com.levigo.jadice.document.io
Class SeekableInputStream

java.lang.Object
  java.io.InputStream
      com.levigo.jadice.document.io.SeekableInputStream

All Implemented Interfaces:

Closeable, DataInput, ImageInputStream

Direct Known Subclasses:

CarbonCopyStream, ConcatenatedInputStream, FileCacheInputStream, HTTPRangeRequestStream, MemoryInputStream, RandomAccessFileInputStream, SeekableLookaheadStream, SubfileSeekableInputStream, UncloseableSeekableInputStream

public abstract class SeekableInputStream
extends InputStream
implements ImageInputStream

This class defines an extended InputStream which is seekable.

Field Summary

protected int	bitOffset The current bit offset within the stream.
protected ByteOrder	byteOrder The byte order of the stream as an instance of the enumeration class java.nio.ByteOrder, where ByteOrder.BIG_ENDIAN indicates network byte order and ByteOrder.LITTLE_ENDIAN indicates the reverse order.
protected long	flushedPos The position prior to which data may be discarded.

Constructor Summary

SeekableInputStream()

Method Summary

protected void	checkClosed() Throws an IOException if the stream has been closed.
void	close() Closes this seekable input stream.
protected void	finalize() Finalizes this object prior to garbage collection.
void	flush()
void	flushBefore(long pos)
int	getBitOffset()
ByteOrder	getByteOrder()
long	getFlushedPosition()
abstract long	getSizeEstimate() A rough estimated size for this stream instance, which is used for internal cache management.
boolean	isCached() Default implementation returns false.
boolean	isCachedFile() Default implementation returns false.
boolean	isCachedMemory() Default implementation returns false.
abstract long	length() Returns the length of this stream contents, if available.
void	mark() Pushes the current stream position onto a stack of marked positions.
void	mark(int readlimit)
abstract int	read() Reads a single byte from the stream and returns it as an int between 0 and 255.
int	read(byte[] b) A convenience method that calls read(b, 0, b.length).
abstract int	read(byte[] b, int off, int len) Reads up to len bytes from the stream, and stores them into b starting at index off.
int	readBit()
long	readBits(int numBits)
boolean	readBoolean()
byte	readByte()
void	readBytes(IIOByteBuffer buf, int len)
char	readChar()
double	readDouble()
float	readFloat()
void	readFully(byte[] b)
void	readFully(byte[] b, int off, int len)
void	readFully(char[] c, int off, int len)
void	readFully(double[] d, int off, int len)
void	readFully(float[] f, int off, int len)
void	readFully(int[] i, int off, int len)
void	readFully(long[] l, int off, int len)
void	readFully(short[] s, int off, int len)
int	readInt()
int	readInt(int appliedBytes) Reads appliedBytes bytes from the stream, and (conceptually) concatenates them according to the current byte order and returns the result as an int.
String	readLine()
long	readLong()
short	readShort()
int	readUnsignedByte()
long	readUnsignedInt()
long	readUnsignedInt(int appliedBytes) Reads appliedBytes bytes from the stream, and (conceptually) concatenates them according to the current byte order, converts the result to a long, masks it with 0xffffffffL in order to strip off any sign-extension bits, and returns the result as an unsigned long value.
int	readUnsignedShort()
String	readUTF()
void	reset() Resets the current stream byte and bit positions from the stack of marked positions.
void	resetToInitialState() Resets the current stream byte, bit positions from the stack of marked positions, the flushed position and seeks to 0.
abstract void	seek(long pos) Sets the current stream position, measured from the beginning of this data stream, at which the next read occurs.
void	setBitOffset(int bitOffset)
void	setByteOrder(ByteOrder byteOrder)
long	skip(long n)
int	skipBytes(int n) Advances the current stream position by calling seek(getStreamPosition() + n).
long	skipBytes(long n) Advances the current stream position by calling seek(getStreamPosition() + n).

Methods inherited from class java.io.InputStream

available, markSupported

Methods inherited from class java.lang.Object

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

Methods inherited from interface javax.imageio.stream.ImageInputStream

getStreamPosition

Field Detail

byteOrder

protected ByteOrder byteOrder

The byte order of the stream as an instance of the enumeration class java.nio.ByteOrder, where ByteOrder.BIG_ENDIAN indicates network byte order and ByteOrder.LITTLE_ENDIAN indicates the reverse order. By default, the value is ByteOrder.BIG_ENDIAN.

bitOffset

protected int bitOffset

The current bit offset within the stream. Subclasses are responsible for keeping this value current from any method they override that alters the bit offset.

flushedPos

protected long flushedPos

The position prior to which data may be discarded. Seeking to a smaller position is not allowed. flushedPos will always be >= 0.

