com.hp.hpl.jena.sparql.engine

Class QueryExecutionBase

java.lang.Object

com.hp.hpl.jena.sparql.engine.QueryExecutionBase

All Implemented Interfaces:

QueryExecution

public class QueryExecutionBase
extends Object
implements QueryExecution

All the SPARQL query result forms made from a graph-level execution object

Constructor Summary

Constructors

Constructor and Description
QueryExecutionBase(Query query, Dataset dataset, Context context, QueryEngineFactory qeFactory)

Method Summary

Methods

Modifier and Type	Method and Description
void	abort() Stop in mid execution.
void	close() Close the query execution and stop query evaluation as soon as convenient.
boolean	execAsk() Execute an ASK query
Model	execConstruct() Execute a CONSTRUCT query
Model	execConstruct(Model model) Execute a CONSTRUCT query, putting the statements into 'model'.
Iterator<Triple>	execConstructTriples() Execute a CONSTRUCT query, returning the results as an iterator of Triple.
Model	execDescribe() Execute a DESCRIBE query
Model	execDescribe(Model model) Execute a DESCRIBE query, putting the statements into 'model'.
Iterator<Triple>	execDescribeTriples() Execute a DESCRIBE query, returning the results as an iterator of Triple.
ResultSet	execSelect() Execute a SELECT query
Context	getContext() The properties associated with a query execution - implementation specific parameters This includes Java objects (so it is not an RDF graph).
Dataset	getDataset() The dataset against which the query will execute.
Plan	getPlan()
Query	getQuery() The query associated with a query execution.
long	getTimeout1() Return the first timeout (time to first result), in millseconds: negative if unset
long	getTimeout2() Return the second timeout (overall query execution after first result), in millseconds: negative if unset
void	setFileManager(FileManager fm) Set the FileManger that might be used to load files.
void	setInitialBinding(QuerySolution startSolution) Set the initial association of variables and values.
void	setInitialBindings(ResultSet table)
void	setTimeout(long timeout) Set time, in milliseconds
void	setTimeout(long timeout1, long timeout2) Set time, in milliseconds
void	setTimeout(long timeout, TimeUnit timeUnit) Set a timeout on the query execution.
void	setTimeout(long timeout1, TimeUnit timeUnit1, long timeout2, TimeUnit timeUnit2) Set timeouts on the query execution; the first timeout refers to time to first result, the second refers to overall query execution after the first result.
static Context	setupContext(Context context, DatasetGraph dataset)

Methods inherited from class java.lang.Object

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

Constructor Detail

QueryExecutionBase

public QueryExecutionBase(Query query,
                  Dataset dataset,
                  Context context,
                  QueryEngineFactory qeFactory)

Method Detail

setupContext

public static Context setupContext(Context context,
                   DatasetGraph dataset)

close

public void close()

Description copied from interface: QueryExecution

Close the query execution and stop query evaluation as soon as convenient. It is important to close query execution objects in order to release resources such as working memory and to stop the query execution. Some storage subsystems require explicit ends of operations and this operation will cause those to be called where necessary. No operations on the query execution or any associated result set are permitted after this call. This method should not be called in parallel with other methods on the QueryExecution object.

Specified by:

close in interface QueryExecution

abort

public void abort()

Description copied from interface: QueryExecution

Stop in mid execution. This method can be called in parallel with other methods on the QueryExecution object. There is no guarantee that the concrete implementation actual will stop or that it will do so immediately. No operations on the query execution or any associated result set are permitted after this call and may cause exceptions to be thrown.

Specified by:

abort in interface QueryExecution

execSelect

public ResultSet execSelect()

Description copied from interface: QueryExecution

Execute a SELECT query

Important: The name of this method is somewhat of a misnomer in that depending on the underlying implementation this typically does not execute the SELECT query but rather answers a wrapper over an internal data structure that can be used to answer the query. In essence calling this method only returns a plan for executing this query which only gets evaluated when you actually start iterating over the results.

Specified by:

execSelect in interface QueryExecution

execConstruct

public Model execConstruct()

Description copied from interface: QueryExecution

Execute a CONSTRUCT query

Specified by:

execConstruct in interface QueryExecution

execConstruct

public Model execConstruct(Model model)

Description copied from interface: QueryExecution

Execute a CONSTRUCT query, putting the statements into 'model'.

Specified by:

execConstruct in interface QueryExecution

Returns:

Model The model argument for casaded code.

execConstructTriples

public Iterator<Triple> execConstructTriples()

Description copied from interface: QueryExecution

Execute a CONSTRUCT query, returning the results as an iterator of Triple.

Caution: This method may return duplicate Triples. This method may be useful if you only need the results for stream processing, as it can avoid having to place the results in a Model.

