<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN">
<!--NewPage-->
<HTML>
<HEAD>
<!-- Generated by javadoc on Tue Jun 29 05:58:01 GMT+01:00 1999 -->
<TITLE>
Swing 1.1 API Specification: Class  EventListenerList
</TITLE>
<LINK REL ="stylesheet" TYPE="text/css" HREF="../../../stylesheet.css" TITLE="Style">
</HEAD>
<BODY BGCOLOR="white">

<!-- ========== START OF NAVBAR ========== -->
<A NAME="navbar_top"><!-- --></A>
<TABLE BORDER="0" WIDTH="100%" CELLPADDING="1" CELLSPACING="0">
<TR>
<TD COLSPAN=2 BGCOLOR="#EEEEFF" ID="NavBarCell1">
<A NAME="navbar_top_firstrow"><!-- --></A>
<TABLE BORDER="0" CELLPADDING="0" CELLSPACING="3">
  <TR ALIGN="center" VALIGN="top">
  <TD BGCOLOR="#EEEEFF" ID="NavBarCell1">    <A HREF="../../../overview-summary.html"><FONT ID="NavBarFont1"><B>Overview</B></FONT></A>&nbsp;</TD>
  <TD BGCOLOR="#EEEEFF" ID="NavBarCell1">    <A HREF="package-summary.html"><FONT ID="NavBarFont1"><B>Package</B></FONT></A>&nbsp;</TD>
  <TD BGCOLOR="#FFFFFF" ID="NavBarCell1Rev"> &nbsp;<FONT ID="NavBarFont1Rev"><B>Class</B></FONT>&nbsp;</TD>
  <TD BGCOLOR="#EEEEFF" ID="NavBarCell1">    <A HREF="class-use/EventListenerList.html"><FONT ID="NavBarFont1"><B>Use</B></FONT></A>&nbsp;</TD>
  <TD BGCOLOR="#EEEEFF" ID="NavBarCell1">    <A HREF="package-tree.html"><FONT ID="NavBarFont1"><B>Tree</B></FONT></A>&nbsp;</TD>
  <TD BGCOLOR="#EEEEFF" ID="NavBarCell1">    <A HREF="../../../deprecated-list.html"><FONT ID="NavBarFont1"><B>Deprecated</B></FONT></A>&nbsp;</TD>
  <TD BGCOLOR="#EEEEFF" ID="NavBarCell1">    <A HREF="../../../index-files/index-1.html"><FONT ID="NavBarFont1"><B>Index</B></FONT></A>&nbsp;</TD>
  <TD BGCOLOR="#EEEEFF" ID="NavBarCell1">    <A HREF="../../../help-doc.html"><FONT ID="NavBarFont1"><B>Help</B></FONT></A>&nbsp;</TD>
  </TR>
</TABLE>
</TD>
<TD ALIGN="right" VALIGN="top" ROWSPAN=3><EM>
Swing 1.1</EM>
</TD>
</TR>

<TR>
<TD BGCOLOR="white" ID="NavBarCell2"><FONT SIZE="-2">
&nbsp;<A HREF="../../../javax/swing/event/DocumentEvent.EventType.html"><B>PREV CLASS</B></A>&nbsp;
&nbsp;<A HREF="../../../javax/swing/event/HyperlinkEvent.html"><B>NEXT CLASS</B></A></FONT></TD>
<TD BGCOLOR="white" ID="NavBarCell2"><FONT SIZE="-2">
  <A HREF="../../../index.html" TARGET="_top"><B>FRAMES</B></A>  &nbsp;
&nbsp;<A HREF="EventListenerList.html" TARGET="_top"><B>NO FRAMES</B></A></FONT></TD>
</TR>
<TR>
<TD VALIGN="top" ID="NavBarCell3"><FONT SIZE="-2">
  SUMMARY: &nbsp;INNER&nbsp;|&nbsp;<A HREF="#field_summary">FIELD</A>&nbsp;|&nbsp;<A HREF="#constructor_summary">CONSTR</A>&nbsp;|&nbsp;<A HREF="#method_summary">METHOD</A></FONT></TD>
<TD VALIGN="top" ID="NavBarCell3"><FONT SIZE="-2">
DETAIL: &nbsp;<A HREF="#field_detail">FIELD</A>&nbsp;|&nbsp;<A HREF="#constructor_detail">CONSTR</A>&nbsp;|&nbsp;<A HREF="#method_detail">METHOD</A></FONT></TD>
</TR>
</TABLE>
<!-- =========== END OF NAVBAR =========== -->

