--- a/JavaField.st	Tue Apr 16 13:34:16 1996 +0000
+++ b/JavaField.st	Tue Apr 16 14:44:23 1996 +0000
@@ -6,6 +6,93 @@
 !
 
 
+!JavaField methodsFor:'error handling'!
+
+doesNotUnderstand:aMessage
+    "this message is sent by the runtime system (VM) when
+     a message is not understood by some object (i.e. there
+     is no method for that selector). The original message has
+     been packed into aMessage (i.e. the receiver, selector and
+     any arguments) and the original receiver is then sent the
+     #doesNotUnderstand: message.
+     Here, we raise another signal which usually enters the debugger.
+     You can of course redefine #doesNotUnderstand: in your classes
+     to implement message delegation."
+
+    |sel errorString cls sender|
+
+    "/ handle the case of an error during early startup
+    "/ (output streams not yet initialized)
+    "/
+    Stdout isNil ifTrue:[
+	Smalltalk fatalAbort:'error during init: ' , aMessage selector , ' not understood'.
+    ].
+
+    (sel := aMessage selector) isNil ifTrue:[
+	"/
+	"/ happens when things go mad, or a method has been
+	"/ called by valueWithReceiver: with a wrong receiver
+	"/ to avoud later trouble (when concatenating strings),
+	"/ replace the selector by some (nonNil) string
+	"/
+	sel := '(nil)'
+    ].
+
+    "/
+    "/ extract the class that should have implemented the message.
+    "/ (in case of a super-send, this is not the receivers class)
+    "/
+    sender := thisContext sender.
+    cls := sender searchClass.
+    cls isNil ifTrue:[
+	"it was NOT a super or directed send ..."
+	cls := self class
+    ].
+
+    cls notNil ifTrue:[
+	"/
+	"/ displayString is better than 'cls name',
+	"/ since it appends (obsolete) for outdated classes.
+	"/ (this happens if you send messages to old instances
+	"/  after changing a classes definition)
+	"/
+	errorString := cls displayString.
+    ] ifFalse:[    
+	errorString := '(** nil-class **)'
+    ].
+    errorString := errorString , ' does not understand: ' , sel.
+
+    "/
+    "/ this only happens, when YOU play around with my classvars ...
+    "/ (or an error occurs during early startup, when signals are not yet set)
+    "/
+    MessageNotUnderstoodSignal isNil ifTrue:[
+	^ self enterDebuggerWith:nil
+			 message:'oops - MessageNotUnderstoodSignal is gone'.
+    ].
+
+    "/
+    "/ thats where we end up normally - raise a signal which (if unhandled) opens a debugger
+    "/
+    ^ MessageNotUnderstoodSignal
+		raiseRequestWith:aMessage
+		     errorString:errorString
+			      in:sender
+
+    "Modified: 9.12.1995 / 17:25:37 / cg"
+
+"
+*** WARNING
+***
+*** this method has been automatically created,
+*** since all nil-subclasses should respond to some minimum required
+*** protocol.
+***
+*** Inspection and/or debugging of instances may not be possible,
+*** if you remove/change this method. 
+"
+! !
+
 !JavaField methodsFor:'private accessing'!
 
 setAccessFlags:flags
@@ -32,8 +119,48 @@
     "Created: 16.4.1996 / 13:04:43 / cg"
 ! !
 
+!JavaField methodsFor:'queries'!
+
+class
+    "return the receivers class"
+
+%{  /* NOCONTEXT */
+
+    RETURN ( __Class(self) );
+%}
+
+"
+*** WARNING
+***
+*** this method has been automatically created,
+*** since all nil-subclasses should respond to some minimum required
+*** protocol.
+***
+*** Inspection and/or debugging of instances may not be possible,
+*** if you remove/change this method. 
+"
+!
+
+isBehavior
+    "return true, if the receiver is some kind of class (i.e. behavior);
+     false is returned here - the method is only redefined in Behavior."
+
+    ^ false
+
+"
+*** WARNING
+***
+*** this method has been automatically created,
+*** since all nil-subclasses should respond to some minimum required
+*** protocol.
+***
+*** Inspection and/or debugging of instances may not be possible,
+*** if you remove/change this method. 
+"
+! !
+
 !JavaField class methodsFor:'documentation'!
 
 version
-    ^ '$Header: /home/jv/Projects/SmalltalkX/repositories/cvs/stx/libjava/JavaField.st,v 1.1 1996/04/16 13:33:45 cg Exp $'
+    ^ '$Header: /home/jv/Projects/SmalltalkX/repositories/cvs/stx/libjava/JavaField.st,v 1.2 1996/04/16 14:41:33 cg Exp $'
 ! !