Package org.eclipse.rdf4j.query.algebra.evaluation

Class QueryContext

java.lang.Object

org.eclipse.rdf4j.query.algebra.evaluation.QueryContext

public class QueryContext
extends Object

A QueryContext provides a means to pass arbitrary local state to a Function or TupleFunction. The implementation of org.eclipse.rdf4j.sail.SailConnection#evaluate() is responsible for initialising a QueryContext and making it available during evaluation via QueryContextIteration. A QueryContext is commonly used to provide a QueryPreparer for the current SailConnection. This allows, for example, Functions to be written that conveniently express more complex queries.

Constructor Summary

Constructors

Constructor	Description
QueryContext()
QueryContext(QueryPreparer qp)

Method Summary

Modifier and Type	Method	Description
void	begin()
void	end()
<T> T	getAttribute(String name)
static QueryContext	getQueryContext()
QueryPreparer	getQueryPreparer()
void	setAttribute(String name, Object value)

Methods inherited from class java.lang.Object

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

Constructor Details

QueryContext

public QueryContext()

QueryContext

public QueryContext(QueryPreparer qp)

Method Details

getQueryContext

public static QueryContext getQueryContext()

begin

public void begin()

getQueryPreparer

public QueryPreparer getQueryPreparer()

setAttribute

public void setAttribute(String name,
 Object value)

getAttribute

public <T> T getAttribute(String name)

end

public void end()