Constructor Detail

SeekableInputStream

public SeekableInputStream()

Method Detail

checkClosed

protected final void checkClosed()
                          throws IOException

Throws an IOException if the stream has been closed. Subclasses may call this method from any of their methods that require the stream not to be closed.

Throws:

IOException - if the stream is closed.

close

public void close()
           throws IOException

Closes this seekable input stream. Further attempts to read from it will throw IOExceptions. Additional attempts to close(), however, have no effect.

Specified by:

close in interface Closeable

Specified by:

close in interface ImageInputStream

Overrides:

close in class InputStream

Throws:

IOException

See Also:

InputStream.close()

finalize

protected void finalize()
                 throws Throwable

Finalizes this object prior to garbage collection. The close method is called to close any open input source. This method should not be called from application code.

Overrides:

finalize in class Object

Throws:

Throwable - if an error occurs during superclass finalization.

flush

public void flush()
           throws IOException

Specified by:

flush in interface ImageInputStream

Throws:

IOException

See Also:

ImageInputStream.flush()

flushBefore

public void flushBefore(long pos)
                 throws IOException

Specified by:

flushBefore in interface ImageInputStream

Throws:

IOException

See Also:

ImageInputStream.flushBefore(long)

getBitOffset

public int getBitOffset()
                 throws IOException

Specified by:

getBitOffset in interface ImageInputStream

Throws:

IOException

See Also:

ImageInputStream.getBitOffset()

getByteOrder

public ByteOrder getByteOrder()

Specified by:

getByteOrder in interface ImageInputStream

See Also:

ImageInputStream.getByteOrder()

getFlushedPosition

public long getFlushedPosition()

Specified by:

getFlushedPosition in interface ImageInputStream

See Also:

ImageInputStream.getFlushedPosition()

getSizeEstimate

public abstract long getSizeEstimate()

A rough estimated size for this stream instance, which is used for internal cache management.

Returns:

an estimated size

isCached

public boolean isCached()

Default implementation returns false. Subclasses should override this if they cache data.

Specified by:

isCached in interface ImageInputStream

See Also:

ImageInputStream.isCached()

isCachedFile

public boolean isCachedFile()

Default implementation returns false. Subclasses should override this if they cache data in a temporary file.

Specified by:

isCachedFile in interface ImageInputStream

See Also:

ImageInputStream.isCachedFile()

isCachedMemory

public boolean isCachedMemory()

Default implementation returns false. Subclasses should override this if they cache data in main memory.

Specified by:

isCachedMemory in interface ImageInputStream

See Also:

ImageInputStream.isCachedMemory()

length

public abstract long length()
                     throws IOException

Returns the length of this stream contents, if available. Otherwise -1L will be returned.

Specified by:

length in interface ImageInputStream

Returns:

the length, measured in bytes or -1L if unknown.

Throws:

IOException - if an I/O error occurs.

mark

public void mark()

Pushes the current stream position onto a stack of marked positions.

Specified by:

mark in interface ImageInputStream

mark

public void mark(int readlimit)

Overrides:

mark in class InputStream

read

public abstract int read()
                  throws IOException

Reads a single byte from the stream and returns it as an int between 0 and 255. If EOF is reached, -1 is returned.

Subclasses must provide an implementation for this method. The subclass implementation should update the stream position before exiting.

The bit offset within the stream must be reset to zero before the read occurs.

Specified by:

read in interface ImageInputStream

Specified by:

read in class InputStream

Returns:

the value of the next byte in the stream, or -1 if EOF is reached.

Throws:

IOException - if the stream has been closed.

read

public int read(byte[] b)
         throws IOException

A convenience method that calls read(b, 0, b.length).

The bit offset within the stream is reset to zero before the read occurs.

Specified by:

read in interface ImageInputStream

Overrides:

read in class InputStream

Parameters:

b - the byte buffer to fill up

Returns:

the number of bytes actually read, or -1 to indicate EOF.

Throws:

NullPointerException - if b is null.

IOException - if an I/O error occurs.

read

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

Reads up to len bytes from the stream, and stores them into b starting at index off. If no bytes can be read because the end of the stream has been reached, -1 is returned.

The bit offset within the stream must be reset to zero before the read occurs.

Subclasses must provide an implementation for this method. The subclass implementation should update the stream position before exiting.

Specified by:

read in interface ImageInputStream

Overrides:

read in class InputStream

Parameters:

b - an array of bytes to be written to.

off - the starting position within b to write to.

len - the maximum number of bytes to read.

Returns:

the number of bytes actually read, or -1 to indicate EOF.

Throws:

IndexOutOfBoundsException - if off is negative, len is negative, or off + len is greater than b.length.

