Class: ObjectCoder

• Inheritance
• Description
• Class protocol
  • encoding / decoding
  • instance creation
• Instance protocol
  • accessing
  • decoding
  • encoding
  • encoding-smalltalk types
  • initialization
  • private-accessing

Inheritance:

   Object
   |
   +--Visitor
      |
      +--AspectVisitor
         |
         +--ObjectCoder
            |
            +--BaseNCoder
            |
            +--JSONPrinter
            |
            +--XMLCoder

Package:

stx:libbasic

Category:

System-Storage

Version:

rev: 1.33 date: 2024/03/19 12:07:49

user: cg

file: ObjectCoder.st directory: libbasic

module: stx stc-classLibrary: libbasic

Description:

This is an abstract class. Subclasses implement encoding and decoding
of Objects onto resp. from a stream. Possible coders are ASN.1/BER,
CORBA/CDR, BOSS, RMI ...

Classes which implement basic types (Boolean, Integer, Float, ...)
implement the visitor methods #acceptVisitor:with:, which dispatches onto an ObjectCoder.



[instance variables:]
    stream  <Stream>        the stream we read/write the encodings from/to

[class variables:]

copyright
COPYRIGHT (c) 2000 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.

Class protocol:

 decode: aByteArrayOrString

decode aByteArrayOrString

Usage example(s):

Base64Coder encode:#[1 2 16rFe 16rFF] Base64Coder decode:'AQL+/w==' (Base64Coder decode:(Base64Coder encode:#[1 2 16rFe 16rFF])) = #[1 2 16rFe 16rFF]

 decodingOf: anObject

use decode

** This is an obsolete interface - do not use it (it may vanish in future versions) **

 encode: anObject

encode anObject.
Some subclasses (eg. XMLCoder) allow arbitrary objects to be encoded/decoded,
others don't (eg. Base64Coder)

Usage example(s):

Base64Coder encode:#[1 2 16rFe 16rFF] Base64Coder encode:'hello' OSI::BERCoder encode:'hello'

 encode: anObject on: aStream

encode anObject onto a stream
Some subclasses (eg. XMLCoder) allow arbitrary objects to be encoded/decoded,
others don't (eg. Base64Coder)

 encode: anObject on: aStream with: info

encode anObject onto a stream
Some subclasses (eg. XMLCoder) allow arbitrary objects to be encoded/decoded,
others don't (eg. Base64Coder)

 encode: anObject with: aParameter

encode anObject onto a stream
Some subclasses (eg. XMLCoder) allow arbitrary objects to be encoded/decoded,
others don't (eg. Base64Coder)

 encodingOf: anObject

use #encode:

** This is an obsolete interface - do not use it (it may vanish in future versions) **

 encodingOf: anObject with: aParameter

use #encode:with:

** This is an obsolete interface - do not use it (it may vanish in future versions) **

 on: aStream

return an encoder/decoder for a stream

Instance protocol:

 contents

 next

read, decode and return the next object

** This method must be redefined in concrete classes (subclassResponsibility) **

 encode: anObject

 encode: anObject on: aStream

 encode: anObject on: aStream with: info

 encodingOf: anObject

answer the encoded argument anObject

 encodingOf: anObject with: aParameter

answer the encoded argument anObject

 endEncoding

redefinable - allows subclass to create a file trailer or similar stuff

 nextPut: anObject

encode anObject onto my stream.
Anser anObject

 nextPut: anObject with: aParameter

encode anObject onto my stream

 nextPutAll: aCollectionOfObjects

encode all objects from the argument.
Answer the receiver

 startEncoding

redefinable - allows subclass to create a file header or similar stuff

 visitBlock: aBlock with: aParameter

encoding of blocks is rather difficult and an error by default.
If a concrete encoder supports this, redefine it there

 close

close the underlying stream

 emptyWriteStream

answer an empty stream for writing the encoded object

** This method must be redefined in concrete classes (subclassResponsibility) **

 flush

flush possibly internally buffered data.
Nothing is done by default. Subclasses may redefine this

 reset

reset the coder

 stream

return my input or output stream

 stream: aStream

set my input or output stream