Package org.apache.lucene.store

Class IndexOutput

java.lang.Object

org.apache.lucene.store.DataOutput

org.apache.lucene.store.IndexOutput

All Implemented Interfaces:

Closeable, AutoCloseable

Direct Known Subclasses:

ByteBuffersIndexOutput, OutputStreamIndexOutput, RateLimitedIndexOutput

public abstract class IndexOutput
extends DataOutput
implements Closeable

A DataOutput for appending data to a file in a Directory.

Instances of this class are not thread-safe.

See Also:

• Directory
• IndexInput

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	IndexOutput(String resourceDescription, String name)	Sole constructor.

Method Summary

Modifier and Type	Method	Description
final long	alignFilePointer(int alignmentBytes)	Aligns the current file pointer to multiples of alignmentBytes bytes to improve reads with mmap.
static final long	alignOffset(long offset, int alignmentBytes)	Aligns the given offset to multiples of alignmentBytes bytes by rounding up.
abstract void	close()	Closes this stream to further operations.
abstract long	getChecksum()	Returns the current checksum of bytes written so far
abstract long	getFilePointer()	Returns the current position in this file, where the next write will occur.
String	getName()	Returns the name used to create this IndexOutput.
String	toString()

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

copyBytes, writeByte, writeBytes, writeBytes, writeInt, writeLong, writeMapOfStrings, writeSetOfStrings, writeShort, writeString, writeVInt, writeVLong, writeZInt, writeZLong

Methods inherited from class java.lang.Object

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

Constructor Details

IndexOutput

protected IndexOutput(String resourceDescription,
 String name)

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

Method Details

getName

public String getName()

Returns the name used to create this IndexOutput. This is especially useful when using Directory.createTempOutput(java.lang.String, java.lang.String, org.apache.lucene.store.IOContext).

close

public abstract void close()
                    throws IOException

Closes this stream to further operations.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Throws:

IOException

getFilePointer

public abstract long getFilePointer()

Returns the current position in this file, where the next write will occur.

getChecksum

public abstract long getChecksum()
                          throws IOException

Returns the current checksum of bytes written so far

Throws:

IOException

toString

public String toString()

Overrides:

toString in class Object

alignFilePointer

public final long alignFilePointer(int alignmentBytes)
                            throws IOException

Aligns the current file pointer to multiples of alignmentBytes bytes to improve reads with mmap. This will write between 0 and (alignmentBytes-1) zero bytes using DataOutput.writeByte(byte).

Parameters:

alignmentBytes - the alignment to which it should forward file pointer (must be a power of 2)

Returns:

the new file pointer after alignment

Throws:

IOException

See Also:

• alignOffset(long, int)

alignOffset

public static final long alignOffset(long offset,
 int alignmentBytes)

Aligns the given offset to multiples of alignmentBytes bytes by rounding up. The alignment must be a power of 2.