org.geotools.data.shapefile.dbf

Class DbaseFileHeader

Object

DbaseFileHeader

public class DbaseFileHeader
extends Object

Class to represent the header of a Dbase III file. Creation date: (5/15/2001 5:15:30 PM)

Field Summary

Fields

Modifier and Type

Field and Description

static long

MILLIS_SINCE_4713 Returns the number of millis at January 1st 4713 BC Calendar refCal = (Calendar) new GregorianCalendar(TimeZone.getTimeZone("UTC")); refCal.set(Calendar.ERA, GregorianCalendar.BC); refCal.set(Calendar.YEAR, 4713); refCal.set(Calendar.MONTH, Calendar.JANUARY); refCal.set(Calendar.DAY_OF_MONTH, 1); refCal.set(Calendar.HOUR, 12); refCal.set(Calendar.MINUTE, 0); refCal.set(Calendar.SECOND, 0); refCal.set(Calendar.MILLISECOND, 0); MILLIS_SINCE_4713 = refCal.getTimeInMillis() - 43200000L; //(43200000L: 12 hour correction factor taken from DBFViewer2000)

Constructor Summary

Constructors

Constructor and Description
DbaseFileHeader()
DbaseFileHeader(Charset charset)

Method Summary

Modifier and Type	Method and Description
void	addColumn(String inFieldName, char inFieldType, int inFieldLength, int inDecimalCount) Add a column to this DbaseFileHeader.
Class<?>	getFieldClass(int i) Determine the most appropriate Java Class for representing the data in the field.
int	getFieldDecimalCount(int inIndex) Get the decimal count of this field.
int	getFieldLength(int inIndex) Returns the field length in bytes.
String	getFieldName(int inIndex) Get the field name.
char	getFieldType(int inIndex) Get the character class of the field.
int	getHeaderLength() Get the length of the header
int	getLargestFieldSize() Get the largest field size of this table.
Date	getLastUpdateDate() Get the date this file was last updated.
long	getLengthForRecords(int records) Returns the expected file size for the given number of records in the file
int	getNumFields() Return the number of fields in the records.
int	getNumRecords() Return the number of records in the file
int	getRecordLength() Get the length of the records in bytes.
void	readHeader(ByteBuffer in) Read the header data from the DBF file.
void	readHeader(ReadableByteChannel channel) Read the header data from the DBF file.
int	removeColumn(String inFieldName) Remove a column from this DbaseFileHeader.
void	setNumRecords(int inNumRecords) Set the number of records in the file
String	toString() Get a simple representation of this header.
void	writeHeader(WritableByteChannel out) Write the header data to the DBF file.

Methods inherited from class Object

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

Field Detail

MILLIS_SINCE_4713

public static long MILLIS_SINCE_4713

Returns the number of millis at January 1st 4713 BC

Calendar refCal = (Calendar) new GregorianCalendar(TimeZone.getTimeZone("UTC")); refCal.set(Calendar.ERA, GregorianCalendar.BC); refCal.set(Calendar.YEAR, 4713); refCal.set(Calendar.MONTH, Calendar.JANUARY); refCal.set(Calendar.DAY_OF_MONTH, 1); refCal.set(Calendar.HOUR, 12); refCal.set(Calendar.MINUTE, 0); refCal.set(Calendar.SECOND, 0); refCal.set(Calendar.MILLISECOND, 0); MILLIS_SINCE_4713 = refCal.getTimeInMillis() - 43200000L; //(43200000L: 12 hour correction factor taken from DBFViewer2000)

Constructor Detail

DbaseFileHeader

public DbaseFileHeader()

DbaseFileHeader

public DbaseFileHeader(Charset charset)

Method Detail

getFieldClass

public Class<?> getFieldClass(int i)

Determine the most appropriate Java Class for representing the data in the field.

