Package org.eclipse.rdf4j.spring.resultcache

Class ReusableGraphQueryResult

java.lang.Object

org.eclipse.rdf4j.spring.resultcache.ReusableGraphQueryResult

All Implemented Interfaces:

AutoCloseable, Iterable<Statement>, CloseableIteration<Statement,QueryEvaluationException>, Iteration<Statement,QueryEvaluationException>, GraphQueryResult, QueryResult<Statement>, ThrowableRecorder

public class ReusableGraphQueryResult
extends Object
implements GraphQueryResult, ThrowableRecorder

Wrapper for a TupleQueryResult, allowing the result to be replayed. Not thread-safe. The wrapper copies the result data, consuming the original result fully on close().

Example:

 TupleQueryResult result = tupleQuery.execute();
 ReuseableTupleQueryResult reusable = new ReuseableTupleQueryResult(result);
 while (reusable.hasNext()) {
        reuseable.next();
 }
 reuseable.close();
 GraphQueryResult cached = reuseable.recreateGraphQueryResult();
 while (cached.hasNext()) {
        cached.next();
 }
 cached.close();

 

Since:

4.0.0

Author:

Florian Kleedorfer

Constructor Summary

Constructors

Constructor	Description
ReusableGraphQueryResult(GraphQueryResult result, BindingSet queryBindings)

Method Summary

Modifier and Type	Method	Description
boolean	canReuse()
void	close()	Closes this iteration, freeing any resources that it is holding.
void	forEach(Consumer<? super Statement> action)
Map<String,String>	getNamespaces()	Retrieves relevant namespaces from the query result.
boolean	hasNext()	Returns true if the query result has more elements.
Iterator<Statement>	iterator()
Statement	next()	Returns the next element in the query result.
boolean	queryBindingsAreIdentical(BindingSet candidate)
void	recordThrowable(Throwable t)
CachedGraphQueryResult	recreateGraphQueryResult()
void	remove()	Removes from the underlying collection the last element returned by the iteration (optional operation).
Spliterator<Statement>	spliterator()
Stream<Statement>	stream()	Convert the result elements to a Java Stream.

Methods inherited from class java.lang.Object

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

Constructor Detail

ReusableGraphQueryResult

public ReusableGraphQueryResult(GraphQueryResult result,
                                BindingSet queryBindings)

Method Detail

queryBindingsAreIdentical

public boolean queryBindingsAreIdentical(BindingSet candidate)

canReuse

public boolean canReuse()

recreateGraphQueryResult

public CachedGraphQueryResult recreateGraphQueryResult()

recordThrowable

public void recordThrowable(Throwable t)

Specified by:

recordThrowable in interface ThrowableRecorder

getNamespaces

public Map<String,String> getNamespaces()
                                       throws QueryEvaluationException

Description copied from interface: GraphQueryResult

Retrieves relevant namespaces from the query result.
The contents of the Map may be modified after it is returned, as the initial return may be performed when the first RDF Statement is encountered.

Specified by:

getNamespaces in interface GraphQueryResult

Returns:

a Map<String, String> object containing (prefix, namespace) pairs.

Throws:

QueryEvaluationException

iterator

public Iterator<Statement> iterator()

Specified by:

iterator in interface Iterable<Statement>

Specified by:

iterator in interface QueryResult<Statement>

close

public void close()
           throws QueryEvaluationException

Description copied from interface: CloseableIteration

Closes this iteration, freeing any resources that it is holding. If the iteration has already been closed then invoking this method has no effect.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface CloseableIteration<Statement,QueryEvaluationException>

Throws:

QueryEvaluationException

hasNext

public boolean hasNext()
                throws QueryEvaluationException

Description copied from interface: QueryResult

Returns true if the query result has more elements. (In other words, returns true if QueryResult.next() would return an element rather than throwing a NoSuchElementException.)

Specified by:

hasNext in interface Iteration<Statement,QueryEvaluationException>

Specified by:

hasNext in interface QueryResult<Statement>

Returns:

true if the iteration has more elements.

Throws:

QueryEvaluationException - if an error occurs while executing the query.

next

public Statement next()
               throws QueryEvaluationException

Description copied from interface: QueryResult

Returns the next element in the query result.

Specified by:

next in interface Iteration<Statement,QueryEvaluationException>

Specified by:

next in interface QueryResult<Statement>

Returns:

the next element in the query result.

Throws:

QueryEvaluationException - if an error occurs while executing the query.

remove

public void remove()
            throws QueryEvaluationException

Description copied from interface: Iteration

Removes from the underlying collection the last element returned by the iteration (optional operation). This method can be called only once per call to next.

Specified by:

remove in interface Iteration<Statement,QueryEvaluationException>

Throws:

QueryEvaluationException

stream

public Stream<Statement> stream()

Description copied from interface: QueryResult

Convert the result elements to a Java Stream. Note that the consumer should take care to close the stream (by calling Stream#close() or using try-with-resource) if it is not fully consumed.

Specified by:

stream in interface CloseableIteration<Statement,QueryEvaluationException>

Specified by:

stream in interface Iteration<Statement,QueryEvaluationException>

Specified by:

stream in interface QueryResult<Statement>

Returns:

stream a Stream of query result elements.

forEach

public void forEach(Consumer<? super Statement> action)

Specified by:

forEach in interface Iterable<Statement>

spliterator

public Spliterator<Statement> spliterator()

Specified by:

spliterator in interface Iterable<Statement>