org.apache.cassandra.io.util

Class RewindableDataInputStreamPlus

java.lang.Object

java.io.InputStream

java.io.FilterInputStream

org.apache.cassandra.io.util.RewindableDataInputStreamPlus

All Implemented Interfaces:

java.io.Closeable, java.io.DataInput, java.lang.AutoCloseable, DataInputPlus, RewindableDataInput

public class RewindableDataInputStreamPlus
extends java.io.FilterInputStream
implements RewindableDataInput, java.io.Closeable

Adds mark/reset functionality to another input stream by caching read bytes to a memory buffer and spilling to disk if necessary. When the stream is marked via this#mark() or this#mark(int), up to maxMemBufferSize will be cached in memory (heap). If more than maxMemBufferSize bytes are read while the stream is marked, the following bytes are cached on the spillFile for up to maxDiskBufferSize. Please note that successive calls to this#mark() and this#reset() will write sequentially to the same spillFile until maxDiskBufferSize is reached. At this point, if less than maxDiskBufferSize bytes are currently cached on the spillFile, the remaining bytes are written to the beginning of the file, treating the spillFile as a circular buffer. If more than maxMemBufferSize + maxDiskBufferSize are cached while the stream is marked, the following this#reset() invocation will throw a IllegalStateException.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	RewindableDataInputStreamPlus.RewindableDataInputPlusMark

Nested classes/interfaces inherited from interface org.apache.cassandra.io.util.DataInputPlus

DataInputPlus.DataInputStreamPlus

Field Summary

Fields

Modifier and Type	Field and Description
protected int	diskHeadAvailable
protected int	diskTailAvailable
protected int	memAvailable

Fields inherited from class java.io.FilterInputStream

in

Constructor Summary

Constructors

Constructor and Description
RewindableDataInputStreamPlus(java.io.InputStream in, int initialMemBufferSize, int maxMemBufferSize, java.io.File spillFile, int maxDiskBufferSize)

Method Summary

Modifier and Type	Method and Description
int	available()
long	bytesPastMark(DataPosition mark)
void	close()
void	close(boolean closeUnderlying)
DataPosition	mark() Marks the current position of a stream to return to this position later via the this#reset(DataPosition) method.
void	mark(int readlimit) Marks the current position of a stream to return to this position later via the this#reset() method.
boolean	markSupported()
int	read()
int	read(byte[] b)
int	read(byte[] b, int off, int len)
boolean	readBoolean()
byte	readByte()
char	readChar()
double	readDouble()
float	readFloat()
void	readFully(byte[] b)
void	readFully(byte[] b, int off, int len)
int	readInt()
java.lang.String	readLine()
long	readLong()
short	readShort()
int	readUnsignedByte()
int	readUnsignedShort()
java.lang.String	readUTF()
void	reset()
void	reset(DataPosition mark) Rewinds to the previously marked position via the this#mark() method.
long	skip(long n)
int	skipBytes(int n) Always skips the requested number of bytes, unless EOF is reached

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.cassandra.io.util.DataInputPlus

readUnsignedVInt, readVInt, skipBytesFully

Field Detail

memAvailable

protected int memAvailable

diskTailAvailable

protected int diskTailAvailable

diskHeadAvailable

protected int diskHeadAvailable

Constructor Detail

RewindableDataInputStreamPlus

public RewindableDataInputStreamPlus(java.io.InputStream in,
                                     int initialMemBufferSize,
                                     int maxMemBufferSize,
                                     java.io.File spillFile,
                                     int maxDiskBufferSize)

Method Detail

mark

public DataPosition mark()

Marks the current position of a stream to return to this position later via the this#reset(DataPosition) method.

Specified by:

mark in interface RewindableDataInput

Returns:

An empty @link{DataPosition} object

reset

public void reset(DataPosition mark)
           throws java.io.IOException

Rewinds to the previously marked position via the this#mark() method.

Specified by:

reset in interface RewindableDataInput

Parameters:

mark - it's not possible to return to a custom position, so this parameter is ignored.

