de.fhg.igd.earth.model.input.shapefile
Class ShapeFile

java.lang.Object
  de.fhg.igd.earth.model.input.shapefile.ShapeUtils
      de.fhg.igd.earth.model.input.shapefile.ShapeFile

public class ShapeFile

extends ShapeUtils

Class representing an ESRI Shape File. Title : Earth Copyright : Copyright (c) 2001 Organisation : IGD FhG

Version:

: 1.0

Author:

: Werner Beutel

Field Summary

static int	DEFAULT_RECORD_BUFFER_SIZE A default record size.
protected ESRIBoundingBox	fileBounds Holds the bounds of the file (four doubles).
protected long	fileLength Holds the length of the file, in bytes.
protected int	fileShapeType Holds the shape type of the file.
protected int	fileVersion Holds the version of the file, as an int.
protected byte[]	header The buffer that holds the 100 byte header.
protected RandomAccessFile	raf The read/write class for shape files.
protected byte[]	recBuf A buffer for the current record's data.
protected byte[]	recHdr A buffer for current record's header.
static int	SHAPE_FILE_CODE A Shape File's magic number.
static int	SHAPE_FILE_VERSION The currently handled version of Shape Files.

Fields inherited from class de.fhg.igd.earth.model.input.shapefile.ShapeUtils

SHAPE_FILE_HEADER_LENGTH, SHAPE_FILE_HEADER_LENGTH_DB, SHAPE_FILE_RECORD_HEADER_LENGTH, SHAPE_TYPE_ARC, SHAPE_TYPE_MULTIPOINT, SHAPE_TYPE_NULL, SHAPE_TYPE_POINT, SHAPE_TYPE_POLYGON, SHAPE_TYPE_POLYLINE

Constructor Summary

ShapeFile(File file)
Construct a ShapeFile from the given File.

ShapeFile(String name)
Construct a ShapeFile from a file name.

Method Summary

void	add(ESRIRecord r) Adds a record to the end of this file.
void	close() Closes the shape file and disposes of resources.
ESRIBoundingBox	getBoundingBox() Returns the bounding box of this shape file.
long	getFileLength() Returns the length of the file in bytes.
int	getFileVersion() Returns the version of the file.
ESRIRecord	getNextRecord() Returns the next record from the shape file as an ESRIRecord.
int	getShapeType() Returns the shape type of the file.
protected void	initHeader() Reads or writes the header of a Shape file.
protected void	readHeader() Reads and parses the header of the file.
void	setShapeType(int newShapeType) Sets the shape type of the file.
void	verify(boolean repair, boolean verbose) Verifies the contents of a shape file.
protected void	verifyRecordBuffer(int size) Verifies that the record buffer is big enough to hold the given number of bytes.
protected void	writeHeader() Writes a blank header into the shape file.

Methods inherited from class de.fhg.igd.earth.model.input.shapefile.ShapeUtils

readBEInt, readBox, readLEDouble, readLEInt, readLEInt, readLELong, readPoint, writeBEInt, writeBox, writeLEDouble, writeLEInt, writeLELong, writePoint

Methods inherited from class java.lang.Object

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

Field Detail

SHAPE_FILE_CODE

public static final int SHAPE_FILE_CODE

A Shape File's magic number.

See Also:

Constant Field Values

SHAPE_FILE_VERSION

public static final int SHAPE_FILE_VERSION

The currently handled version of Shape Files.

See Also:

Constant Field Values

DEFAULT_RECORD_BUFFER_SIZE

public static final int DEFAULT_RECORD_BUFFER_SIZE

A default record size. Automatically increased on demand.

See Also:

Constant Field Values

raf

protected RandomAccessFile raf

The read/write class for shape files.

header

protected byte[] header

The buffer that holds the 100 byte header.

fileLength

protected long fileLength

Holds the length of the file, in bytes.

fileVersion

protected int fileVersion

Holds the version of the file, as an int.

fileShapeType

protected int fileShapeType

Holds the shape type of the file.

fileBounds

protected ESRIBoundingBox fileBounds

Holds the bounds of the file (four doubles).

recHdr

protected byte[] recHdr

A buffer for current record's header.

recBuf

protected byte[] recBuf

A buffer for the current record's data.

