stream class %Library.FileCharacterStream
extends %CharacterStream, %FileStreamAdaptor
Stream class that stores character data in external files.
This class is deprecated in favor of %Stream.FileCharacter.
For example the following code opens a file character stream, points it at a particular file
on the filesystem and then reads it in line by line:
Set stream=##class(%FileCharacterStream).%New()
Set stream.Filename="c:\myfile.txt"
While 'stream.AtEnd {
Set line=stream.ReadLine()
; Process the line here
}
The difference between file character stream and file binary streams is that the character
stream understands that it is writing character data and this may be subject to characterset
translation. For example you may wish to utf-8 encode character data being written to the file,
but with a binary file stream it is just a series of binary data and so this is always read/written
exactly as it is without and translation.
• parameter OPENAPPEND = "AWS";
• parameter OPENREAD = "RU";
• parameter OPENREADTERM = "RS";
• parameter OPENWRITE = "WSN";
• property BOM
as %String [ Transient ];
BOM characters that appear at start of file to signify which encoding it is using
• property StreamFormatWrite
as %Boolean [ InitialExpression = 1,Transient ];
The StreamFormatWrite property controls whether file output is in stream or undefined format.
If StreamFormatWrite is 1 (true), the default, the file is written in S (stream) format.
If StreamFormatWrite is 0 (false), the file is written in U (Undefined) format.
For Unix file output, S format converts crlf to lf which can be a problem for MIME
output such as email. The user can now set messagepart.TextData.StreamFormatWrite=0
to keep crlf in text message parts of the mail message.
• property TranslateTable
as %String [ InitialExpression = "0",Transient ];
The translation table to be used when reading or writing the file.
Initial value of 0 indicates that the table has not yet been set.
A new value for the translation table will not take effect until the next
mode change from read to write or the next rewind.
• method %Oid()
as %ObjectIdentity
Returns the OID of this object.
• method IsFileUnicode()
as %Boolean
Returns true if the file is Unicode.
This method may only be called after data has been read
from the file stream.
• method SizeGet()
as %Integer
Return the current size of the data stream.
Note this is complicated by having to worry about the translate table used to write the file.
VMS does not support moving to a position in a file or providing the current position in a file.
On VMS if a BOM is included at the start of the file it may be included in the size calculated.
• method TranslateTableSet(table As %String)
as %Status
If translation table is set after the file has been opened
then switch the table used for the file.
If the translation table is set to "", then the "RAW" table is used.