NullPointerException - if b is null.

IOException - if an I/O error occurs.

readBit

public int readBit()
            throws IOException

Specified by:

readBit in interface ImageInputStream

Throws:

IOException

See Also:

ImageInputStream.readBit()

readBits

public long readBits(int numBits)
              throws IOException

Specified by:

readBits in interface ImageInputStream

Throws:

IOException

See Also:

ImageInputStream.readBits(int)

readBoolean

public boolean readBoolean()
                    throws IOException

Specified by:

readBoolean in interface DataInput

Specified by:

readBoolean in interface ImageInputStream

Throws:

IOException

See Also:

ImageInputStream.readBoolean()

readByte

public byte readByte()
              throws IOException

Specified by:

readByte in interface DataInput

Specified by:

readByte in interface ImageInputStream

Throws:

IOException

See Also:

ImageInputStream.readByte()

readBytes

public void readBytes(IIOByteBuffer buf,
                      int len)
               throws IOException

Specified by:

readBytes in interface ImageInputStream

Throws:

IOException

See Also:

ImageInputStream.readBytes(javax.imageio.stream.IIOByteBuffer, int)

readChar

public char readChar()
              throws IOException

Specified by:

readChar in interface DataInput

Specified by:

readChar in interface ImageInputStream

Throws:

IOException

See Also:

ImageInputStream.readChar()

readDouble

public double readDouble()
                  throws IOException

Specified by:

readDouble in interface DataInput

Specified by:

readDouble in interface ImageInputStream

Throws:

IOException

See Also:

ImageInputStream.readDouble()

readFloat

public float readFloat()
                throws IOException

Specified by:

readFloat in interface DataInput

Specified by:

readFloat in interface ImageInputStream

Throws:

IOException

See Also:

ImageInputStream.readFloat()

readFully

public void readFully(byte[] b)
               throws IOException

Specified by:

readFully in interface DataInput

Specified by:

readFully in interface ImageInputStream

Throws:

IOException

See Also:

ImageInputStream.readFully(byte[])

readFully

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

Specified by:

readFully in interface DataInput

Specified by:

readFully in interface ImageInputStream

Throws:

IOException

See Also:

ImageInputStream.readFully(byte[], int, int)

readFully

public void readFully(char[] c,
                      int off,
                      int len)
               throws IOException

Specified by:

readFully in interface ImageInputStream

Throws:

IOException

See Also:

ImageInputStream.readFully(char[], int, int)

readFully

public void readFully(double[] d,
                      int off,
                      int len)
               throws IOException

Specified by:

readFully in interface ImageInputStream

Throws:

IOException

See Also:

ImageInputStream.readFully(double[], int, int)

readFully

public void readFully(float[] f,
                      int off,
                      int len)
               throws IOException

Specified by:

readFully in interface ImageInputStream

Throws:

IOException

See Also:

ImageInputStream.readFully(float[], int, int)

readFully

public void readFully(int[] i,
                      int off,
                      int len)
               throws IOException

Specified by:

readFully in interface ImageInputStream

Throws:

IOException

See Also:

ImageInputStream.readFully(int[], int, int)

readFully

public void readFully(long[] l,
                      int off,
                      int len)
               throws IOException

Specified by:

readFully in interface ImageInputStream

Throws:

IOException

See Also:

ImageInputStream.readFully(long[], int, int)

readFully

public void readFully(short[] s,
                      int off,
                      int len)
               throws IOException

Specified by:

readFully in interface ImageInputStream

Throws:

IOException

See Also:

ImageInputStream.readFully(short[], int, int)

readInt

public int readInt()
            throws IOException

Specified by:

readInt in interface DataInput

Specified by:

readInt in interface ImageInputStream

Throws:

IOException

See Also:

ImageInputStream.readInt()

readInt

public int readInt(int appliedBytes)
            throws IOException

Reads appliedBytes bytes from the stream, and (conceptually) concatenates them according to the current byte order and returns the result as an int. As consequence, appliedBytes have to be greater than 0 and smaller or equals than 4. All other values of appliedBytes will cause an IllegalArgumentException.

The bit offset within the stream is ignored and treated as though it were zero.

Parameters:

appliedBytes -

Returns:

a signed int value from the stream.

Throws:

EOFException - if the stream reaches the end before reading all the bytes.

IOException - if an I/O error occurs.

