QueryExecution (Apache Jena ARQ)

All Known Implementing Classes:

QueryEngineHTTP, QueryExecutionBase
```
public interface QueryExecution
```
A interface for a single execution of a query.

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.
`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 binding)` Set the initial association of variables and values.
`void`	`setTimeout(long timeout)` Set time, in milliseconds
`void`	`setTimeout(long timeout1, long timeout2)` Set time, in milliseconds
`void`	`setTimeout(long timeout, TimeUnit timeoutUnits)` 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.

- Method Detail
  - setFileManager
```
void setFileManager(FileManager fm)
```
    Set the FileManger that might be used to load files. May not be supported by all QueryExecution implementations.
  - setInitialBinding
```
void setInitialBinding(QuerySolution binding)
```
    Set the initial association of variables and values. May not be supported by all QueryExecution implementations.
    
    Parameters:
    binding -
  - getDataset
```
Dataset getDataset()
```
    The dataset against which the query will execute. May be null, implying it is expected that the query itself has a dataset description.
  - getContext
```
Context getContext()
```
    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).
  - getQuery
```
Query getQuery()
```
    The query associated with a query execution. May be null (QueryExecution may have been created by other means)
  - execSelect
```
ResultSet execSelect()
```
    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.
  - execConstruct
```
Model execConstruct()
```
    Execute a CONSTRUCT query
  - execConstruct
```
Model execConstruct(Model model)
```
    Execute a CONSTRUCT query, putting the statements into 'model'.
    
    Returns:
    Model The model argument for casaded code.
  - execConstructTriples
```
Iterator<Triple> execConstructTriples()
```
    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.
    
    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
```
Model execDescribe()
```
    Execute a DESCRIBE query
  - execDescribe
```
Model execDescribe(Model model)
```
    Execute a DESCRIBE query, putting the statements into 'model'.
    
    Returns:
    Model The model argument for cascaded code.
  - execDescribeTriples
```
Iterator<Triple> execDescribeTriples()
```
    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.
    
    Returns:
    An iterator of Triple objects (possibly containing duplicates) generated as the output of the DESCRIBE query.
  - execAsk
```
boolean execAsk()
```
    Execute an ASK query
  - abort
```
void abort()
```
    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.
  - close
```
void close()
```
    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.
  - setTimeout
```
void setTimeout(long timeout,
              TimeUnit timeoutUnits)
```
    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.
  - setTimeout
```
void setTimeout(long timeout)
```
    Set time, in milliseconds
    
    See Also:
    setTimeout(long, TimeUnit)
  - setTimeout
```
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. 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.
  - setTimeout
```
void setTimeout(long timeout1,
              long timeout2)
```
    Set time, in milliseconds
    
    See Also:
    setTimeout(long, TimeUnit, long, TimeUnit)
  - getTimeout1
```
long getTimeout1()
```
    Return the first timeout (time to first result), in millseconds: negative if unset
  - getTimeout2
```
long getTimeout2()
```
    Return the second timeout (overall query execution after first result), in millseconds: negative if unset

Interface QueryExecution

Method Summary

Method Detail

setFileManager

setInitialBinding

getDataset

getContext

getQuery

execSelect

execConstruct

execConstruct

execConstructTriples

execDescribe

execDescribe

execDescribeTriples

execAsk

abort

close

setTimeout

setTimeout

setTimeout

setTimeout

getTimeout1

getTimeout2