"

 COPYRIGHT (c) 2001 by eXept Software AG

              All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

"{ Package: 'stx:libbasic' }"

ProceedableError subclass:#MessageNotUnderstood

	instanceVariableNames:''

	classVariableNames:''

	poolDictionaries:''

	category:'Kernel-Exceptions-Errors'

!

!MessageNotUnderstood class methodsFor:'documentation'!

copyright

"

 COPYRIGHT (c) 2001 by eXept Software AG

              All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

!

documentation

"

    raised when a message is sent to an object, which is not understood

    by the receiver, and the message was not handled by a class specific

    doesNotUnderstand: handler.

"

! !

!MessageNotUnderstood class methodsFor:'save evaluation'!

ignoreNotUnderstoodOf:aSelector in:aBlock

    "evaluate aBlock; if a messageNotUnderstood occurs,

     for which the message was aSelector, ignore the error

     and return.

     Other selector errors lead into the debugger.

     If no error occurs, return the blocks value"

    ^ self handle:[:ex |

        ex selector == aSelector ifFalse:[

            ex reject

        ]

    ] do:aBlock.

!

ignoreNotUnderstoodOfAny:aCollectionOfSelectors in:aBlock

    "evaluate aBlock; if a messageNotUnderstood occurs,

     for which the message was any in aCollectionOfSelectors, ignore the error

     and return.

     Other selector errors lead into the debugger.

     If no error occurs, return the blocks value"

    ^ self handle:[:ex |

        (aCollectionOfSelectors includesIdentical:ex selector) ifFalse:[

            ex reject

        ]

    ] do:aBlock.

! !

!MessageNotUnderstood methodsFor:'accessing'!

message

    ^ parameter

    "

     [

        123 perform:#foo

     ] on:MessageNotUnderstood do:[:ex |

        Transcript show:'message object: '; showCR:ex message storeString.

        Transcript show:'receiver: '; showCR:ex receiver storeString.

        Transcript show:'selector: '; showCR:ex message selector storeString.

        Transcript show:'arguments: '; showCR:ex message arguments storeString.

     ]

    "

!

receiver

    ^ originator

    "

     [

        123 perform:#foo

     ] on:MessageNotUnderstood do:[:ex |

        Transcript showCR:ex receiver

     ]

    "

!

selector

    ^ parameter selector

    "

     [

        123 perform:#foo

     ] on:MessageNotUnderstood do:[:ex |

        Transcript show:'selector: '; showCR:ex selector storeString.

     ]

    "

! !

!MessageNotUnderstood methodsFor:'printing & storing'!

description

    "the human readable description of the exception"

    |cls sel description|

    "extract the class that should have implemented the message.

     (in case of a super-send, this is not the receivers class)"

    cls isNil ifTrue:[

        cls := self receiver 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)"

        description := cls displayString.

    ] ifFalse:[    

        description := '(** nil-class **)'

    ].

    sel := self selector.

    sel class == Symbol ifTrue:[

        description := description , ' does not understand: #' , sel.

        "/ description := sel, ' not understood by ' ,  description.

    ] ifFalse:[

        "a non-symbol selector may happen when things go mad in a primitive, 

         or a method has been called by #perform: or #valueWithReceiver: with a wrong arg."

        description := description , ' does not understand nonSymbol: ' , sel printString.

        "/ description := sel printString, ' (nonSymbol) not understood by ' ,  description.

    ].

    ^ description

    "

        2 foo:3

        2 perform:55

        nil // 2

    "

! !

!MessageNotUnderstood class methodsFor:'documentation'!

version

! !