<HR>
<!-- ======== START OF CLASS DATA ======== -->
<H2>
<FONT SIZE="-1">
javax.swing.event</FONT>
<BR>
Class  EventListenerList</H2>
<PRE>
java.lang.Object
  |
  +--<B>javax.swing.event.EventListenerList</B>
</PRE>
<HR>
<DL>
<DT>public class <B>EventListenerList</B><DT>extends java.lang.Object<DT>implements java.io.Serializable</DL>

<P>
A class which holds a list of EventListeners.  A single instance
 can be used to hold all listeners (of all types) for the instance
 using the lsit.  It is the responsiblity of the class using the
 EventListenerList to provide type-safe API (preferably conforming
 to the JavaBeans spec) and methods which dispatch event notification
 methods to appropriate Event Listeners on the list.
 
 The main benefits which this class provides are that it is relatively
 cheap in the case of no listeners, and provides serialization for 
 eventlistener lists in a single place, as well as a degree of MT safety
 (when used correctly).

 Usage example:
    Say one is defining a class which sends out FooEvents, and wantds
 to allow users of the class to register FooListeners and receive 
 notification when FooEvents occur.  The following should be added
 to the class definition:
<pre>
EventListenerList listenrList = new EventListnerList();
FooEvent fooEvent = null;

public void addFooListener(FooListener l) {
listenerList.add(FooListener.class, l);
}

public void removeFooListener(FooListener l) {
listenerList.remove(FooListener.class, l);
}


// Notify all listeners that have registered interest for
// notification on this event type.  The event instance 
// is lazily created using the parameters passed into 
// the fire method.

protected void firefooXXX() {
// 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]==FooListener.class) {
// Lazily create the event:
if (fooEvent == null)
fooEvent = new FooEvent(this);
((FooListener)listeners[i+1]).fooXXX(fooEvent);
}	       
}
}	
</pre>
 foo should be changed to the appropriate name, and Method to the
 appropriate method name (one fire method should exist for each
 notification method in the FooListener interface).
 <p>
 <strong>Warning:</strong>
 Serialized objects of this class will not be compatible with 
 future Swing releases.  The current serialization support is appropriate
 for short term storage or RMI between applications running the same
 version of Swing.  A future release of Swing will provide support for
 long term persistence.
<P>
<DL>
<DT><B>See Also: </B><DD><A HREF="../../../serialized-form.html#javax.swing.event.EventListenerList">Serialized Form</A></DL>
<HR>

<P>
<!-- ======== INNER CLASS SUMMARY ======== -->


<!-- =========== FIELD SUMMARY =========== -->

<A NAME="field_summary"><!-- --></A>
<TABLE BORDER="1" CELLPADDING="3" CELLSPACING="0" WIDTH="100%">
<TR BGCOLOR="#CCCCFF" ID="TableHeadingColor">
<TD COLSPAN=2><FONT SIZE="+2">
<B>Field Summary</B></FONT></TD>
</TR>
<TR BGCOLOR="white" ID="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>protected &nbsp;java.lang.Object[]</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../javax/swing/event/EventListenerList.html#listenerList">listenerList</A></B></CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</TD>
</TR>
</TABLE>
&nbsp;
<!-- ======== CONSTRUCTOR SUMMARY ======== -->