Throws:

java.io.IOException - if an error ocurs while resetting

bytesPastMark

public long bytesPastMark(DataPosition mark)

Specified by:

bytesPastMark in interface RewindableDataInput

markSupported

public boolean markSupported()

Overrides:

markSupported in class java.io.FilterInputStream

mark

public void mark(int readlimit)

Marks the current position of a stream to return to this position later via the this#reset() method.

Overrides:

mark in class java.io.FilterInputStream

Parameters:

readlimit - the maximum amount of bytes to cache

reset

public void reset()
           throws java.io.IOException

Overrides:

reset in class java.io.FilterInputStream

Throws:

java.io.IOException

available

public int available()
              throws java.io.IOException

Overrides:

available in class java.io.FilterInputStream

Throws:

java.io.IOException

read

public int read()
         throws java.io.IOException

Overrides:

read in class java.io.FilterInputStream

Throws:

java.io.IOException

read

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

Overrides:

read in class java.io.FilterInputStream

Throws:

java.io.IOException

read

public int read(byte[] b)
         throws java.io.IOException

Overrides:

read in class java.io.FilterInputStream

Throws:

java.io.IOException

skip

public long skip(long n)
          throws java.io.IOException

Overrides:

skip in class java.io.FilterInputStream

Throws:

java.io.IOException

close

public void close()
           throws java.io.IOException

Specified by:

close in interface java.io.Closeable

Specified by:

close in interface java.lang.AutoCloseable

Overrides:

close in class java.io.FilterInputStream

Throws:

java.io.IOException

close

public void close(boolean closeUnderlying)
           throws java.io.IOException

Throws:

java.io.IOException

readFully

public void readFully(byte[] b)
               throws java.io.IOException

Specified by:

readFully in interface java.io.DataInput

Throws:

java.io.IOException

readFully

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

Specified by:

readFully in interface java.io.DataInput

Throws:

java.io.IOException

skipBytes

public int skipBytes(int n)
              throws java.io.IOException

Description copied from interface: DataInputPlus

Always skips the requested number of bytes, unless EOF is reached

Specified by:

skipBytes in interface java.io.DataInput

Specified by:

skipBytes in interface DataInputPlus

Parameters:

n - number of bytes to skip

Returns:

number of bytes skipped

Throws:

java.io.IOException

readBoolean

public boolean readBoolean()
                    throws java.io.IOException

Specified by:

readBoolean in interface java.io.DataInput

Throws:

java.io.IOException

readByte

public byte readByte()
              throws java.io.IOException

Specified by:

readByte in interface java.io.DataInput

Throws:

java.io.IOException

readUnsignedByte

public int readUnsignedByte()
                     throws java.io.IOException

Specified by:

readUnsignedByte in interface java.io.DataInput

Throws:

java.io.IOException

readShort

public short readShort()
                throws java.io.IOException

Specified by:

readShort in interface java.io.DataInput

Throws:

java.io.IOException

readUnsignedShort

public int readUnsignedShort()
                      throws java.io.IOException

Specified by:

readUnsignedShort in interface java.io.DataInput

Throws:

java.io.IOException

readChar

public char readChar()
              throws java.io.IOException

Specified by:

readChar in interface java.io.DataInput

Throws:

java.io.IOException

readInt

public int readInt()
            throws java.io.IOException

Specified by:

readInt in interface java.io.DataInput

Throws:

java.io.IOException

readLong

public long readLong()
              throws java.io.IOException

Specified by:

readLong in interface java.io.DataInput

Throws:

java.io.IOException

readFloat

public float readFloat()
                throws java.io.IOException

Specified by:

readFloat in interface java.io.DataInput

Throws:

java.io.IOException

readDouble

public double readDouble()
                  throws java.io.IOException

Specified by:

readDouble in interface java.io.DataInput

Throws:

java.io.IOException

readLine

public java.lang.String readLine()
                          throws java.io.IOException

Specified by:

readLine in interface java.io.DataInput

Throws:

java.io.IOException

readUTF

public java.lang.String readUTF()
                         throws java.io.IOException

Specified by:

readUTF in interface java.io.DataInput

Throws:

java.io.IOException