com.bbn.openmap.io
Class FileInputReader

java.lang.Object
  com.bbn.openmap.io.FileInputReader

All Implemented Interfaces:

InputReader

public class FileInputReader
extends java.lang.Object
implements InputReader

This class wraps a java.io.RandomAccessFile to allow us to choose the byte-order of the underlying file. It has a user-settable byte-ordering, which is then used to properly implement the various multibyte reading members. Used for reading local files.

See Also:

RandomAccessFile, InputReader, BinaryFile

Field Summary

protected java.lang.String	absolutePath Needed for reopening files that have been closed.
protected java.io.RandomAccessFile	inputFile The underlying file input
protected java.lang.String	name Needed for input reader interface.

Constructor Summary

FileInputReader(java.io.File f)
Constructs a new BinaryFile with the specified file as the input.

FileInputReader(java.lang.String f)
Constructs a new BinaryFile with the specified file as the input.

Method Summary

long	available() Return how many bytes left to be read in the file.
java.io.RandomAccessFile	checkInputFile()
void	close() Closes the underlying file
java.lang.String	getAbsolutePath()
long	getFilePointer() Get the index of the next character to be read
java.io.RandomAccessFile	getInputFile() Get the RandomAccessFile, for querying purposes only.
java.lang.String	getName() Get the file name.
protected java.io.RandomAccessFile	init(java.io.File f) Initialize the underlying RandomAccessFile.
long	length() Local files only.
int	read() Read from the file.
int	read(byte[] b) Read from the file.
int	read(byte[] b, int off, int len) Read from the file
byte[]	readBytes(int howmany, boolean allowless) Read from the file.
void	seek(long pos) Set the index of the next character to be read.
long	skipBytes(long n) Skip over n bytes in the input file

Methods inherited from class java.lang.Object

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

Field Detail

inputFile

protected java.io.RandomAccessFile inputFile

The underlying file input

name

protected java.lang.String name

Needed for input reader interface.

absolutePath

protected java.lang.String absolutePath

Needed for reopening files that have been closed.

Constructor Detail

FileInputReader

public FileInputReader(java.io.File f)
                throws java.io.IOException

Constructs a new BinaryFile with the specified file as the input. The default byte-order is LSB first. Reads start at the first byte of the file.

Parameters:

f - the file to be opened for reading

Throws:

java.io.IOException - pass-through errors from opening a RandomAccessFile with f

See Also:

RandomAccessFile

FileInputReader

public FileInputReader(java.lang.String f)
                throws java.io.IOException

Constructs a new BinaryFile with the specified file as the input. The default byte-order is LSB first. Reads start at the first byte of the file.

Parameters:

f - the path to the file to be opened for reading.

Throws:

java.io.IOException - pass-through errors from opening a RandomAccessFile with f

See Also:

RandomAccessFile

Method Detail

getName

public java.lang.String getName()

Get the file name.

Specified by:

getName in interface InputReader

getAbsolutePath

public java.lang.String getAbsolutePath()

Returns:

the absolute path of the file.

init

protected java.io.RandomAccessFile init(java.io.File f)
                                 throws java.io.IOException

Initialize the underlying RandomAccessFile. If it's found, but there are too many files open, it calls BinaryFile.closeClosable to try to get an open file pointer from the system, and then tries again.

Parameters:

f - a java.io.File

Throws:

java.io.IOException

getInputFile

public java.io.RandomAccessFile getInputFile()

Get the RandomAccessFile, for querying purposes only. Don't use it to get data!

checkInputFile

public java.io.RandomAccessFile checkInputFile()
                                        throws java.io.IOException

Throws:

java.io.IOException

skipBytes

public long skipBytes(long n)
               throws java.io.IOException

Skip over n bytes in the input file

Specified by:

skipBytes in interface InputReader

Parameters:

n - the number of bytes to skip

Returns:

the actual number of bytes skipped. annoying, isn't it?

Throws:

java.io.IOException - Any IO errors that occur in skipping bytes in the underlying file

getFilePointer

public long getFilePointer()
                    throws java.io.IOException

Get the index of the next character to be read

Specified by:

getFilePointer in interface InputReader

Returns:

the index

Throws:

java.io.IOException - Any IO errors that occur in accessing the underlying file

seek

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

Set the index of the next character to be read.

Specified by:

seek in interface InputReader

Parameters:

pos - the position to seek to.

Throws:

java.io.IOException - Any IO Errors that occur in seeking the underlying file.

length

public long length()
            throws java.io.IOException

Local files only. Retrieve the length of the file being accessed.

Specified by:

length in interface InputReader

Returns:

the length of the file (counted in bytes)

Throws:

java.io.IOException - Any IO errors that occur in accessing the underlying file.

available

public long available()
               throws java.io.IOException

Return how many bytes left to be read in the file.

Specified by:

available in interface InputReader

Returns:

the number of bytes remaining to be read (counted in bytes)

Throws:

java.io.IOException - Any IO errors encountered in accessing the file

close

public void close()
           throws java.io.IOException

Closes the underlying file

Specified by:

close in interface InputReader

Throws:

java.io.IOException - Any IO errors encountered in accessing the file

read

public int read()
         throws java.io.IOException

Read from the file.

Specified by:

read in interface InputReader

Returns:

one byte from the file. -1 for EOF

Throws:

java.io.IOException - Any IO errors encountered in reading from the file

read

public int read(byte[] b,
                int off,
                int len)
         throws java.io.IOException

Read from the file

Specified by:

read in interface InputReader

Parameters:

b - The byte array to read into

off - the first array position to read into

len - the number of bytes to read

Returns:

the number of bytes read

Throws:

java.io.IOException - Any IO errors encountered in reading from the file

read

public int read(byte[] b)
         throws java.io.IOException

Read from the file.

Specified by:

read in interface InputReader

Parameters:

b - the byte array to read into. Equivalent to read(b, 0, b.length)

Returns:

the number of bytes read

Throws:

java.io.IOException - Any IO errors encountered in reading from the file

See Also:

RandomAccessFile.read(byte[])

readBytes

public byte[] readBytes(int howmany,
                        boolean allowless)
                 throws java.io.EOFException,
                        FormatException

Read from the file.

Specified by:

readBytes in interface InputReader

Parameters:

howmany - the number of bytes to read

allowless - if we can return fewer bytes than requested

Returns:

the array of bytes read.

Throws:

FormatException - Any IO Exceptions, plus an end-of-file encountered after reading some, but now enough, bytes when allowless was false

java.io.EOFException - Encountered an end-of-file while allowless was false, but NO bytes had been read.