 All packages are java.lang unless otherwise specified.
 C (Character) -> String
 N (Numeric)   -> Integer or Long or Double (depends on field's decimal count and fieldLength)
 F (Floating)  -> Double
 L (Logical)   -> Boolean
 D (Date)      -> java.util.Date (Without time)

Parameters:

i - The index of the field, from 0 to getNumFields() - 1 .

Returns:

A Class which closely represents the dbase field type.

addColumn

public void addColumn(String inFieldName,
                      char inFieldType,
                      int inFieldLength,
                      int inDecimalCount)
               throws DbaseFileException

Add a column to this DbaseFileHeader. The type is one of (C N L or D) character, number, logical(true/false), or date. The Field length is the total length in bytes reserved for this column. The decimal count only applies to numbers(N), and floating point values (F), and refers to the number of characters to reserve after the decimal point. Don't expect miracles from this...

 Field Type MaxLength
 ---------- ---------
 C          254
 D          8

Parameters:

inFieldName - The name of the new field, must be less than 10 characters or it gets truncated.

inFieldType - A character representing the dBase field, ( see above ). Case insensitive.

inFieldLength - The length of the field, in bytes ( see above )

inDecimalCount - For numeric fields, the number of decimal places to track.

Throws:

DbaseFileException - If the type is not recognized.

removeColumn

public int removeColumn(String inFieldName)

Remove a column from this DbaseFileHeader.

Parameters:

inFieldName - The name of the field, will ignore case and trim.

Returns:

index of the removed column, -1 if no found

getFieldLength

public int getFieldLength(int inIndex)

Returns the field length in bytes.

Parameters:

inIndex - The field index.

Returns:

The length in bytes.

getFieldDecimalCount

public int getFieldDecimalCount(int inIndex)

Get the decimal count of this field.

Parameters:

inIndex - The field index.

Returns:

The decimal count.

getFieldName

public String getFieldName(int inIndex)

Get the field name.

Parameters:

inIndex - The field index.

Returns:

The name of the field.

getFieldType

public char getFieldType(int inIndex)

Get the character class of the field.

Parameters:

inIndex - The field index.

Returns:

The dbase character representing this field.

getLastUpdateDate

public Date getLastUpdateDate()

Get the date this file was last updated.

Returns:

The Date last modified.

getNumFields

public int getNumFields()

Return the number of fields in the records.

Returns:

The number of fields in this table.

getNumRecords

public int getNumRecords()

Return the number of records in the file

Returns:

The number of records in this table.

getRecordLength

public int getRecordLength()

Get the length of the records in bytes.

Returns:

The number of bytes per record.

getHeaderLength

public int getHeaderLength()

Get the length of the header

Returns:

The length of the header in bytes.

readHeader

public void readHeader(ReadableByteChannel channel)
                throws IOException

Read the header data from the DBF file.

Parameters:

channel - A readable byte channel. If you have an InputStream you need to use, you can call java.nio.Channels.getChannel(InputStream in).

Throws:

IOException - If errors occur while reading.

readHeader

public void readHeader(ByteBuffer in)
                throws IOException

Read the header data from the DBF file.

Parameters:

in - The ByteBuffer to read the header from

Throws:

IOException - If errors occur while reading.

getLargestFieldSize

public int getLargestFieldSize()

Get the largest field size of this table.

Returns:

The largest field size in bytes.

setNumRecords

public void setNumRecords(int inNumRecords)

Set the number of records in the file

Parameters:

inNumRecords - The number of records.

writeHeader

public void writeHeader(WritableByteChannel out)
                 throws IOException

Write the header data to the DBF file.

Parameters:

out - A channel to write to. If you have an OutputStream you can obtain the correct channel by using java.nio.Channels.newChannel(OutputStream out).

Throws:

IOException - If errors occur.

toString

public String toString()

Get a simple representation of this header.

Overrides:

toString in class Object

Returns:

A String representing the state of the header.

getLengthForRecords

public long getLengthForRecords(int records)

Returns the expected file size for the given number of records in the file