📄 eventlistenerlist.html
字号:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Frameset//EN""http://www.w3.org/TR/REC-html40/frameset.dtd"><!--NewPage--><HTML><HEAD><!-- Generated by javadoc on Thu Apr 27 23:40:05 PDT 2000 --><TITLE>Java 2 Platform SE v1.3: 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" CLASS="NavBarCell1"><A NAME="navbar_top_firstrow"><!-- --></A><TABLE BORDER="0" CELLPADDING="0" CELLSPACING="3"> <TR ALIGN="center" VALIGN="top"> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../overview-summary.html"><FONT CLASS="NavBarFont1"><B>Overview</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="package-summary.html"><FONT CLASS="NavBarFont1"><B>Package</B></FONT></A> </TD> <TD BGCOLOR="#FFFFFF" CLASS="NavBarCell1Rev"> <FONT CLASS="NavBarFont1Rev"><B>Class</B></FONT> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="class-use/EventListenerList.html"><FONT CLASS="NavBarFont1"><B>Use</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="package-tree.html"><FONT CLASS="NavBarFont1"><B>Tree</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../deprecated-list.html"><FONT CLASS="NavBarFont1"><B>Deprecated</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../index-files/index-1.html"><FONT CLASS="NavBarFont1"><B>Index</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../help-doc.html"><FONT CLASS="NavBarFont1"><B>Help</B></FONT></A> </TD> </TR></TABLE></TD><TD ALIGN="right" VALIGN="top" ROWSPAN=3><EM><b>Java<sup><font size=-2>TM</font></sup> 2 Platform<br>Std. Ed. v1.3</b></EM></TD></TR><TR><TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../../javax/swing/event/DocumentEvent.EventType.html"><B>PREV CLASS</B></A> <A HREF="../../../javax/swing/event/HyperlinkEvent.html"><B>NEXT CLASS</B></A></FONT></TD><TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../../index.html" TARGET="_top"><B>FRAMES</B></A> <A HREF="EventListenerList.html" TARGET="_top"><B>NO FRAMES</B></A></FONT></TD></TR><TR><TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2"> SUMMARY: INNER | <A HREF="#field_summary">FIELD</A> | <A HREF="#constructor_summary">CONSTR</A> | <A HREF="#method_summary">METHOD</A></FONT></TD><TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2">DETAIL: <A HREF="#field_detail">FIELD</A> | <A HREF="#constructor_detail">CONSTR</A> | <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><A HREF="../../../java/lang/Object.html">java.lang.Object</A> | +--<B>javax.swing.event.EventListenerList</B></PRE><DL><DT><B>All Implemented Interfaces:</B> <DD><A HREF="../../../java/io/Serializable.html">Serializable</A></DD></DL><HR><DL><DT>public class <B>EventListenerList</B><DT>extends <A HREF="../../../java/lang/Object.html">Object</A><DT>implements <A HREF="../../../java/io/Serializable.html">Serializable</A></DL><P>A class that holds a list of EventListeners. A single instance can be used to hold all listeners (of all types) for the instance using the list. 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 that this class provides are that it is relatively cheap in the case of no listeners, and it provides serialization for event-listener lists in a single place, as well as a degree of MT safety (when used correctly). Usage example: Say one is defining a class that sends out FooEvents, and one wants 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 listenerList = new EventListenerList(); 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 fireFooXxx 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" CLASS="TableHeadingColor"><TD COLSPAN=2><FONT SIZE="+2"><B>Field Summary</B></FONT></TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>protected <A HREF="../../../java/lang/Object.html">Object</A>[]</CODE></FONT></TD><TD><CODE><B><A HREF="../../../javax/swing/event/EventListenerList.html#listenerList">listenerList</A></B></CODE><BR> </TD></TR></TABLE> <!-- ======== CONSTRUCTOR SUMMARY ======== --><A NAME="constructor_summary"><!-- --></A><TABLE BORDER="1" CELLPADDING="3" CELLSPACING="0" WIDTH="100%"><TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"><TD COLSPAN=2><FONT SIZE="+2"><B>Constructor Summary</B></FONT></TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD><CODE><B><A HREF="../../../javax/swing/event/EventListenerList.html#EventListenerList()">EventListenerList</A></B>()</CODE><BR> </TD></TR></TABLE> <!-- ========== METHOD SUMMARY =========== --><A NAME="method_summary"><!-- --></A><TABLE BORDER="1" CELLPADDING="3" CELLSPACING="0" WIDTH="100%"><TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"><TD COLSPAN=2><FONT SIZE="+2"><B>Method Summary</B></FONT></TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> void</CODE></FONT></TD><TD><CODE><B><A HREF="../../../javax/swing/event/EventListenerList.html#add(java.lang.Class, java.util.EventListener)">add</A></B>(<A HREF="../../../java/lang/Class.html">Class</A> t, <A HREF="../../../java/util/EventListener.html">EventListener</A> l)</CODE><BR> Adds the listener as a listener of the specified type.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> int</CODE></FONT></TD><TD><CODE><B><A HREF="../../../javax/swing/event/EventListenerList.html#getListenerCount()">getListenerCount</A></B>()</CODE><BR> Returns the total number of listeners for this listener list.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> int</CODE></FONT></TD><TD><CODE><B><A HREF="../../../javax/swing/event/EventListenerList.html#getListenerCount(java.lang.Class)">getListenerCount</A></B>(<A HREF="../../../java/lang/Class.html">Class</A> t)</CODE><BR> Returns the total number of listeners of the supplied type for this listener list.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> <A HREF="../../../java/lang/Object.html">Object</A>[]</CODE></FONT></TD><TD><CODE><B><A HREF="../../../javax/swing/event/EventListenerList.html#getListenerList()">getListenerList</A></B>()</CODE><BR> Passes back the event listener list as an array of ListenerType-listener pairs.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> <A HREF="../../../java/util/EventListener.html">EventListener</A>[]</CODE></FONT></TD><TD><CODE><B><A HREF="../../../javax/swing/event/EventListenerList.html#getListeners(java.lang.Class)">getListeners</A></B>(<A HREF="../../../java/lang/Class.html">Class</A> t)</CODE><BR> Return an array of all the listeners of the given type.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor">⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -