Use the Java reflection mechanism to obtain a list of all the events that can be added to the interface class.

When writing Java code, we need to add listening events to the event source, but we often cannot remember the events that can be used by this event source. Therefore, I refer to Java programming ideas, according to the instructions in the book, the following code is written to obtain a list of events that can be used by the event source.

The program running interface is as follows:

This program is still a bit imperfect. The input class name must be case-sensitive. In addition, the program runs in Java applet.

The main code is as follows:

 

Package niutool;
Import niutool. Console;
Import javax. Swing .*;
Import javax. Swing. event .*;
Import java. AWT .*;
Import java. AWT. event .*;
Import java. Lang. Reflect .*;
Import java. util. RegEx .*;

Public class showaddlisteners extends japplet {
Private jtextfield name = new jtextfield (25 );
Private jtextarea Results = new jtextarea (40, 65 );
Private Static pattern addlistener =
Pattern. Compile ("(Add/W +? Listener /(.*? /))");
Private Static pattern qualifier =
Pattern. Compile ("/W + /.");
Class namel implements actionlistener {
Public void actionreceivmed (actionevent e ){
String Nm = Name. gettext (). Trim ();
If (nm. Length () = 0 ){
Results. settext ("no matching ");
Return;
}
Class Klass;
Try {
Klass = Class. forname ("javax. Swing." + nm );
} Catch (classnotfoundexception ex ){
Results. settext ("no matching ");
Return;
}
Method [] Methods = Klass. getmethods ();
Results. settext ("");
For (INT I = 0; I <methods. length; I ++ ){
Matcher =
Addlistener. matcher (methods [I]. tostring ());
If (matcher. Find ())
Results. append (qualifier. matcher (
Matcher. Group (1). replaceall ("") + "");
}
}
}
Public void Init (){
Namel namelistener = new namel ();
Name. addactionlistener (namelistener );
Jpanel Top = new jpanel ();
Top. Add (New jlabel ("swing class name (Press ENTER ):"));
Top. Add (name );
Container CP = getcontentpane ();
CP. Add (borderlayout. North, top );
CP. Add (New jscrollpane (results ));
// Initial data and test:
Name. settext ("jtextarea ");
Namelistener. actionreceivmed (
New actionevent ("", 0 ,""));
}
Public static void main (string [] ARGs ){
Console. Run (New showaddlisteners (), 500,400 );
}
}///:~

Import niutool. console and introduce a console tool. The source code is as follows:

 

Package niutool;
Import javax. Swing .*;
Import java. AWT. event .*;
Public class console {
// Create a title string from the class name:
Public static String title (Object O ){
String T = O. getclass (). tostring ();
// Remove the word "class ":
If (T. indexof ("class ")! =-1)
T = T. substring (6 );
Return T;
}
Public static void
Run (jframe frame, int width, int height ){
Frame. setdefaclocloseoperation (jframe. exit_on_close );
Frame. setsize (width, height );
Frame. setvisible (true );
}
Public static void
Run (japplet applet, int width, int height ){
Jframe frame = new jframe (title (applet ));
Frame. setdefaclocloseoperation (jframe. exit_on_close );
Frame. getcontentpane (). Add (applet );
Frame. setsize (width, height );
Applet. INIT ();
Applet. Start ();
Frame. setvisible (true );
}
Public static void
Run (jpanel, int width, int height ){
Jframe frame = new jframe (title (panel ));
Frame. setdefaclocloseoperation (jframe. exit_on_close );
Frame. getcontentpane (). Add (panel );
Frame. setsize (width, height );
Frame. setvisible (true );
}
}///:~

There is something you don't understand. You can look at Java programming ideas.