com.bbn.openmap.dataAccess.iso8211
Class DDFModule

java.lang.Object
  |
  +--com.bbn.openmap.dataAccess.iso8211.DDFModule

All Implemented Interfaces:

DDFConstants

public class DDFModule

extends java.lang.Object

implements DDFConstants

The class that represents a ISO 8211 file.

Field Summary

protected byte	_appIndicator
protected java.lang.String	_extendedCharSet
protected int	_fieldAreaStart
protected int	_fieldControlLength
protected byte	_inlineCodeExtensionIndicator
protected byte	_interchangeLevel
protected byte	_leaderIden
protected int	_recLength
protected int	_sizeFieldLength
protected int	_sizeFieldPos
protected int	_sizeFieldTag
protected byte	_versionNumber
protected java.lang.String	fileName
protected BinaryFile	fpDDF
protected long	nFirstRecordOffset
protected java.util.Vector	paoFieldDefns
protected DDFRecord	poRecord

Fields inherited from interface com.bbn.openmap.dataAccess.iso8211.DDFConstants

DDF_FIELD_TERMINATOR, DDF_LEADER_SIZE, DDF_UNIT_TERMINATOR

Constructor Summary

DDFModule()
The constructor.

DDFModule(java.lang.String ddfName)

Method Summary

void	close() Close an ISO 8211 file.
void	destroy() Clean up, get rid of data and close file pointer.
java.lang.String	dump()
DDFFieldDefinition	findFieldDefn(java.lang.String pszFieldName) Fetch the definition of the named field.
DDFFieldDefinition	getField(int i) Fetch a field definition by index.
BinaryFile	open(java.lang.String pszFilename) Open a ISO 8211 (DDF) file for reading, and read the DDR record to build the field definitions.
int	read() Convenience method to read a byte from the data file.
int	read(byte[] toData, int offset, int length) Method for other components to call to get the DDFModule to read bytes into the provided array.
DDFRecord	readRecord() Read one record from the file, and return to the application.
void	reopen()
void	rewind(long nOffset) Return to first record.
void	seek(long pos) Convenience method to seek to a location in the data file.
java.lang.String	toString() Write out module info to debugging file.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

fpDDF

protected BinaryFile fpDDF

fileName

protected java.lang.String fileName

nFirstRecordOffset

protected long nFirstRecordOffset

_interchangeLevel

protected byte _interchangeLevel

_inlineCodeExtensionIndicator

protected byte _inlineCodeExtensionIndicator

_versionNumber

protected byte _versionNumber

_appIndicator

protected byte _appIndicator

_fieldControlLength

protected int _fieldControlLength

_extendedCharSet

protected java.lang.String _extendedCharSet

_recLength

protected int _recLength

_leaderIden

protected byte _leaderIden

_fieldAreaStart

protected int _fieldAreaStart

_sizeFieldLength

protected int _sizeFieldLength

_sizeFieldPos

protected int _sizeFieldPos

_sizeFieldTag

protected int _sizeFieldTag

paoFieldDefns

protected java.util.Vector paoFieldDefns

poRecord

protected DDFRecord poRecord

Constructor Detail

DDFModule

public DDFModule()

The constructor. Need to call open() if this constuctor is used.

DDFModule

public DDFModule(java.lang.String ddfName)
          throws java.io.IOException

Method Detail

close

public void close()

Close an ISO 8211 file. Just close the file pointer to the file.

destroy

public void destroy()

Clean up, get rid of data and close file pointer.

open

public BinaryFile open(java.lang.String pszFilename)
                throws java.io.IOException

Open a ISO 8211 (DDF) file for reading, and read the DDR record to build the field definitions. If the open succeeds the data descriptive record (DDR) will have been read, and all the field and subfield definitions will be available.

Parameters:

pszFilename - The name of the file to open.

java.io.IOException

toString

public java.lang.String toString()

Write out module info to debugging file. A variety of information about the module is written to the debugging file. This includes all the field and subfield definitions read from the header.

Overrides:

toString in class java.lang.Object

dump

public java.lang.String dump()

findFieldDefn

public DDFFieldDefinition findFieldDefn(java.lang.String pszFieldName)

Fetch the definition of the named field. This function will scan the DDFFieldDefn's on this module, to find one with the indicated field name.

Parameters:

pszFieldName - The name of the field to search for. The comparison is case insensitive.

Returns:

A pointer to the request DDFFieldDefn object is returned, or null if none matching the name are found. The return object remains owned by the DDFModule, and should not be deleted by application code.

readRecord

public DDFRecord readRecord()

Read one record from the file, and return to the application. The returned record is owned by the module, and is reused from call to call in order to preserve headers when they aren't being re-read from record to record.

Returns:

A pointer to a DDFRecord object is returned, or null if a read error, or end of file occurs. The returned record is owned by the module, and should not be deleted by the application. The record is only valid untill the next ReadRecord() at which point it is overwritten.

read

public int read(byte[] toData,
                int offset,
                int length)

Method for other components to call to get the DDFModule to read bytes into the provided array.

Parameters:

toData - the bytes to put data into.

offset - the byte offset to start reading from, whereever the pointer currently is.

length - the number of bytes to read.

Returns:

the number of bytes read.

read

public int read()

Convenience method to read a byte from the data file. Assumes that you know what you are doing based on the parameters read in the data file. For DDFFields that haven't loaded their subfields.

seek

public void seek(long pos)
          throws java.io.IOException

Convenience method to seek to a location in the data file. Assumes that you know what you are doing based on the parameters read in the data file. For DDFFields that haven't loaded their subfields.

Parameters:

pos - the byte position to reposition the file pointer to.

java.io.IOException

getField

public DDFFieldDefinition getField(int i)

Fetch a field definition by index.

Parameters:

i - (from 0 to GetFieldCount() - 1.

Returns:

the returned field pointer or null if the index is out of range.

rewind

public void rewind(long nOffset)
            throws java.io.IOException

Return to first record. The next call to ReadRecord() will read the first data record in the file.

Parameters:

nOffset - the offset in the file to return to. By default this is -1, a special value indicating that reading should return to the first data record. Otherwise it is an absolute byte offset in the file.

java.io.IOException

reopen

public void reopen()