com.adobe.internal.io

Class RandomAccessFileByteReader

java.lang.Object

com.adobe.internal.io.RandomAccessFileByteReader

All Implemented Interfaces:

ByteReader

public class RandomAccessFileByteReader
extends Object

An implementation of the ByteReader interface that provides access to a RandomAccessFile. This implementation uses buffering to limit the number of calls to the methods of the RandomAccessFile class. This is because such methods use JNI and any calls to native code from Java are very slow. This class is not threadsafe. It is not safe to pass an instance of this class to multiple threads. It is not safe to pass an instance of this class to multiple users even if in the same thread. It is not safe to give the same RandomAccessFile to multiple instances of this class.

Field Summary

Fields inherited from interface com.adobe.internal.io.ByteReader

EOF

Constructor Summary

Constructors

Constructor and Description
RandomAccessFileByteReader(RandomAccessFile file) Constructor.

Method Summary

Modifier and Type	Method and Description
void	close() Closes this ByteReader and releases any system resources associated with this stream.
long	length() Returns the number of total bytes in the repository that are visible through this API.
int	read(long position) Read a single byte from the underlying bytes at the given position.
int	read(long position, byte[] b, int offset, int length) Transfers bytes from the underlying repository into the given destination array.

Methods inherited from class java.lang.Object

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

Constructor Detail

RandomAccessFileByteReader

public RandomAccessFileByteReader(RandomAccessFile file)

Constructor.

Parameters:

file - the file to wrap.

Method Detail

read

public int read(long position)
         throws IOException

Description copied from interface: ByteReader

Read a single byte from the underlying bytes at the given position.

Specified by:

read in interface ByteReader

Parameters:

position - the position to read the byte from.

Returns:

the byte at the postion or EOF if the position is outside of the legal range.

Throws:

IOException - if an error occurs during the read operation

See Also:

ByteReader.read(long)

read

public int read(long position,
                byte[] b,
                int offset,
                int length)
         throws IOException

Description copied from interface: ByteReader

Transfers bytes from the underlying repository into the given destination array. Copy up to length bytes from the repository starting at the postion given into the given array starting at the given offset.

Specified by:

read in interface ByteReader

Parameters:

position - the position to read the byte from.

b - the array to write the bytes into.

offset - the offset in the array at which the first byte is written.

length - the maximum number of bytes to write into the array.

Returns:

the number of bytes actually written to the array.

Throws:

IOException - if an error occurs during the read operation

See Also:

ByteReader.read(long, byte[], int, int)

length

public long length()
            throws IOException

Description copied from interface: ByteReader

Returns the number of total bytes in the repository that are visible through this API.

Specified by:

length in interface ByteReader

Returns:

the number of bytes in the repository.

Throws:

IOException - if an error occurs while trying to determine the length

See Also:

ByteReader.length()

close

public void close()
           throws IOException

Description copied from interface: ByteReader

Closes this ByteReader and releases any system resources associated with this stream.

Specified by:

close in interface ByteReader

Throws:

IOException - if an error occurs while trying to close

See Also:

ByteReader.close()