated
* the event, or <code>null</code> if the object is not a
* <code>Component</code>.
*/
public Component getComponent() {
return (source instanceof Component) ? (Component)source : null;
}
/**
* Returns a parameter string identifying this event.
* This method is useful for event-logging and for debugging.
*
* @return a string identifying the event and its attributes
*/
public String paramString() {
String typeStr;
Rectangle b = (source !=null
? ((Component)source).getBounds()
: null);
switch(id) {
case COMPONENT_SHOWN:
typeStr = "COMPONENT_SHOWN";
break;
case COMPONENT_HIDDEN:
typeStr = "COMPONENT_HIDDEN";
break;
case COMPONENT_MOVED:
typeStr = "COMPONENT_MOVED ("+
b.x+","+b.y+" "+b.width+"x"+b.height+")";
break;
case COMPONENT_RESIZED:
typeStr = "COMPONENT_RESIZED ("+
b.x+","+b.y+" "+b.width+"x"+b.height+")";
break;
default:
typeStr = "unknown type";
}
return typeStr;
}
}