<A NAME="constructor_summary"><!-- --></A>
<TABLE BORDER="1" CELLPADDING="3" CELLSPACING="0" WIDTH="100%">
<TR BGCOLOR="#CCCCFF" ID="TableHeadingColor">
<TD COLSPAN=2><FONT SIZE="+2">
<B>Constructor Summary</B></FONT></TD>
</TR>
<TR BGCOLOR="white" ID="TableRowColor">
<TD><CODE><B><A HREF="../../../javax/swing/event/EventListenerList.html#EventListenerList()">EventListenerList</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</TD>
</TR>
</TABLE>
&nbsp;
<!-- ========== METHOD SUMMARY =========== -->

<A NAME="method_summary"><!-- --></A>
<TABLE BORDER="1" CELLPADDING="3" CELLSPACING="0" WIDTH="100%">
<TR BGCOLOR="#CCCCFF" ID="TableHeadingColor">
<TD COLSPAN=2><FONT SIZE="+2">
<B>Method Summary</B></FONT></TD>
</TR>
<TR BGCOLOR="white" ID="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;void</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../javax/swing/event/EventListenerList.html#add(java.lang.Class, java.util.EventListener)">add</A></B>(java.lang.Class&nbsp;t,
    java.util.EventListener&nbsp;l)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Add the listener as a listener of the specified type.</TD>
</TR>
<TR BGCOLOR="white" ID="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;int</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../javax/swing/event/EventListenerList.html#getListenerCount()">getListenerCount</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Return the total number of listeners for this listenerlist</TD>
</TR>
<TR BGCOLOR="white" ID="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;int</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../javax/swing/event/EventListenerList.html#getListenerCount(java.lang.Class)">getListenerCount</A></B>(java.lang.Class&nbsp;t)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Return the total number of listeners of the supplied type 
 for this listenerlist.</TD>
</TR>
<TR BGCOLOR="white" ID="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;java.lang.Object[]</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../javax/swing/event/EventListenerList.html#getListenerList()">getListenerList</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;This passes back the event listener list as an array
 of ListenerType - listener pairs.</TD>
</TR>
<TR BGCOLOR="white" ID="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;void</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../javax/swing/event/EventListenerList.html#remove(java.lang.Class, java.util.EventListener)">remove</A></B>(java.lang.Class&nbsp;t,
       java.util.EventListener&nbsp;l)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Remove the listener as a listener of the specified type.</TD>
</TR>
<TR BGCOLOR="white" ID="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;java.lang.String</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../javax/swing/event/EventListenerList.html#toString()">toString</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Return a string representation of the EventListenerList.</TD>
</TR>
</TABLE>
&nbsp;<A NAME="methods_inherited_from_class_java.lang.Object"><!-- --></A>
<TABLE BORDER="1" CELLPADDING="3" CELLSPACING="0" WIDTH="100%">
<TR BGCOLOR="#EEEEFF" ID="TableSubHeadingColor">
<TD><B>Methods inherited from class java.lang.Object</B></TD>
</TR>
<TR BGCOLOR="white" ID="TableRowColor">
<TD><CODE>clone, 
equals, 
finalize, 
getClass, 
hashCode, 
notify, 
notifyAll, 
wait, 
wait, 
wait</CODE></TD>
</TR>
</TABLE>
&nbsp;
<P>

<!-- ============ FIELD DETAIL =========== -->

<A NAME="field_detail"><!-- --></A>
<TABLE BORDER="1" CELLPADDING="3" CELLSPACING="0" WIDTH="100%">
<TR BGCOLOR="#CCCCFF" ID="TableHeadingColor">
<TD COLSPAN=1><FONT SIZE="+2">
<B>Field Detail</B></FONT></TD>
</TR>
</TABLE>

<A NAME="listenerList"><!-- --></A><H3>
listenerList</H3>
<PRE>
protected transient java.lang.Object[] <B>listenerList</B></PRE>
<DL>
</DL>

<!-- ========= CONSTRUCTOR DETAIL ======== -->

<A NAME="constructor_detail"><!-- --></A>
<TABLE BORDER="1" CELLPADDING="3" CELLSPACING="0" WIDTH="100%">
<TR BGCOLOR="#CCCCFF" ID="TableHeadingColor">
<TD COLSPAN=1><FONT SIZE="+2">
<B>Constructor Detail</B></FONT></TD>
</TR>
</TABLE>

