"

              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.

"

ReadWriteStream subclass:#ActorStream

       instanceVariableNames:'nextPutBlock nextPutAllBlock nextBlock'

       classVariableNames:''

       poolDictionaries:''

       category:'Streams'

!

ActorStream comment:'

              All Rights Reserved

This class provides a hook for general objects to behave like Streams;

To the outside, ActorStreams behave like streams and respond to the

usual streams messages (i.e. nextPut:).

In the inside, for every nextPut-message, the nextPutBlock is evaluated

with the argument to perform the put; same is true for nextPutAll: and next;

These blocks are to be provided by the user of the ActorStream.

Instance variables:

nextPutBlock    <Block>   the block to evaluate for nextPut:-messages

nextPutAllBlock <Block>   same for nextPutAll:-messages

nextBlock       <Block>   the Block to evaluate for the next element

written winter 89 by claus

'!

!ActorStream class methodsFor:'instance creation'!

new

    "have to re-allow new - it was disabled in Stream"

    ^ self basicNew

! !

!ActorStream methodsFor:'defining actions'!

nextBlock:aBlock

    "define the block to be evaluated for every next-message"

    nextBlock := aBlock

!

nextPutBlock:aBlock

    "define the block to be evaluated for every nextPut-message"

    nextPutBlock := aBlock

!

nextPutAllBlock:aBlock

    "define the block to be evaluated for every nextPutAll-message"

    nextPutAllBlock := aBlock

! !

!ActorStream methodsFor:'accessing-read/write'!

next

    "return the next element from the stream by evaluating the nextBlock"

    nextBlock notNil ifTrue:[

        ^ nextBlock value

    ].

    self error:'action for next is undefined'

!

nextPut:something

    "put something onto the stream by evaluating the nextPutBlock with

     something as argument"

    nextPutBlock notNil ifTrue:[

        ^ nextPutBlock value:something

    ].

    self error:'action for nextPut is undefined'

!

nextPutAll:something

    "put all elements of something onto the stream by evaluating

     the nextPutAllBlock with something as argument"

    nextPutAllBlock notNil ifTrue:[

        ^ nextPutAllBlock value:something

    ].

    super nextPutAll:something

! !