Package org.apache.lucene.store

Class ChecksumIndexInput

java.lang.Object

org.apache.lucene.store.DataInput

org.apache.lucene.store.IndexInput

org.apache.lucene.store.ChecksumIndexInput

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable, java.lang.Cloneable

Direct Known Subclasses:

BufferedChecksumIndexInput, EndiannessReverserChecksumIndexInput

public abstract class ChecksumIndexInput
extends IndexInput

Extension of IndexInput, computing checksum as it goes. Callers can retrieve the checksum via getChecksum().

Field Summary

Fields

Modifier and Type	Field	Description
private static int	SKIP_BUFFER_SIZE
private byte[]	skipBuffer

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	ChecksumIndexInput(java.lang.String resourceDescription)	resourceDescription should be a non-null, opaque string describing this resource; it's returned from IndexInput.toString().

Method Summary

Modifier and Type	Method	Description
abstract long	getChecksum()	Returns the current checksum value
void	seek(long pos)	Sets current position in this file, where the next read will occur.
private void	skipByReading(long numBytes)	Skip over numBytes bytes.

Methods inherited from class org.apache.lucene.store.IndexInput

clone, close, getFilePointer, getFullSliceDescription, length, randomAccessSlice, skipBytes, slice, toString

Methods inherited from class org.apache.lucene.store.DataInput

readByte, readBytes, readBytes, readFloats, readInt, readInts, readLong, readLongs, readMapOfStrings, readSetOfStrings, readShort, readString, readVInt, readVLong, readZInt, readZLong

Methods inherited from class java.lang.Object

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

Field Detail

SKIP_BUFFER_SIZE

private static final int SKIP_BUFFER_SIZE

See Also:

Constant Field Values

skipBuffer

private byte[] skipBuffer

Constructor Detail

ChecksumIndexInput

protected ChecksumIndexInput(java.lang.String resourceDescription)

resourceDescription should be a non-null, opaque string describing this resource; it's returned from IndexInput.toString().

Method Detail

getChecksum

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

Returns the current checksum value

Throws:

java.io.IOException

seek

public void seek(long pos)
          throws java.io.IOException

Sets current position in this file, where the next read will occur. If this is beyond the end of the file then this will throw EOFException and then the stream is in an undetermined state.

ChecksumIndexInput can only seek forward and seeks are expensive since they imply to read bytes in-between the current position and the target position in order to update the checksum.

Specified by:

seek in class IndexInput

Throws:

java.io.IOException

See Also:

IndexInput.getFilePointer()

skipByReading

private void skipByReading(long numBytes)
                    throws java.io.IOException

Skip over numBytes bytes. The contract on this method is that it should have the same behavior as reading the same number of bytes into a buffer and discarding its content. Negative values of numBytes are not supported.

Throws:

java.io.IOException