Package org.apache.lucene.store

Class IOContext

java.lang.Object

org.apache.lucene.store.IOContext

public class IOContext
extends Object

IOContext holds additional details on the merge/search context. A IOContext object can never be initialized as null as passed as a parameter to either Directory.openInput(String, IOContext) or Directory.createOutput(String, IOContext)

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	IOContext.Context	Context is a enumerator which specifies the context in which the Directory is being used for.

Field Summary

Fields

Modifier and Type	Field	Description
IOContext.Context	context	An object of a enumerator Context type
static IOContext	DEFAULT
FlushInfo	flushInfo
boolean	load	This flag is used for files that are a small fraction of the total index size and are expected to be heavily accessed in random-access fashion.
static IOContext	LOAD
MergeInfo	mergeInfo
static IOContext	RANDOM
boolean	randomAccess	This flag indicates that the file will be accessed randomly.
static IOContext	READ
boolean	readOnce	This flag indicates that the file will be opened, then fully read sequentially then closed.
static IOContext	READONCE

Constructor Summary

Constructors

Constructor	Description
IOContext()
IOContext(FlushInfo flushInfo)
IOContext(IOContext.Context context)
IOContext(IOContext ctxt, boolean readOnce)	This constructor is used to initialize a IOContext instance with a new value for the readOnce variable.
IOContext(MergeInfo mergeInfo)

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object obj)
int	hashCode()
String	toString()
IOContext	withRandomAccess()	Return an updated IOContext that has randomAccess set to true if context is IOContext.Context.READ or IOContext.Context.DEFAULT.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

context

public final IOContext.Context context

An object of a enumerator Context type

mergeInfo

public final MergeInfo mergeInfo

flushInfo

public final FlushInfo flushInfo

readOnce

public final boolean readOnce

This flag indicates that the file will be opened, then fully read sequentially then closed.

randomAccess

public final boolean randomAccess

This flag indicates that the file will be accessed randomly. If this flag is set, then readOnce will be false.

load

public final boolean load

This flag is used for files that are a small fraction of the total index size and are expected to be heavily accessed in random-access fashion. Some Directory implementations may choose to load such files into physical memory (e.g. Java heap) as a way to provide stronger guarantees on query latency. If this flag is set, then randomAccess will be true.

DEFAULT

public static final IOContext DEFAULT

READONCE

public static final IOContext READONCE

READ

public static final IOContext READ

LOAD

public static final IOContext LOAD

RANDOM

public static final IOContext RANDOM

Constructor Detail

IOContext

public IOContext()

IOContext

public IOContext(FlushInfo flushInfo)

IOContext

public IOContext(IOContext.Context context)

IOContext

public IOContext(MergeInfo mergeInfo)

IOContext

public IOContext(IOContext ctxt,
                 boolean readOnce)

This constructor is used to initialize a IOContext instance with a new value for the readOnce variable. This automatically sets randomAccess and load to false.

Parameters:

ctxt - IOContext object whose information is used to create the new instance except the readOnce variable.

readOnce - The new IOContext object will use this value for readOnce.

Method Detail

withRandomAccess

public IOContext withRandomAccess()

Return an updated IOContext that has randomAccess set to true if context is IOContext.Context.READ or IOContext.Context.DEFAULT. Otherwise, this returns this instance. This helps preserve sequential access for merging, which is always the right choice, while allowing IndexInputs open for searching to use random access.

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

toString

public String toString()

Overrides:

toString in class Object