<A NAME="EventListenerList()"><!-- --></A><H3>
EventListenerList</H3>
<PRE>
public <B>EventListenerList</B>()</PRE>
<DL>
</DL>

<!-- ============ METHOD DETAIL ========== -->

<A NAME="method_detail"><!-- --></A>
<TABLE BORDER="1" CELLPADDING="3" CELLSPACING="0" WIDTH="100%">
<TR BGCOLOR="#CCCCFF" ID="TableHeadingColor">
<TD COLSPAN=1><FONT SIZE="+2">
<B>Method Detail</B></FONT></TD>
</TR>
</TABLE>

<A NAME="getListenerList()"><!-- --></A><H3>
getListenerList</H3>
<PRE>
public java.lang.Object[] <B>getListenerList</B>()</PRE>
<DL>
<DD>This passes back the event listener list as an array
 of ListenerType - listener pairs.  Note that for 
 performance reasons, this implementation passes back 
 the actual data structure in which the listner data
 is stored internally!  
 This method is guaranteed to pass back a non-null
 array, so that no null-checking is required in 
 fire methods.  A zero-length array of Object should
 be returned if there are currently no listeners.
 
 WARNING!!! Absolutely NO modification of
 the data contained in this array should be made -- if
 any such manipulation is necessary, it should be done
 on a copy of the array returned rather than the array 
 itself.<DD><DL>
</DL>
</DD>
</DL>
<HR>

<A NAME="getListenerCount()"><!-- --></A><H3>
getListenerCount</H3>
<PRE>
public int <B>getListenerCount</B>()</PRE>
<DL>
<DD>Return the total number of listeners for this listenerlist<DD><DL>
</DL>
</DD>
</DL>
<HR>

<A NAME="getListenerCount(java.lang.Class)"><!-- --></A><H3>
getListenerCount</H3>
<PRE>
public int <B>getListenerCount</B>(java.lang.Class&nbsp;t)</PRE>
<DL>
<DD>Return the total number of listeners of the supplied type 
 for this listenerlist.<DD><DL>
</DL>
</DD>
</DL>
<HR>

<A NAME="add(java.lang.Class, java.util.EventListener)"><!-- --></A><H3>
add</H3>
<PRE>
public void <B>add</B>(java.lang.Class&nbsp;t,
                java.util.EventListener&nbsp;l)</PRE>
<DL>
<DD>Add the listener as a listener of the specified type.<DD><DL>
<DT><B>Parameters:</B><DD><CODE>t</CODE> - the type of the listener to be added<DD><CODE>l</CODE> - the listener to be added</DL>
</DD>
</DL>
<HR>

<A NAME="remove(java.lang.Class, java.util.EventListener)"><!-- --></A><H3>
remove</H3>
<PRE>
public void <B>remove</B>(java.lang.Class&nbsp;t,
                   java.util.EventListener&nbsp;l)</PRE>
<DL>
<DD>Remove the listener as a listener of the specified type.<DD><DL>
<DT><B>Parameters:</B><DD><CODE>t</CODE> - the type of the listener to be removed<DD><CODE>l</CODE> - the listener to be removed</DL>
</DD>
</DL>
<HR>

<A NAME="toString()"><!-- --></A><H3>
toString</H3>
<PRE>
public java.lang.String <B>toString</B>()</PRE>
<DL>
<DD>Return a string representation of the EventListenerList.<DD><DL>
<DT><B>Overrides:</B><DD>toString in class java.lang.Object</DL>
</DD>
</DL>
<!-- ========= END OF CLASS DATA ========= -->
<HR>

