isCOBOL Evolve : SDK User's Guide : Files Management : File Handlers
File Handlers
The isCOBOL Framework includes a series of file handlers that allows you to manage sequential, relative and indexed files. These file handlers are implemented by dedicated classes in the package com.iscobol.io. For most of them, an alias is provided in order to easily reference the file handler without specifying the full class name. The table below lists the available file handlers providing class name, alias and a brief description:
Indexed file handlers
Class-Name
Alias
Description
com.iscobol.extfh.ExtfhIndex
n/a
The file is handled by the 32bit EXTFH interface.
com.iscobol.extfh3.ExtfhIndex
n/a
The file is handled by the 64bit EXTFH interface.
com.iscobol.io.DynamicBtrieve
btrieve
The file is handled by the Btrieve interface.
com.iscobol.io.DynamicConnector
fscsc
The file is handled by c-tree through FileConnector.
com.iscobol.io.DynamicCtree
ctree
The file is handled by c-tree of version 9.5.51961 or previous.
com.iscobol.io.DynamicCtree2
ctree2
The file is handled by c-tree of version 9.5.53702 or later.
com.iscobol.io.DynamicCtreeJ
ctreej
The file is handled by c-tree of version 10.4.0.39701 or later through a Java interface. Note that the native client library is always required.
com.iscobol.io.DynamicDCI
dci
The file is handled by the DBMaker DCI interface.
com.iscobol.io.DynamicDConnector
dcic
The file is handled by the DCI File Connector.
com.iscobol.io.DynamicEasyDB
easydb
The file is handled by isCOBOL DatabaseBridge.
com.iscobol.io.DynamicJIsam
jisam
The file is a JIsam archivie (default).
com.iscobol.io.DynamicMConnector
mfc
The file is handled by the Micro Focus File Connector.
com.iscobol.io.DynamicRConnector
rmc
The file is handled by the RM/COBOL File Connector.
com.iscobol.io.DynamicRemote
remote
The file is handled remotely by the file server feature provided by isCOBOL Server.
com.iscobol.io.DynamicVConnector
vfc
The file is handled by the Vision File Connector.
com.iscobol.io.DynamicVision
vision
The file is handled by the Acucobol-GT Vision interface. The runcbl library, provided separately, is required.
com.iscobol.io.ScanMF
n/a
The file is handled by an internal Micro Focus files interface. You can only sequentially read next in input mode, other i-o is not supported. Micro Focus formats 1, 2, 3, 4 and 8 as well as C-ISAM are supported. Compressed files and split files are not supported, they won't be opened by the ScanMF class. A parsing error may occur while reading files with variable length records if the area of a record was reused by the MF runtime, e.g. due to a REWRITE statement or because it overwrote the area of a deleted record in order to save space.
com.iscobol.io.ScanRMKF
n/a
The file is handled by an internal RM/COBOL files interface. You can only sequentially read next in input mode, other i-o is not supported.
com.iscobol.io.ScanVision
n/a
The file is handled by an internal Vision interface. You can only sequentially read next, other i-o is not supported. Vision formats 3 to 6 are supported.
 
The following file types are currently not supported:
- encrypted files
- Vision files version 1 and 2
A 9D error is returned on open of unsupported files.
Binary Sequential file handlers
Class-Name
Alias
Effect
com.iscobol.extfh.ExtfhSequential
n/a
The sequential file is handled by the 32bit EXTFH interface.
com.iscobol.extfh3.ExtfhSequential
n/a
The sequential file is handled by the 64bit EXTFH interface.
com.iscobol.io.DynamicEasyDBSeq
easydb
The file is handled by isCOBOL DatabaseBridge.
com.iscobol.io.DynamicMFSequential
mfsequential
The file is handled in compatibility with Micro Focus.
com.iscobol.io.DynamicRemote
remote
The file is handled remotely by the file server feature provided by isCOBOL Server.
com.iscobol.io.DynamicSeqACU
seqacu
The fixed length sequential file is handled in compatibility with Acucobol.
com.iscobol.io.DynamicSequential
sequential
The file is a binary file on the local machine (default).
com.iscobol.io.DynamicVarSeqACU
varseqacu
The variable length sequential file is handled in compatibility with Acucobol.
com.iscobol.io.RemoteRelative
remote
The file is a binary file on the client machine (Application Server).
Relative file handlers
Class-Name
Alias
Effect
com.iscobol.extfh.ExtfhRelative
n/a
The relative file is handled by the 32bit EXTFH interface.
com.iscobol.extfh3.ExtfhRelative
n/a
The relative file is handled by the 64bit EXTFH interface.
com.iscobol.io.DynamicEasyDBRel
easydb
The file is handled by isCOBOL DatabaseBridge.
com.iscobol.io.DynamicRelative
relative
The file is a binary file on the local machine (default).
com.iscobol.io.DynamicRemote
remote
The file is handled remotely by the file server feature provided by isCOBOL Server.
Line Sequential file handlers
Class-Name
Alias
Effect
com.iscobol.extfh.ExtfhLineSequential
n/a
The file is handled by the 32bit EXTFH interface.
com.iscobol.extfh3.ExtfhLineSequential
n/a
The file is handled by the 64bit EXTFH interface.
com.iscobol.io.DynamicEasyDBLSeq
easydb
The file is handled by isCOBOL DatabaseBridge.
com.iscobol.io.DynamicLSeq8bit
lseq8bit
The file is handled by the standard isCOBOL interface (default).
com.iscobol.io.DynamicLSeqACU
lseqacu
The file is handled by an Acucobol compatible interface that discards form feed, carriage return and line feed before returning the record.
com.iscobol.io.DynamicLSeqMF_N
lseqmf_n
The file is handled by a Micro Focus compatible interface that doesn’t treat 0x0A in COMP fields as line feed.
com.iscobol.io.DynamicRemote
remote
The file is handled remotely by the file server feature provided by isCOBOL Server.
It doesn’t work for stream files and print files.
It doesn’t work if program is compiled with the -flsu option.
It’s also possible to create your own file handler by extending an existing one or by implementing it from scratch. A couple of examples are installed along with isCOBOL under the folder sample/data-access/files-redirect.