Package org.apache.lucene.index

Class IndexReaderContext

java.lang.Object

org.apache.lucene.index.IndexReaderContext

Direct Known Subclasses:

CompositeReaderContext, LeafReaderContext

public abstract class IndexReaderContext
extends Object

A struct like class that represents a hierarchical relationship between IndexReader instances.

Field Summary

Fields

Modifier and Type	Field	Description
int	docBaseInParent	the doc base for this reader in the parent, 0 if parent is null
boolean	isTopLevel	true if this context struct represents the top level reader within the hierarchical context
int	ordInParent	the ord for this reader in the parent, 0 if parent is null
CompositeReaderContext	parent	The reader context for this reader's immediate parent, or null if none

Method Summary

Modifier and Type	Method	Description
abstract List<IndexReaderContext>	children()	Returns the context's children iff this context is a composite context otherwise null .
Object	id()	Expert: Return an Object that uniquely identifies this context.
abstract List<LeafReaderContext>	leaves()	Returns the context's leaves if this context is a top-level context.
abstract IndexReader	reader()	Returns the IndexReader, this context represents.

Methods inherited from class java.lang.Object

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

Field Detail

parent

public final CompositeReaderContext parent

The reader context for this reader's immediate parent, or null if none

isTopLevel

public final boolean isTopLevel

true if this context struct represents the top level reader within the hierarchical context

docBaseInParent

public final int docBaseInParent

the doc base for this reader in the parent, 0 if parent is null

ordInParent

public final int ordInParent

the ord for this reader in the parent, 0 if parent is null

Method Detail

id

public Object id()

Expert: Return an Object that uniquely identifies this context. The returned object does neither reference this IndexReaderContext nor the wrapped IndexReader.

WARNING: This API is experimental and might change in incompatible ways in the next release.

reader

public abstract IndexReader reader()

Returns the IndexReader, this context represents.

leaves

public abstract List<LeafReaderContext> leaves()
                                        throws UnsupportedOperationException

Returns the context's leaves if this context is a top-level context. For convenience, if this is an LeafReaderContext this returns itself as the only leaf, and it will never return a null value.

Note: this is convenience method since leaves can always be obtained by walking the context tree using children().

Throws:

UnsupportedOperationException - if this is not a top-level context.

See Also:

children()

children

public abstract List<IndexReaderContext> children()

Returns the context's children iff this context is a composite context otherwise null .