441 lines
19 KiB
Java
441 lines
19 KiB
Java
/* java.beans.EventSetDescriptor
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Copyright (C) 1998 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., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 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.beans;
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import java.util.*;
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import java.lang.reflect.*;
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import gnu.java.lang.*;
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/**
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** EventSetDescriptor describes the hookup between an event source
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** class and an event listener class.
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**
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** EventSets have several attributes: the listener class, the events
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** that can be fired to the listener (methods in the listener class), and
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** an add and remove listener method from the event firer's class.<P>
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**
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** The methods have these constraints on them:<P>
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** <UL>
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** <LI>event firing methods: must have <CODE>void</CODE> return value. Any
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** parameters and exceptions are allowed. May be public, protected or
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** package-protected. (Don't ask me why that is, I'm just following the spec.
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** The only place it is even mentioned is in the Java Beans white paper, and
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** there it is only implied.)</LI>
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** <LI>add listener method: must have <CODE>void</CODE> return value. Must
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** take exactly one argument, of the listener class's type. May fire either
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** zero exceptions, or one exception of type <CODE>java.util.TooManyListenersException</CODE>.
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** Must be public.</LI>
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** <LI>remove listener method: must have <CODE>void</CODE> return value.
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** Must take exactly one argument, of the listener class's type. May not
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** fire any exceptions. Must be public.</LI>
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** </UL>
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**
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** A final constraint is that event listener classes must extend from EventListener.<P>
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**
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** There are also various design patterns associated with some of the methods
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** of construction. Those are explained in more detail in the appropriate
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** constructors.<P>
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**
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** <STRONG>Documentation Convention:</STRONG> for proper
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** Internalization of Beans inside an RAD tool, sometimes there
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** are two names for a property or method: a programmatic, or
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** locale-independent name, which can be used anywhere, and a
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** localized, display name, for ease of use. In the
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** documentation I will specify different String values as
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** either <EM>programmatic</EM> or <EM>localized</EM> to
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** make this distinction clear.
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**
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** @author John Keiser
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** @since JDK1.1
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** @version 1.1.0, 31 May 1998
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**/
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public class EventSetDescriptor extends FeatureDescriptor {
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private Method addListenerMethod;
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private Method removeListenerMethod;
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private Class listenerType;
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private MethodDescriptor[] listenerMethodDescriptors;
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private Method[] listenerMethods;
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private boolean unicast;
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private boolean inDefaultEventSet = true;
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/** Create a new EventSetDescriptor.
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** This version of the constructor enforces the rules imposed on the methods
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** described at the top of this class, as well as searching for:<P>
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** <OL>
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** <LI>The event-firing method must be non-private with signature
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** <CODE>void <listenerMethodName>(<eventSetName>Event)</CODE>
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** (where <CODE><eventSetName></CODE> has its first character capitalized
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** by the constructor and the Event is a descendant of
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** <CODE>java.util.EventObject</CODE>) in class <CODE>listenerType</CODE>
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** (any exceptions may be thrown).
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** <B>Implementation note:</B> Note that there could conceivably be multiple
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** methods with this type of signature (example: java.util.MouseEvent vs.
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** my.very.own.MouseEvent). In this implementation, all methods fitting the
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** description will be put into the <CODE>EventSetDescriptor</CODE>, even
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** though the spec says only one should be chosen (they probably weren't thinking as
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** pathologically as I was). I don't like arbitrarily choosing things.
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** If your class has only one such signature, as most do, you'll have no problems.</LI>
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** <LI>The add and remove methods must be public and named
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** <CODE>void add<eventSetName>Listener(<listenerType>)</CODE> and
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** <CODE>void remove<eventSetName>Listener(<listenerType>)</CODE> in
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** in class <CODE>eventSourceClass</CODE>, where
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** <CODE><eventSetName></CODE> will have its first letter capitalized.
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** Standard exception rules (see class description) apply.</LI>
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** </OL>
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** @param eventSourceClass the class containing the add/remove listener methods.
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** @param eventSetName the programmatic name of the event set, generally starting
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** with a lowercase letter (i.e. fooManChu instead of FooManChu). This will be used
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** to generate the name of the event object as well as the names of the add and
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** remove methods.
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** @param listenerType the class containing the event firing method.
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** @param listenerMethodName the name of the event firing method.
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** @exception IntrospectionException if listenerType is not an EventListener,
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** or if methods are not found or are invalid.
