com.caucho.vfs
Class RandomAccessStream

java.lang.Object
  com.caucho.vfs.RandomAccessStream

All Implemented Interfaces:

LockableStream

Direct Known Subclasses:

DatastoreRandomAccessStream, FileRandomAccessStream, JniMemoryMappedFile, JniRandomAccessFile, SpyRandomAccessStream

public abstract class RandomAccessStream
extends java.lang.Object
implements LockableStream

Reads from a file in a random-access fashion.

Constructor Summary

RandomAccessStream()

Method Summary

boolean	allocate()
void	close() Closes the stream.
void	closeImpl() Closes the stream.
void	free()
abstract long	getFilePointer() Returns the current position of the file pointer.
abstract java.io.InputStream	getInputStream() Returns an InputStream for this stream.
abstract long	getLength() Returns the length.
abstract java.io.OutputStream	getOutputStream() Returns an OutputStream for this stream.
long	getUseCount()
boolean	isOpen()
boolean	lock(boolean shared, boolean block) Lock the shared advisory lock.
abstract int	read() Read a byte from the file, advancing the pointer.
abstract int	read(byte[] buffer, int offset, int length) Reads a block starting from the current file pointer.
abstract int	read(char[] buffer, int offset, int length) Reads a block starting from the current file pointer.
abstract int	read(long fileOffset, byte[] buffer, int offset, int length) Reads a block from a given location.
abstract boolean	seek(long position) Seeks to the given position in the file.
boolean	unlock() Unlock the advisory lock.
abstract void	write(byte[] buffer, int offset, int length) Writes a block starting from the current file pointer.
abstract void	write(int b) Write a byte to the file, advancing the pointer.
abstract void	write(long fileOffset, byte[] buffer, int offset, int length) Writes a block to a given location.

Methods inherited from class java.lang.Object

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

Constructor Detail

RandomAccessStream

public RandomAccessStream()

Method Detail

getLength

public abstract long getLength()
                        throws java.io.IOException

Returns the length.

Throws:

java.io.IOException

read

public abstract int read(byte[] buffer,
                         int offset,
                         int length)
                  throws java.io.IOException

Reads a block starting from the current file pointer.

Throws:

java.io.IOException

read

public abstract int read(char[] buffer,
                         int offset,
                         int length)
                  throws java.io.IOException

Reads a block starting from the current file pointer.

Throws:

java.io.IOException

read

public abstract int read(long fileOffset,
                         byte[] buffer,
                         int offset,
                         int length)
                  throws java.io.IOException

Reads a block from a given location.

Throws:

java.io.IOException

write

public abstract void write(byte[] buffer,
                           int offset,
                           int length)
                    throws java.io.IOException

Writes a block starting from the current file pointer.

Throws:

java.io.IOException

write

public abstract void write(long fileOffset,
                           byte[] buffer,
                           int offset,
                           int length)
                    throws java.io.IOException

Writes a block to a given location.

Throws:

java.io.IOException

seek

public abstract boolean seek(long position)

Seeks to the given position in the file.

getOutputStream

public abstract java.io.OutputStream getOutputStream()
                                              throws java.io.IOException

Returns an OutputStream for this stream.

Throws:

java.io.IOException

getInputStream

public abstract java.io.InputStream getInputStream()
                                            throws java.io.IOException

Returns an InputStream for this stream.

Throws:

java.io.IOException

read

public abstract int read()
                  throws java.io.IOException

Read a byte from the file, advancing the pointer.

Throws:

java.io.IOException

write

public abstract void write(int b)
                    throws java.io.IOException

Write a byte to the file, advancing the pointer.

Throws:

java.io.IOException

getFilePointer

public abstract long getFilePointer()
                             throws java.io.IOException

Returns the current position of the file pointer.

Throws:

java.io.IOException

isOpen

public final boolean isOpen()

getUseCount

public final long getUseCount()

allocate

public final boolean allocate()

free

public final void free()

close

public final void close()

Closes the stream.

closeImpl

public void closeImpl()
               throws java.io.IOException

Closes the stream.

Throws:

java.io.IOException

lock

public boolean lock(boolean shared,
                    boolean block)

Description copied from interface: LockableStream

Lock the shared advisory lock. This method will create a shared "read" lock when the shared argument is true and an exclusive "write" lock when the shared argument is false. If the block argument is false then this call will not block if the lock can't be obtained.

Specified by:

lock in interface LockableStream

unlock

public boolean unlock()

Description copied from interface: LockableStream

Unlock the advisory lock. Return true if a lock was held, false otherwise.

Specified by:

unlock in interface LockableStream