org.apache.pdfbox.io

Class RandomAccessBufferedFileInputStream

java.lang.Object

java.io.InputStream

org.apache.pdfbox.io.RandomAccessBufferedFileInputStream

All Implemented Interfaces:

Closeable, AutoCloseable, RandomAccessRead

public class RandomAccessBufferedFileInputStream
extends InputStream
implements RandomAccessRead

Provides InputStream access to portions of a file combined with buffered reading of content. Start of next bytes to read can be set via seek method. File is accessed via RandomAccessFile and is read in byte chunks which are cached.

Author:

Timo Boehme

Constructor Summary

Constructors

Constructor and Description
RandomAccessBufferedFileInputStream(File file) Create a random access input stream instance for the given file.
RandomAccessBufferedFileInputStream(InputStream input) Create a random access input stream for the given input stream by copying the data to a temporary file.
RandomAccessBufferedFileInputStream(String filename) Create a random access input stream instance for the file with the given name.

Method Summary

Modifier and Type	Method and Description
int	available() Returns an estimate of the number of bytes that can be read.
void	close()
long	getPosition() Returns offset in file at which next byte would be read.
boolean	isClosed() Returns true if this stream has been closed.
boolean	isEOF() A simple test to see if we are at the end of the data.
long	length() The total number of bytes that are available.
int	peek() This will peek at the next byte.
int	read() Read a single byte of data.
int	read(byte[] b) Read a buffer of data.
int	read(byte[] b, int off, int len) Read a buffer of data.
byte[]	readFully(int length) Reads a given number of bytes.
void	rewind(int bytes) Seek backwards the given number of bytes.
void	seek(long newOffset) Seeks to new position.
long	skip(long n)

Methods inherited from class java.io.InputStream

mark, markSupported, reset

Methods inherited from class java.lang.Object

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

Constructor Detail

RandomAccessBufferedFileInputStream

public RandomAccessBufferedFileInputStream(String filename)
                                    throws IOException

Create a random access input stream instance for the file with the given name.

Parameters:

filename - the filename of the file to be read.

Throws:

IOException - if something went wrong while accessing the given file.

RandomAccessBufferedFileInputStream

public RandomAccessBufferedFileInputStream(File file)
                                    throws IOException

Create a random access input stream instance for the given file.

Parameters:

file - the file to be read.

Throws:

IOException - if something went wrong while accessing the given file.

RandomAccessBufferedFileInputStream

public RandomAccessBufferedFileInputStream(InputStream input)
                                    throws IOException

Create a random access input stream for the given input stream by copying the data to a temporary file.

Parameters:

input - the input stream to be read. It will be closed by this method.

Throws:

IOException - if something went wrong while creating the temporary file.

Method Detail

getPosition

public long getPosition()

Returns offset in file at which next byte would be read.

Specified by:

getPosition in interface RandomAccessRead

Returns:

offset of next byte which will be returned with next RandomAccessRead.read() (if no more bytes are left it returns a value >= length of source)

seek

public void seek(long newOffset)
          throws IOException

Seeks to new position. If new position is outside of current page the new page is either taken from cache or read from file and added to cache.

Specified by:

seek in interface RandomAccessRead

Parameters:

newOffset - the position to seek to.

Throws:

IOException - if something went wrong.

read

public int read()
         throws IOException

Description copied from interface: RandomAccessRead

Read a single byte of data.

Specified by:

read in interface RandomAccessRead

Specified by:

read in class InputStream

Returns:

The byte of data that is being read.

Throws:

IOException - If there is an error while reading the data.

read

public int read(byte[] b)
         throws IOException

Description copied from interface: RandomAccessRead

Read a buffer of data.

Specified by:

read in interface RandomAccessRead

Overrides:

read in class InputStream

Parameters:

b - The buffer to write the data to.

Returns:

The number of bytes that were actually read.

Throws:

IOException - If there was an error while reading the data.

read

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

Description copied from interface: RandomAccessRead

Read a buffer of data.

Specified by:

read in interface RandomAccessRead

Overrides:

read in class InputStream

Parameters:

b - The buffer to write the data to.

off - Offset into the buffer to start writing.

len - The amount of data to attempt to read.

Returns:

The number of bytes that were actually read.

Throws:

IOException - If there was an error while reading the data.

available

public int available()
              throws IOException

Description copied from interface: RandomAccessRead

Returns an estimate of the number of bytes that can be read.

Specified by:

available in interface RandomAccessRead

Overrides:

available in class InputStream

Returns:

the number of bytes that can be read

Throws:

IOException - if this random access has been closed

skip

public long skip(long n)
          throws IOException

Overrides:

skip in class InputStream

Throws:

IOException

length

public long length()
            throws IOException

Description copied from interface: RandomAccessRead

The total number of bytes that are available.

Specified by:

length in interface RandomAccessRead

Returns:

The number of bytes available.

Throws:

IOException - If there is an IO error while determining the length of the data stream.

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Overrides:

close in class InputStream

Throws:

IOException

isClosed

public boolean isClosed()

Description copied from interface: RandomAccessRead

Returns true if this stream has been closed.

Specified by:

isClosed in interface RandomAccessRead

peek

public int peek()
         throws IOException

Description copied from interface: RandomAccessRead

This will peek at the next byte.

Specified by:

peek in interface RandomAccessRead

Returns:

The next byte on the stream, leaving it as available to read.

Throws:

IOException - If there is an error reading the next byte.

rewind

public void rewind(int bytes)
            throws IOException

Description copied from interface: RandomAccessRead

Seek backwards the given number of bytes.

Specified by:

rewind in interface RandomAccessRead

Parameters:

bytes - the number of bytes to be seeked backwards

Throws:

IOException - If there is an error while seeking

readFully

public byte[] readFully(int length)
                 throws IOException

Description copied from interface: RandomAccessRead

Reads a given number of bytes.

Specified by:

readFully in interface RandomAccessRead

Parameters:

length - the number of bytes to be read

Returns:

a byte array containing the bytes just read

Throws:

IOException - if an I/O error occurs while reading data

isEOF

public boolean isEOF()
              throws IOException

Description copied from interface: RandomAccessRead

A simple test to see if we are at the end of the data.

Specified by:

isEOF in interface RandomAccessRead

Returns:

true if we are at the end of the data.

Throws:

IOException - If there is an error reading the next byte.