org.verapdf.io

Class SeekableInputStream

java.lang.Object

java.io.InputStream

org.verapdf.as.io.ASInputStream

org.verapdf.io.SeekableInputStream

All Implemented Interfaces:

Closeable, AutoCloseable

Direct Known Subclasses:

ASMemoryInStream, InternalInputStream

public abstract class SeekableInputStream
extends ASInputStream

Represents stream in which seek for a particular byte offset can be performed. On creation, contents of this stream should be written into file or memory buffer.

Author:

Sergey Shemyakov

Field Summary

Fields inherited from class org.verapdf.as.io.ASInputStream

isClosed, isSourceClosed, resourceUsers

Constructor Summary

Constructors

Constructor and Description
SeekableInputStream()

Method Summary

Modifier and Type	Method and Description
void	decrementResourceUsers() Method decrements number of resource users.
abstract long	getOffset() Gets offset of current byte.
static SeekableInputStream	getSeekableStream(InputStream stream) Returns InternalInputStream or ASMemoryInStream constructed from given stream depending on stream length.
abstract ASInputStream	getStream(long startOffset, long length) Gets substream of this stream that starts at given offset and has given length.
abstract long	getStreamLength() Gets total length of stream.
void	incrementResourceUsers() Method increments number of resource users.
boolean	isEOF()
abstract int	peek() Gets next byte without reading it.
byte	readByte() Reads next byte from stream.
abstract void	seek(long offset) Goes to a particular byte in stream.
void	seekFromCurrentPosition(long pos) Sets reading pointer several bytes forward.
void	seekFromEnd(long pos) Seeks given number of bytes from the end of stream.
void	unread() Resets reading pointer one byte backwards.
void	unread(int count) Resets reading pointer several bytes backwards.

Methods inherited from class org.verapdf.as.io.ASInputStream

close, closeResource, createStreamFromStream, read, read, reset, skip

Methods inherited from class java.io.InputStream

available, mark, markSupported, read, read, skip

Methods inherited from class java.lang.Object

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

Constructor Detail

SeekableInputStream

public SeekableInputStream()

Method Detail

seek

public abstract void seek(long offset)
                   throws IOException

Goes to a particular byte in stream.

Parameters:

offset - is offset of a byte to go to.

Throws:

IOException

getOffset

public abstract long getOffset()
                        throws IOException

Gets offset of current byte.

Returns:

offset of byte to be read next.

Throws:

IOException

getStreamLength

public abstract long getStreamLength()
                              throws IOException

Gets total length of stream.

Returns:

length of stream in bytes.

Throws:

IOException

peek

public abstract int peek()
                  throws IOException

Gets next byte without reading it.

Returns:

next byte.

Throws:

IOException

getStream

public abstract ASInputStream getStream(long startOffset,
                                        long length)
                                 throws IOException

Gets substream of this stream that starts at given offset and has given length.

Parameters:

startOffset - is starting offset of substream.

length - is length of substream.

Throws:

IOException

incrementResourceUsers

public void incrementResourceUsers()

Method increments number of resource users. closeResource

Specified by:

incrementResourceUsers in class ASInputStream

decrementResourceUsers

public void decrementResourceUsers()

Description copied from class: ASInputStream

Method decrements number of resource users. closeResource

Specified by:

decrementResourceUsers in class ASInputStream

isEOF

public boolean isEOF()
              throws IOException

Returns:

true if end of stream is reached.

Throws:

IOException

unread

public void unread()
            throws IOException

Resets reading pointer one byte backwards.

Throws:

IOException

unread

public void unread(int count)
            throws IOException

Resets reading pointer several bytes backwards.

Parameters:

count - is number of bytes to unread.

Throws:

IOException

seekFromCurrentPosition

public void seekFromCurrentPosition(long pos)
                             throws IOException

Sets reading pointer several bytes forward.

Parameters:

pos - is amount of bytes to skip.

Throws:

IOException

seekFromEnd

public void seekFromEnd(long pos)
                 throws IOException

Seeks given number of bytes from the end of stream.

Parameters:

pos - is a number of bytes to seek from the end of stream.

Throws:

IOException

readByte

public byte readByte()
              throws IOException

Reads next byte from stream.

Returns:

the byte read.

Throws:

IOException

getSeekableStream

public static SeekableInputStream getSeekableStream(InputStream stream)
                                             throws IOException

Returns InternalInputStream or ASMemoryInStream constructed from given stream depending on stream length.

Parameters:

stream - is stream to turn into seekable stream.

Returns:

SeekableStream that contains data of passed stream.

Throws:

IOException