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**/
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public EventSetDescriptor(Class eventSourceClass,
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String eventSetName,
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Class listenerType,
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String listenerMethodName) throws IntrospectionException {
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setName(eventSetName);
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if(!java.util.EventListener.class.isAssignableFrom(listenerType)) {
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throw new IntrospectionException("Listener type is not an EventListener.");
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}
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String[] names = new String[1];
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names[0] = listenerMethodName;
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try {
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eventSetName = Character.toUpperCase(eventSetName.charAt(0)) + eventSetName.substring(1);
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} catch(StringIndexOutOfBoundsException e) {
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eventSetName = "";
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}
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findMethods(eventSourceClass,listenerType,names,"add"+eventSetName+"Listener","remove"+eventSetName+"Listener",eventSetName+"Event");
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this.listenerType = listenerType;
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checkAddListenerUnicast();
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if(this.removeListenerMethod.getExceptionTypes().length > 0) {
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throw new IntrospectionException("Listener remove method throws exceptions.");
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}
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}
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/** Create a new EventSetDescriptor.
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** This form of the constructor allows you to specify the names of the methods and adds
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** no new constraints on top of the rules already described at the top of the class.<P>
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**
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** @param eventSourceClass the class containing the add and remove listener methods.
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** @param eventSetName the programmatic name of the event set, generally starting
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** with a lowercase letter (i.e. fooManChu instead of FooManChu).
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** @param listenerType the class containing the event firing methods.
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** @param listenerMethodNames the names of the even firing methods.
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** @param addListenerMethodName the name of the add listener method.
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** @param removeListenerMethodName the name of the remove listener method.
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** @exception IntrospectionException if listenerType is not an EventListener
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** or if methods are not found or are invalid.
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**/
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public EventSetDescriptor(Class eventSourceClass,
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String eventSetName,
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Class listenerType,
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String[] listenerMethodNames,
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String addListenerMethodName,
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String removeListenerMethodName) throws IntrospectionException {
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setName(eventSetName);
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if(!java.util.EventListener.class.isAssignableFrom(listenerType)) {
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throw new IntrospectionException("Listener type is not an EventListener.");
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}
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findMethods(eventSourceClass,listenerType,listenerMethodNames,addListenerMethodName,removeListenerMethodName,null);
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this.listenerType = listenerType;
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checkAddListenerUnicast();
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if(this.removeListenerMethod.getExceptionTypes().length > 0) {
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throw new IntrospectionException("Listener remove method throws exceptions.");
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}
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}
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/** Create a new EventSetDescriptor.
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** This form of constructor allows you to explicitly say which methods do what, and
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** no reflection is done by the EventSetDescriptor. The methods are, however,
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** checked to ensure that they follow the rules set forth at the top of the class.
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** @param eventSetName the programmatic name of the event set, generally starting
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** with a lowercase letter (i.e. fooManChu instead of FooManChu).
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** @param listenerType the class containing the listenerMethods.
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** @param listenerMethods the event firing methods.
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** @param addListenerMethod the add listener method.
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** @param removeListenerMethod the remove listener method.
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** @exception IntrospectionException if the listenerType is not an EventListener,
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** or any of the methods are invalid.
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**/
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public EventSetDescriptor(String eventSetName,
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Class listenerType,
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Method[] listenerMethods,
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Method addListenerMethod,
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Method removeListenerMethod) throws IntrospectionException {
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setName(eventSetName);
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if(!java.util.EventListener.class.isAssignableFrom(listenerType)) {
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throw new IntrospectionException("Listener type is not an EventListener.");
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}
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this.listenerMethods = listenerMethods;
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this.addListenerMethod = addListenerMethod;
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this.removeListenerMethod = removeListenerMethod;
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this.listenerType = listenerType;
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checkMethods();
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checkAddListenerUnicast();
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if(this.removeListenerMethod.getExceptionTypes().length > 0) {
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throw new IntrospectionException("Listener remove method throws exceptions.");
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}
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}
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/** Create a new EventSetDescriptor.
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** This form of constructor allows you to explicitly say which methods do what, and
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** no reflection is done by the EventSetDescriptor. The methods are, however,
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** checked to ensure that they follow the rules set forth at the top of the class.
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** @param eventSetName the programmatic name of the event set, generally starting
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** with a lowercase letter (i.e. fooManChu instead of FooManChu).