See Also:

getByteOrder()

readLine

public String readLine()
                throws IOException

Specified by:

readLine in interface DataInput

Specified by:

readLine in interface ImageInputStream

Throws:

IOException

See Also:

ImageInputStream.readLine()

readLong

public long readLong()
              throws IOException

Specified by:

readLong in interface DataInput

Specified by:

readLong in interface ImageInputStream

Throws:

IOException

See Also:

ImageInputStream.readLong()

readShort

public short readShort()
                throws IOException

Specified by:

readShort in interface DataInput

Specified by:

readShort in interface ImageInputStream

Throws:

IOException

See Also:

ImageInputStream.readShort()

readUnsignedByte

public int readUnsignedByte()
                     throws IOException

Specified by:

readUnsignedByte in interface DataInput

Specified by:

readUnsignedByte in interface ImageInputStream

Throws:

IOException

See Also:

ImageInputStream.readUnsignedByte()

readUnsignedInt

public long readUnsignedInt()
                     throws IOException

Specified by:

readUnsignedInt in interface ImageInputStream

Throws:

IOException

See Also:

ImageInputStream.readUnsignedInt()

readUnsignedInt

public long readUnsignedInt(int appliedBytes)
                     throws IOException

Reads appliedBytes bytes from the stream, and (conceptually) concatenates them according to the current byte order, converts the result to a long, masks it with 0xffffffffL in order to strip off any sign-extension bits, and returns the result as an unsigned long value. As consequence, appliedBytes have to be greater than 0 and smaller or equals than 4. All other values of appliedBytes will cause an IllegalArgumentException.

The bit offset within the stream is reset to zero before the read occurs.

Parameters:

appliedBytes -

Returns:

an unsigned int value from the stream, as a long.

Throws:

EOFException - if the stream reaches the end before reading all the bytes.

IOException - if an I/O error occurs.

See Also:

getByteOrder()

readUnsignedShort

public int readUnsignedShort()
                      throws IOException

Specified by:

readUnsignedShort in interface DataInput

Specified by:

readUnsignedShort in interface ImageInputStream

Throws:

IOException

See Also:

ImageInputStream.readUnsignedShort()

readUTF

public String readUTF()
               throws IOException

Specified by:

readUTF in interface DataInput

Specified by:

readUTF in interface ImageInputStream

Throws:

IOException

See Also:

ImageInputStream.readUTF()

reset

public void reset()
           throws IOException

Resets the current stream byte and bit positions from the stack of marked positions.

An IOException will be thrown if the previous marked position lies in the discarded portion of the stream.

Specified by:

reset in interface ImageInputStream

Overrides:

reset in class InputStream

Throws:

IOException - if an I/O error occurs.

resetToInitialState

public void resetToInitialState()
                         throws IOException

Resets the current stream byte, bit positions from the stack of marked positions, the flushed position and seeks to 0.

Throws:

IOException - if an I/O error occurs.

seek

public abstract void seek(long pos)
                   throws IOException

Sets the current stream position, measured from the beginning of this data stream, at which the next read occurs. The offset may be set beyond the end of this data stream. Setting the offset beyond the end does not change the data length, an EOFException will be thrown only if a read is performed. The bit offset is set to 0.

An IndexOutOfBoundsException will be thrown if pos is smaller than the flushed position (as returned by getflushedPosition).

It is legal to seek past the end of the file; an EOFException will be thrown only if a read is performed.

Specified by:

seek in interface ImageInputStream

Parameters:

pos - a long containing the desired file pointer position.

Throws:

IndexOutOfBoundsException - if pos is smaller than the flushed position.

IOException - if any other I/O error occurs.

setBitOffset

public void setBitOffset(int bitOffset)
                  throws IOException

Specified by:

setBitOffset in interface ImageInputStream

Throws:

IOException

See Also:

ImageInputStream.setBitOffset(int)

setByteOrder

public void setByteOrder(ByteOrder byteOrder)

Specified by:

setByteOrder in interface ImageInputStream

See Also:

ImageInputStream.setByteOrder(java.nio.ByteOrder)

skip

public long skip(long n)
          throws IOException

Overrides:

skip in class InputStream

Throws:

IOException

skipBytes

public int skipBytes(int n)
              throws IOException

Advances the current stream position by calling seek(getStreamPosition() + n).

The bit offset is reset to zero.

Specified by:

skipBytes in interface DataInput

Specified by:

skipBytes in interface ImageInputStream

Parameters:

n - the number of bytes to seek forward.

Returns:

an int representing the number of bytes skipped.

Throws:

IOException - if getStreamPosition throws an IOException when computing either the starting or ending position.

skipBytes

public long skipBytes(long n)
               throws IOException

Advances the current stream position by calling seek(getStreamPosition() + n).

The bit offset is reset to zero.

Specified by:

skipBytes in interface ImageInputStream

Parameters:

n - the number of bytes to seek forward.

Returns:

a long representing the number of bytes skipped.

Throws:

IOException - if getStreamPosition throws an IOException when computing either the starting or ending position.