Package org.apache.jena.sparql.engine.iterator

Class QueryIterRoot

java.lang.Object

org.apache.jena.sparql.util.PrintSerializableBase

org.apache.jena.sparql.engine.iterator.QueryIteratorBase

org.apache.jena.sparql.engine.iterator.QueryIter

org.apache.jena.sparql.engine.iterator.QueryIterYieldN

org.apache.jena.sparql.engine.iterator.QueryIterRoot

All Implemented Interfaces:

java.util.Iterator<Binding>, org.apache.jena.atlas.io.Printable, org.apache.jena.atlas.lib.Closeable, QueryIterator, PrintSerializable

public class QueryIterRoot
extends QueryIterYieldN

The root binding is one-row, usually no columns making it the join identity. It has columns only for an initial binding. It is useful to be able to spot it before having to activate a QueryIterator. Executing with a pre-set binding does not use QueryIterRoot.

Field Summary

Fields inherited from class org.apache.jena.sparql.engine.iterator.QueryIteratorBase

traceIterators

Method Summary

Modifier and Type	Method	Description
static QueryIterator	create(Binding binding, ExecutionContext execCxt)	Create a root with an initial binding
static QueryIterator	create(ExecutionContext execCxt)	Create a root
boolean	isJoinIdentity()
void	output(org.apache.jena.atlas.io.IndentedWriter out, SerializationContext sCxt)

Methods inherited from class org.apache.jena.sparql.engine.iterator.QueryIterYieldN

getBinding

Methods inherited from class org.apache.jena.sparql.engine.iterator.QueryIter

close, getExecContext, getIteratorNumber, makeTracked, map, materialize, materialize, output

Methods inherited from class org.apache.jena.sparql.engine.iterator.QueryIteratorBase

cancel, debug, hasNext, next, nextBinding, remove

Methods inherited from class org.apache.jena.sparql.util.PrintSerializableBase

toString, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Iterator

forEachRemaining

Methods inherited from interface org.apache.jena.sparql.util.PrintSerializable

toString

Method Detail

create

public static QueryIterator create(ExecutionContext execCxt)

Create a root

create

public static QueryIterator create(Binding binding,
                                   ExecutionContext execCxt)

Create a root with an initial binding

output

public void output(org.apache.jena.atlas.io.IndentedWriter out,
                   SerializationContext sCxt)

Specified by:

output in interface PrintSerializable

Overrides:

output in class QueryIterYieldN

isJoinIdentity

public boolean isJoinIdentity()