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** @param listenerType the class containing the listenerMethods.
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** @param listenerMethodDescriptors the event firing methods.
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** @param addListenerMethod the add listener method.
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** @param removeListenerMethod the remove listener method.
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** @exception IntrospectionException if the listenerType is not an EventListener,
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** or any of the methods are invalid.
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**/
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public EventSetDescriptor(String eventSetName,
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Class listenerType,
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MethodDescriptor[] listenerMethodDescriptors,
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Method addListenerMethod,
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Method removeListenerMethod) throws IntrospectionException {
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setName(eventSetName);
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if(!java.util.EventListener.class.isAssignableFrom(listenerType)) {
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throw new IntrospectionException("Listener type is not an EventListener.");
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}
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this.listenerMethodDescriptors = listenerMethodDescriptors;
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this.listenerMethods = new Method[listenerMethodDescriptors.length];
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for(int i=0;i<this.listenerMethodDescriptors.length;i++) {
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this.listenerMethods[i] = this.listenerMethodDescriptors[i].getMethod();
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}
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this.addListenerMethod = addListenerMethod;
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this.removeListenerMethod = removeListenerMethod;
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this.listenerType = listenerType;
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checkMethods();
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checkAddListenerUnicast();
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if(this.removeListenerMethod.getExceptionTypes().length > 0) {
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throw new IntrospectionException("Listener remove method throws exceptions.");
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}
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}
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/** Get the class that contains the event firing methods. **/
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public Class getListenerType() {
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return listenerType;
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}
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/** Get the event firing methods. **/
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public Method[] getListenerMethods() {
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return listenerMethods;
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}
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/** Get the event firing methods as MethodDescriptors. **/
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public MethodDescriptor[] getListenerMethodDescriptors() {
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if(listenerMethodDescriptors == null) {
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listenerMethodDescriptors = new MethodDescriptor[listenerMethods.length];
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for(int i=0;i<listenerMethods.length;i++) {
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listenerMethodDescriptors[i] = new MethodDescriptor(listenerMethods[i]);
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}
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}
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return listenerMethodDescriptors;
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}
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/** Get the add listener method. **/
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public Method getAddListenerMethod() {
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return addListenerMethod;
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}
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/** Get the remove listener method. **/
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public Method getRemoveListenerMethod() {
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return removeListenerMethod;
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}
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/** Set whether or not multiple listeners may be added.
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** @param unicast whether or not multiple listeners may be added.
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**/
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public void setUnicast(boolean unicast) {
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this.unicast = unicast;
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}
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/** Get whether or not multiple listeners may be added. (Defaults to false.) **/
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public boolean isUnicast() {
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return unicast;
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}
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/** Set whether or not this is in the default event set.
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** @param inDefaultEventSet whether this is in the default event set.
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**/
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public void setInDefaultEventSet(boolean inDefaultEventSet) {
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this.inDefaultEventSet = inDefaultEventSet;
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}
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/** Get whether or not this is in the default event set. (Defaults to true.)**/
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public boolean isInDefaultEventSet() {
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return inDefaultEventSet;
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}
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private void checkAddListenerUnicast() throws IntrospectionException {
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Class[] addListenerExceptions = this.addListenerMethod.getExceptionTypes();
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if(addListenerExceptions.length > 1) {
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throw new IntrospectionException("Listener add method throws too many exceptions.");
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} else if(addListenerExceptions.length == 1
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&& !java.util.TooManyListenersException.class.isAssignableFrom(addListenerExceptions[0])) {
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throw new IntrospectionException("Listener add method throws too many exceptions.");
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}
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}
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private void checkMethods() throws IntrospectionException {
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if(!addListenerMethod.getDeclaringClass().isAssignableFrom(removeListenerMethod.getDeclaringClass())
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&& !removeListenerMethod.getDeclaringClass().isAssignableFrom(addListenerMethod.getDeclaringClass())) {
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throw new IntrospectionException("add and remove listener methods do not come from the same class. This is bad.");
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}
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if(!addListenerMethod.getReturnType().equals(java.lang.Void.TYPE)
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|| addListenerMethod.getParameterTypes().length != 1
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|| !listenerType.equals(addListenerMethod.getParameterTypes()[0])
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|| !Modifier.isPublic(addListenerMethod.getModifiers())) {