<!-- ========== START OF NAVBAR ========== -->
<A NAME="navbar_bottom"><!-- --></A>
<TABLE BORDER="0" WIDTH="100%" CELLPADDING="1" CELLSPACING="0">
<TR>
<TD COLSPAN=2 BGCOLOR="#EEEEFF" ID="NavBarCell1">
<A NAME="navbar_bottom_firstrow"><!-- --></A>
<TABLE BORDER="0" CELLPADDING="0" CELLSPACING="3">
  <TR ALIGN="center" VALIGN="top">
  <TD BGCOLOR="#EEEEFF" ID="NavBarCell1">    <A HREF="../../../overview-summary.html"><FONT ID="NavBarFont1"><B>Overview</B></FONT></A>&nbsp;</TD>
  <TD BGCOLOR="#EEEEFF" ID="NavBarCell1">    <A HREF="package-summary.html"><FONT ID="NavBarFont1"><B>Package</B></FONT></A>&nbsp;</TD>
  <TD BGCOLOR="#FFFFFF" ID="NavBarCell1Rev"> &nbsp;<FONT ID="NavBarFont1Rev"><B>Class</B></FONT>&nbsp;</TD>
  <TD BGCOLOR="#EEEEFF" ID="NavBarCell1">    <A HREF="class-use/EventListenerList.html"><FONT ID="NavBarFont1"><B>Use</B></FONT></A>&nbsp;</TD>
  <TD BGCOLOR="#EEEEFF" ID="NavBarCell1">    <A HREF="package-tree.html"><FONT ID="NavBarFont1"><B>Tree</B></FONT></A>&nbsp;</TD>
  <TD BGCOLOR="#EEEEFF" ID="NavBarCell1">    <A HREF="../../../deprecated-list.html"><FONT ID="NavBarFont1"><B>Deprecated</B></FONT></A>&nbsp;</TD>
  <TD BGCOLOR="#EEEEFF" ID="NavBarCell1">    <A HREF="../../../index-files/index-1.html"><FONT ID="NavBarFont1"><B>Index</B></FONT></A>&nbsp;</TD>
  <TD BGCOLOR="#EEEEFF" ID="NavBarCell1">    <A HREF="../../../help-doc.html"><FONT ID="NavBarFont1"><B>Help</B></FONT></A>&nbsp;</TD>
  </TR>
</TABLE>
</TD>
<TD ALIGN="right" VALIGN="top" ROWSPAN=3><EM>
Swing 1.1</EM>
</TD>
</TR>

<TR>
<TD BGCOLOR="white" ID="NavBarCell2"><FONT SIZE="-2">
&nbsp;<A HREF="../../../javax/swing/event/DocumentEvent.EventType.html"><B>PREV CLASS</B></A>&nbsp;
&nbsp;<A HREF="../../../javax/swing/event/HyperlinkEvent.html"><B>NEXT CLASS</B></A></FONT></TD>
<TD BGCOLOR="white" ID="NavBarCell2"><FONT SIZE="-2">
  <A HREF="../../../index.html" TARGET="_top"><B>FRAMES</B></A>  &nbsp;
&nbsp;<A HREF="EventListenerList.html" TARGET="_top"><B>NO FRAMES</B></A></FONT></TD>
</TR>
<TR>
<TD VALIGN="top" ID="NavBarCell3"><FONT SIZE="-2">
  SUMMARY: &nbsp;INNER&nbsp;|&nbsp;<A HREF="#field_summary">FIELD</A>&nbsp;|&nbsp;<A HREF="#constructor_summary">CONSTR</A>&nbsp;|&nbsp;<A HREF="#method_summary">METHOD</A></FONT></TD>
<TD VALIGN="top" ID="NavBarCell3"><FONT SIZE="-2">
DETAIL: &nbsp;<A HREF="#field_detail">FIELD</A>&nbsp;|&nbsp;<A HREF="#constructor_detail">CONSTR</A>&nbsp;|&nbsp;<A HREF="#method_detail">METHOD</A></FONT></TD>
</TR>
</TABLE>
<!-- =========== END OF NAVBAR =========== -->

<HR>
<font size="-1"><a href="http://java.sun.com/cgi-bin/bugreport.cgi">Submit a bug or feature</a><br>Java is a trademark or registered trademark of Sun Microsystems,  Inc. in the US and other countries.<br>Copyright 1993-1998 Sun Microsystems, Inc. 901 San Antonio Road,<br>Palo Alto, California, 94303, U.S.A.  All Rights Reserved.</font>
</BODY>
</HTML>
