Package org.eclipse.rdf4j.query.resultio.helpers

Class QueryResultCollector

java.lang.Object

org.eclipse.rdf4j.query.resultio.helpers.QueryResultCollector

All Implemented Interfaces:

BooleanQueryResultHandler, QueryResultHandler, TupleQueryResultHandler

public class QueryResultCollector
extends Object
implements TupleQueryResultHandler, BooleanQueryResultHandler

An implementation of the QueryResultHandler interface that is able to collect a single result from either Boolean or Tuple results simultaneously.

The Lists that are returned by this interface are immutable.

Author:

Peter Ansell

Constructor Summary

Constructors

Constructor	Description
QueryResultCollector()

Method Summary

Modifier and Type	Method	Description
void	endQueryResult()	Indicates the end of a sequence of solutions.
List<String>	getBindingNames()	Returns a collection of binding names collected.
List<BindingSet>	getBindingSets()
boolean	getBoolean()	If getHandledBoolean() returns true this method returns the boolean that was last found using handleBoolean(boolean)
boolean	getHandledBoolean()	Determines whether handleBoolean(boolean) was called for this collector.
boolean	getHandledTuple()	Determines whether endQueryResult() was called after the last calls to startQueryResult(List) and optionally calls to handleSolution(BindingSet).
List<String>	getLinks()
void	handleBoolean(boolean value)	Handles the specified boolean value.
void	handleLinks(List<String> linkUrls)	Handles the links elements which are present in SPARQL Results JSON and SPARQL Results XML documents in the header.
void	handleSolution(BindingSet bindingSet)	Handles a solution.
void	startQueryResult(List<String> bindingNames)	Indicates the start of a sequence of Solutions.

Methods inherited from class java.lang.Object

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

Constructor Details

QueryResultCollector

public QueryResultCollector()

Method Details

handleBoolean

public void handleBoolean(boolean value)
                   throws QueryResultHandlerException

Description copied from interface: QueryResultHandler

Handles the specified boolean value.

Specified by:

handleBoolean in interface QueryResultHandler

Parameters:

value - The boolean value to handle.

Throws:

QueryResultHandlerException - If there was an error during the handling of this value. This exception may be thrown if the QueryResultHandler.startQueryResult(List), QueryResultHandler.handleSolution(BindingSet) or QueryResultHandler.endQueryResult() methods were called before this method was called, and the handler cannot process both boolean and tuple results simultaneously.

startQueryResult

public void startQueryResult(List<String> bindingNames)
                      throws TupleQueryResultHandlerException

Description copied from interface: QueryResultHandler

Indicates the start of a sequence of Solutions. The supplied bindingNames are an indication of the values that are in the Solutions. For example, a SPARQL query like select ?X ?Y where { ?X ?P ?Y } will have binding names X and Y.

Specified by:

startQueryResult in interface QueryResultHandler

Parameters:

bindingNames - An ordered set of binding names.

Throws:

TupleQueryResultHandlerException - If there was an error during the starting of the query result handler. This exception may be thrown if the QueryResultHandler.handleBoolean(boolean) method was called before this method and the handler cannot process both boolean and tuple results simultaneously.

handleSolution

public void handleSolution(BindingSet bindingSet)
                    throws TupleQueryResultHandlerException

Description copied from interface: QueryResultHandler

Handles a solution.

Specified by:

handleSolution in interface QueryResultHandler

Parameters:

bindingSet - A single set of tuple results, with binding names bound to values. Each of the binding names in the solution must have previously been registered with the QueryResultHandler.startQueryResult(List) method.

Throws:

TupleQueryResultHandlerException - If there was an error during the handling of the query solution. This exception may be thrown if the QueryResultHandler.handleBoolean(boolean) method was called before this method and the handler cannot process both boolean and tuple results simultaneously.

endQueryResult

public void endQueryResult()
                    throws TupleQueryResultHandlerException

Description copied from interface: QueryResultHandler

Indicates the end of a sequence of solutions.

Specified by:

endQueryResult in interface QueryResultHandler

Throws:

TupleQueryResultHandlerException - If there was an error during the ending of the query result handler. This exception may be thrown if the QueryResultHandler.handleBoolean(boolean) method was called before this method and the handler cannot process both boolean and tuple results simultaneously.

handleLinks

public void handleLinks(List<String> linkUrls)
                 throws QueryResultHandlerException

Description copied from interface: QueryResultHandler

Handles the links elements which are present in SPARQL Results JSON and SPARQL Results XML documents in the header.

NOTE: If the format does not support links, it must silently ignore a call to this method.

An accumulating handler should accumulate these links.

Specified by:

handleLinks in interface QueryResultHandler

Parameters:

linkUrls - The URLs of the links to handle.

Throws:

QueryResultHandlerException - If there was an error handling the set of link URLs. This error is not thrown in cases where links are not supported.

See Also:

• "link"

getHandledBoolean

public boolean getHandledBoolean()

Determines whether handleBoolean(boolean) was called for this collector.

Returns:

True if there was a boolean handled by this collector.

getBoolean

public boolean getBoolean()
                   throws QueryResultHandlerException

If getHandledBoolean() returns true this method returns the boolean that was last found using handleBoolean(boolean)

If getHandledBoolean() returns false this method throws a QueryResultHandlerException indicating that a response could not be provided.

Returns:

The boolean value that was collected.

Throws:

QueryResultHandlerException - If there was no boolean value collected.

getHandledTuple

public boolean getHandledTuple()

Determines whether endQueryResult() was called after the last calls to startQueryResult(List) and optionally calls to handleSolution(BindingSet).

Returns:

True if there was a call to endQueryResult() after the last calls to startQueryResult(List) and handleSolution(BindingSet).

getBindingNames

public List<String> getBindingNames()
                             throws QueryResultHandlerException

Returns a collection of binding names collected.

Returns:

An immutable list of Strings that were collected as the binding names.

Throws:

QueryResultHandlerException - If the tuple results set was not successfully collected, as signalled by a call to endQueryResult().

getBindingSets

public List<BindingSet> getBindingSets()
                                throws QueryResultHandlerException

Returns:

An immutable list of BindingSets that were collected as the tuple results.

Throws:

QueryResultHandlerException - If the tuple results set was not successfully collected, as signalled by a call to endQueryResult().

getLinks

public List<String> getLinks()

Returns:

A list of links accumulated from calls to handleLinks(List).