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throw new IntrospectionException("Add Listener Method invalid.");
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}
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if(!removeListenerMethod.getReturnType().equals(java.lang.Void.TYPE)
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|| removeListenerMethod.getParameterTypes().length != 1
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|| !listenerType.equals(removeListenerMethod.getParameterTypes()[0])
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|| removeListenerMethod.getExceptionTypes().length > 0
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|| !Modifier.isPublic(removeListenerMethod.getModifiers())) {
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throw new IntrospectionException("Remove Listener Method invalid.");
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}
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for(int i=0;i<listenerMethods.length;i++) {
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if(!listenerMethods[i].getReturnType().equals(java.lang.Void.TYPE)
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|| Modifier.isPrivate(listenerMethods[i].getModifiers())) {
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throw new IntrospectionException("Event Method " + listenerMethods[i].getName() + " non-void or private.");
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}
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if(!listenerMethods[i].getDeclaringClass().isAssignableFrom(listenerType)) {
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throw new IntrospectionException("Event Method " + listenerMethods[i].getName() + " not from class " + listenerType.getName());
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}
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}
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}
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private void findMethods(Class eventSourceClass,
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Class listenerType,
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String listenerMethodNames[],
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String addListenerMethodName,
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String removeListenerMethodName,
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String absurdEventClassCheckName) throws IntrospectionException {
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/* Find add listener method and remove listener method. */
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Class[] listenerArgList = new Class[1];
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listenerArgList[0] = listenerType;
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try {
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this.addListenerMethod = eventSourceClass.getMethod(addListenerMethodName,listenerArgList);
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} catch(SecurityException E) {
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throw new IntrospectionException("SecurityException trying to access method " + addListenerMethodName + ".");
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} catch(NoSuchMethodException E) {
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throw new IntrospectionException("Could not find method " + addListenerMethodName + ".");
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}
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if(this.addListenerMethod == null || !this.addListenerMethod.getReturnType().equals(java.lang.Void.TYPE)) {
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throw new IntrospectionException("Add listener method does not exist, is not public, or is not void.");
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}
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try {
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this.removeListenerMethod = eventSourceClass.getMethod(removeListenerMethodName,listenerArgList);
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} catch(SecurityException E) {
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throw new IntrospectionException("SecurityException trying to access method " + removeListenerMethodName + ".");
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} catch(NoSuchMethodException E) {
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throw new IntrospectionException("Could not find method " + removeListenerMethodName + ".");
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}
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if(this.removeListenerMethod == null || !this.removeListenerMethod.getReturnType().equals(java.lang.Void.TYPE)) {
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throw new IntrospectionException("Remove listener method does not exist, is not public, or is not void.");
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}
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/* Find the listener methods. */
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Method[] methods;
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try {
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methods = ClassHelper.getAllMethods(listenerType);
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} catch(SecurityException E) {
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throw new IntrospectionException("Security: You cannot access fields in this class.");
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}
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Vector chosenMethods = new Vector();
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boolean[] listenerMethodFound = new boolean[listenerMethodNames.length];
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for(int i=0;i<methods.length;i++) {
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if(Modifier.isPrivate(methods[i].getModifiers())) {
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continue;
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}
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Method currentMethod = methods[i];
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Class retval = currentMethod.getReturnType();
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if(retval.equals(java.lang.Void.TYPE)) {
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for(int j=0;j<listenerMethodNames.length;j++) {
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if(currentMethod.getName().equals(listenerMethodNames[j])
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&& (absurdEventClassCheckName == null
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|| (currentMethod.getParameterTypes().length == 1
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&& ((currentMethod.getParameterTypes()[0]).getName().equals(absurdEventClassCheckName)
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|| (currentMethod.getParameterTypes()[0]).getName().endsWith("."+absurdEventClassCheckName)
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)
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)
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)
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) {
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chosenMethods.addElement(currentMethod);
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listenerMethodFound[j] = true;
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}
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}
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}
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}
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/* Make sure we found all the methods we were looking for. */
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for(int i=0;i<listenerMethodFound.length;i++) {
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if(!listenerMethodFound[i]) {
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throw new IntrospectionException("Could not find event method " + listenerMethodNames[i]);
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}
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}
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/* Now that we've chosen the listener methods we want, store them. */
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this.listenerMethods = new Method[chosenMethods.size()];
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for(int i=0;i<chosenMethods.size();i++) {
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this.listenerMethods[i] = (Method)chosenMethods.elementAt(i);
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}
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}
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}
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