Constructor Detail

ShapeFile

public ShapeFile(String name)
          throws IOException

Construct a ShapeFile from a file name.

Throws:

IOException - if something goes wrong opening or reading the file.

ShapeFile

public ShapeFile(File file)
          throws IOException

Construct a ShapeFile from the given File.

Parameters:

file - A file object representing an ESRI Shape File

Throws:

IOException - if something goes wrong opening or reading the file.

Method Detail

initHeader

protected void initHeader()
                   throws IOException

Reads or writes the header of a Shape file. If the file is empty, a blank header is written and then read. If the file is not empty, the header is read.

After this function runs, the file pointer is set to byte 100, the first byte of the first record in the file.

Throws:

IOException - if something goes wrong reading or writing the shape file

writeHeader

protected void writeHeader()
                    throws IOException

Writes a blank header into the shape file.

Throws:

IOException - if something goes wrong writing the shape file

readHeader

protected void readHeader()
                   throws IOException

Reads and parses the header of the file. Values from the header are stored in the fields of this class.

Throws:

IOException - if something goes wrong reading the file

See Also:

header, fileVersion, fileLength, fileShapeType, fileBounds

getFileLength

public long getFileLength()

Returns the length of the file in bytes.

Returns:

the file length

getFileVersion

public int getFileVersion()

Returns the version of the file. The only currently supported version is 1000 (which represents version 1).

Returns:

the file version

getShapeType

public int getShapeType()

Returns the shape type of the file. Shape files do not mix shape types; all the shapes are of the same type.

Returns:

the file's shape type

setShapeType

public void setShapeType(int newShapeType)
                  throws IOException,
                         IllegalArgumentException

Sets the shape type of the file. If the file has a shape type already, it cannot be set. If it does not have a shape type, it is set and written to the file in the header.

Shape types are enumerated in the class ShapeUtils.

Parameters:

newShapeType - the new shape type

Throws:

IOException - if something goes wrong writing the file

IllegalArgumentException - if file already has a shape type

See Also:

ShapeUtils

getBoundingBox

public ESRIBoundingBox getBoundingBox()

Returns the bounding box of this shape file. The bounding box is the smallest rectangle that encloses all the shapes in the file.

Returns:

the bounding box

getNextRecord

public ESRIRecord getNextRecord()
                         throws IOException

Returns the next record from the shape file as an ESRIRecord. Each successive call gets the next record. There is no way to go back a record. When there are no more records, null is returned.

Returns:

a record, or null if there are no more records

Throws:

IOException - if something goes wrong reading the file

add

public void add(ESRIRecord r)
         throws IOException

Adds a record to the end of this file. The record is written to the file at the end of the last record.

Parameters:

r - the record to be added

Throws:

IOException - if something goes wrong writing to the file

close

public void close()
           throws IOException

Closes the shape file and disposes of resources.

Throws:

IOException - if something goes wrong closing the file

verify

public void verify(boolean repair,
                   boolean verbose)
            throws IOException

Verifies the contents of a shape file. The header is verified for file length, bounding box, and shape type. The records are verified for shape type and record number. The file is verified for proper termination (EOF at the end of a record).

Parameters:

repair - NOT CURRENTLY USED - would signal that the file should be repaired if possible

verbose - NOT CURRENTLY USED - would cause the verifier to display progress and status

Throws:

IOException - if something goes wrong reading or writing the file

verifyRecordBuffer

protected void verifyRecordBuffer(int size)

Verifies that the record buffer is big enough to hold the given number of bytes. If it is not big enough a new buffer is created that can hold the given number of bytes.

Parameters:

size - the number of bytes the buffer needs to hold