com.levigo.jadice.document.io
Class SeekableLookaheadStream

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

All Implemented Interfaces:

Closeable, DataInput, ImageInputStream

public class SeekableLookaheadStream
extends SeekableInputStream

Nested Class Summary

static class

SeekableLookaheadStream.MaxLookaheadReachedException

Field Summary

protected static int

DEFAULT_LOOKAHEAD_BUFFER_SIZE

Fields inherited from class com.levigo.jadice.document.io.SeekableInputStream

bitOffset, byteOrder, flushedPos

Constructor Summary

SeekableLookaheadStream(SeekableInputStream source)

SeekableLookaheadStream(SeekableInputStream source, int maxLookahead)

Method Summary

void	consume(int count) consume the specified number of characters looked ahead.
protected boolean	fill()
protected int	getBufSize()
protected int	getInBufPos()
long	getSizeEstimate() A rough estimated size for this stream instance, which is used for internal cache management.
protected SeekableInputStream	getSource()
long	getStreamPosition()
long	length() Returns the length of this stream contents, if available.
int	lookahead(int index)
int	read() Reads a single byte from the stream and returns it as an int between 0 and 255.
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.
protected void	resetBuffer()
void	seek(long offset) Sets the current stream position, measured from the beginning of this data stream, at which the next read occurs.

Methods inherited from class com.levigo.jadice.document.io.SeekableInputStream

checkClosed, close, finalize, flush, flushBefore, getBitOffset, getByteOrder, getFlushedPosition, isCached, isCachedFile, isCachedMemory, mark, mark, read, readBit, readBits, readBoolean, readByte, readBytes, readChar, readDouble, readFloat, readFully, readFully, readFully, readFully, readFully, readFully, readFully, readFully, readInt, readInt, readLine, readLong, readShort, readUnsignedByte, readUnsignedInt, readUnsignedInt, readUnsignedShort, readUTF, reset, resetToInitialState, setBitOffset, setByteOrder, skip, skipBytes, skipBytes

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

Field Detail

DEFAULT_LOOKAHEAD_BUFFER_SIZE

protected static final int DEFAULT_LOOKAHEAD_BUFFER_SIZE

See Also:

Constant Field Values

Constructor Detail

SeekableLookaheadStream

public SeekableLookaheadStream(SeekableInputStream source,
                               int maxLookahead)

SeekableLookaheadStream

public SeekableLookaheadStream(SeekableInputStream source)

Method Detail

read

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

Description copied from class: SeekableInputStream

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

Specified by:

read in class SeekableInputStream

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:

IOException - if an I/O error occurs.

read

public int read()
         throws IOException

Description copied from class: SeekableInputStream

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 SeekableInputStream

Returns:

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

Throws:

IOException - if the stream has been closed.

length

public long length()
            throws IOException

Description copied from class: SeekableInputStream

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

Specified by:

length in interface ImageInputStream

Specified by:

length in class SeekableInputStream

Returns:

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

Throws:

IOException - if an I/O error occurs.

lookahead

public int lookahead(int index)
              throws IOException

Throws:

IOException

seek

public void seek(long offset)
          throws IOException

Description copied from class: SeekableInputStream

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

Specified by:

seek in class SeekableInputStream

Parameters:

offset - a long containing the desired file pointer position.

Throws:

IOException - if any other I/O error occurs.

resetBuffer

protected void resetBuffer()

getSource

protected SeekableInputStream getSource()

consume

public void consume(int count)
             throws IOException

consume the specified number of characters looked ahead.

Parameters:

count - count of lookahead characters to consume

Throws:

IOException

getStreamPosition

public long getStreamPosition()
                       throws IOException

Throws:

IOException

getInBufPos

protected int getInBufPos()

getBufSize

protected int getBufSize()

fill

protected boolean fill()
                throws IOException

Throws:

IOException

getSizeEstimate

public long getSizeEstimate()

Description copied from class: SeekableInputStream

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

Specified by:

getSizeEstimate in class SeekableInputStream

Returns:

an estimated size