com.bbn.openmap.dataAccess.iso8211
Class DDFField

java.lang.Object
  com.bbn.openmap.dataAccess.iso8211.DDFField

public class DDFField
extends java.lang.Object

This object represents one field in a DDFRecord. This models an instance of the fields data, rather than it's data definition which is handled by the DDFFieldDefn class. Note that a DDFField doesn't have DDFSubfield children as you would expect. To extract subfield values use GetSubfieldData() to find the right data pointer and then use ExtractIntData(), ExtractFloatData() or ExtractStringData().

Field Summary

protected int	dataLength
protected int	dataPosition
protected int	headerOffset
protected byte[]	pachData
protected DDFFieldDefinition	poDefn
protected java.util.Hashtable	subfields

Constructor Summary

DDFField()

DDFField(DDFFieldDefinition poDefnIn, byte[] pachDataIn)

DDFField(DDFFieldDefinition poDefnIn, byte[] pachDataIn, boolean doSubfields)

DDFField(DDFFieldDefinition poDefnIn, int dataPositionIn, int dataLengthIn)

Method Summary

protected void	addSubfield(DDFSubfield ddfs)
void	buildSubfields()
byte[]	getData() Return the pointer to the entire data block for this record.
int	getDataLength() If getData() returns null, it'll be your responsibilty to go after the data you need for this field.
int	getDataPosition() If getData() returns null, it'll be your responsibilty to go after the data you need for this field.
int	getDataSize() Return the number of bytes in the data block returned by GetData().
DDFFieldDefinition	getFieldDefn() Fetch the corresponding DDFFieldDefn.
int	getHeaderOffset() Get how many bytes to add to the data position for absolute position in the data file for the field data.
int	getRepeatCount() How many times do the subfields of this record repeat? This will always be one for non-repeating fields.
DDFSubfield	getSubfield(java.lang.String subfieldName) Will return a DDFSubfield object with the given name, or the first one off the list for a repeating subfield.
byte[]	getSubfieldData(DDFSubfieldDefinition poSFDefn, MutableInt pnMaxBytes, int iSubfieldIndex) Fetch raw data pointer for a particular subfield of this field.
java.util.List	getSubfields(java.lang.String subfieldName) Will return an ordered list of DDFSubfield objects.
void	initialize(DDFFieldDefinition poDefnIn, byte[] pachDataIn)
protected void	setHeaderOffset(int headerOffsetIn) Set how many bytes to add to the data position for absolute position in the data file for the field data.
java.lang.String	toString() Creates a string with variety of information about this field, and all it's subfields is written to the given debugging file handle.

Methods inherited from class java.lang.Object

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

Field Detail

poDefn

protected DDFFieldDefinition poDefn

pachData

protected byte[] pachData

subfields

protected java.util.Hashtable subfields

dataPosition

protected int dataPosition

dataLength

protected int dataLength

headerOffset

protected int headerOffset

Constructor Detail

DDFField

public DDFField()

DDFField

public DDFField(DDFFieldDefinition poDefnIn,
                int dataPositionIn,
                int dataLengthIn)

DDFField

public DDFField(DDFFieldDefinition poDefnIn,
                byte[] pachDataIn)

DDFField

public DDFField(DDFFieldDefinition poDefnIn,
                byte[] pachDataIn,
                boolean doSubfields)

Method Detail

initialize

public void initialize(DDFFieldDefinition poDefnIn,
                       byte[] pachDataIn)

setHeaderOffset

protected void setHeaderOffset(int headerOffsetIn)

Set how many bytes to add to the data position for absolute position in the data file for the field data.

getHeaderOffset

public int getHeaderOffset()

Get how many bytes to add to the data position for absolute position in the data file for the field data.

getData

public byte[] getData()

Return the pointer to the entire data block for this record. This is an internal copy, and shouldn't be freed by the application. If null, then check the dataPosition and daataLength for byte offsets for the data in the file, and go get it yourself. This is done for really large files where it doesn't make sense to load the data.

getDataSize

public int getDataSize()

Return the number of bytes in the data block returned by GetData().

getFieldDefn

public DDFFieldDefinition getFieldDefn()

Fetch the corresponding DDFFieldDefn.

getDataPosition

public int getDataPosition()

If getData() returns null, it'll be your responsibilty to go after the data you need for this field.

Returns:

the byte offset into the source file to start reading this field.

getDataLength

public int getDataLength()

If getData() returns null, it'll be your responsibilty to go after the data you need for this field.

Returns:

the number of bytes contained in the source file for this field.

toString

public java.lang.String toString()

Creates a string with variety of information about this field, and all it's subfields is written to the given debugging file handle. Note that field definition information (ala DDFFieldDefn) isn't written.

Overrides:

toString in class java.lang.Object

Returns:

String containing info.

getSubfields

public java.util.List getSubfields(java.lang.String subfieldName)

Will return an ordered list of DDFSubfield objects. If the subfield wasn't repeated, it will provide a list containing one object. Will return null if the subfield doesn't exist.

getSubfield

public DDFSubfield getSubfield(java.lang.String subfieldName)

Will return a DDFSubfield object with the given name, or the first one off the list for a repeating subfield. Will return null if the subfield doesn't exist.

getSubfieldData

public byte[] getSubfieldData(DDFSubfieldDefinition poSFDefn,
                              MutableInt pnMaxBytes,
                              int iSubfieldIndex)

Fetch raw data pointer for a particular subfield of this field. The passed DDFSubfieldDefn (poSFDefn) should be acquired from the DDFFieldDefn corresponding with this field. This is normally done once before reading any records. This method involves a series of calls to DDFSubfield::GetDataLength() in order to track through the DDFField data to that belonging to the requested subfield. This can be relatively expensive.

Parameters:

poSFDefn - The definition of the subfield for which the raw data pointer is desired.

pnMaxBytes - The maximum number of bytes that can be accessed from the returned data pointer is placed in this int, unless it is null.

iSubfieldIndex - The instance of this subfield to fetch. Use zero (the default) for the first instance.

Returns:

A pointer into the DDFField's data that belongs to the subfield. This returned pointer is invalidated by the next record read (DDFRecord::ReadRecord()) and the returned pointer should not be freed by the application.

buildSubfields

public void buildSubfields()

addSubfield

protected void addSubfield(DDFSubfield ddfs)

getRepeatCount

public int getRepeatCount()

How many times do the subfields of this record repeat? This will always be one for non-repeating fields.

Returns:

The number of times that the subfields of this record occur in this record. This will be one for non-repeating fields.