Important: The name of this method is somewhat of a misnomer in that depending on the underlying implementation this typically does not execute the CONSTRUCT query but rather answers a wrapper over an internal data structure that can be used to answer the query. In essence calling this method only returns a plan for executing this query which only gets evaluated when you actually start iterating over the results.

Specified by:

execConstructTriples in interface QueryExecution

Returns:

An iterator of Triple objects (possibly containing duplicates) generated by applying the CONSTRUCT template of the query to the bindings in the WHERE clause.

execDescribe

public Model execDescribe()

Description copied from interface: QueryExecution

Execute a DESCRIBE query

Specified by:

execDescribe in interface QueryExecution

execDescribe

public Model execDescribe(Model model)

Description copied from interface: QueryExecution

Execute a DESCRIBE query, putting the statements into 'model'.

Specified by:

execDescribe in interface QueryExecution

Returns:

Model The model argument for cascaded code.

execDescribeTriples

public Iterator<Triple> execDescribeTriples()

Description copied from interface: QueryExecution

Execute a DESCRIBE query, returning the results as an iterator of Triple.

Caution: This method may return duplicate Triples. This method may be useful if you only need the results for stream processing, as it can avoid having to place the results in a Model.

Important: The name of this method is somewhat of a misnomer in that depending on the underlying implementation this typically does not execute the DESCRIBE query but rather answers a wrapper over an internal data structure that can be used to answer the query. In essence calling this method only returns a plan for executing this query which only gets evaluated when you actually start iterating over the results.

Specified by:

execDescribeTriples in interface QueryExecution

Returns:

An iterator of Triple objects (possibly containing duplicates) generated as the output of the DESCRIBE query.

execAsk

public boolean execAsk()

Description copied from interface: QueryExecution

Execute an ASK query

Specified by:

execAsk in interface QueryExecution

setTimeout

public void setTimeout(long timeout,
              TimeUnit timeUnit)

Description copied from interface: QueryExecution

Set a timeout on the query execution. Processing will be aborted after the timeout (which starts when the approprate exec call is made). Not all query execution systems support timeouts. A timeout of less than zero means no timeout.

Specified by:

setTimeout in interface QueryExecution

setTimeout

public void setTimeout(long timeout)

Description copied from interface: QueryExecution

Set time, in milliseconds

Specified by:

setTimeout in interface QueryExecution

See Also:

QueryExecution.setTimeout(long, TimeUnit)

setTimeout

public void setTimeout(long timeout1,
              TimeUnit timeUnit1,
              long timeout2,
              TimeUnit timeUnit2)

Description copied from interface: QueryExecution

Set timeouts on the query execution; the first timeout refers to time to first result, the second refers to overall query execution after the first result. Processing will be aborted if a timeout expires. Not all query execution systems support timeouts. A timeout of less than zero means no timeout; this can be used for timeout1 or timeout2.

Specified by:

setTimeout in interface QueryExecution

setTimeout

public void setTimeout(long timeout1,
              long timeout2)

Description copied from interface: QueryExecution

Set time, in milliseconds

Specified by:

setTimeout in interface QueryExecution

See Also:

QueryExecution.setTimeout(long, TimeUnit, long, TimeUnit)

getTimeout1

public long getTimeout1()

Description copied from interface: QueryExecution

Return the first timeout (time to first result), in millseconds: negative if unset

Specified by:

getTimeout1 in interface QueryExecution

getTimeout2

public long getTimeout2()

Description copied from interface: QueryExecution

Return the second timeout (overall query execution after first result), in millseconds: negative if unset

Specified by:

getTimeout2 in interface QueryExecution

getPlan

public Plan getPlan()

getContext

public Context getContext()

Description copied from interface: QueryExecution

The properties associated with a query execution - implementation specific parameters This includes Java objects (so it is not an RDF graph). Keys should be URIs as strings. May be null (this implementation does not provide any configuration).

Specified by:

getContext in interface QueryExecution

getDataset

public Dataset getDataset()

Description copied from interface: QueryExecution

The dataset against which the query will execute. May be null, implying it is expected that the query itself has a dataset description.

Specified by:

getDataset in interface QueryExecution

getQuery

public Query getQuery()

Description copied from interface: QueryExecution

The query associated with a query execution. May be null (QueryExecution may have been created by other means)

Specified by:

getQuery in interface QueryExecution

setFileManager

public void setFileManager(FileManager fm)

Description copied from interface: QueryExecution

Set the FileManger that might be used to load files. May not be supported by all QueryExecution implementations.

Specified by:

setFileManager in interface QueryExecution

setInitialBinding

public void setInitialBinding(QuerySolution startSolution)

Description copied from interface: QueryExecution

Set the initial association of variables and values. May not be supported by all QueryExecution implementations.

Specified by:

setInitialBinding in interface QueryExecution

setInitialBindings

public void setInitialBindings(ResultSet table)