QueryEngineHTTP (Apache Jena ARQ)

java.lang.Object
- org.apache.jena.sparql.engine.http.QueryEngineHTTP

All Implemented Interfaces:

AutoCloseable, QueryExecution
```
public class QueryEngineHTTP
extends Object
implements QueryExecution
```
A query execution implementation where queries are executed against a remote service

Field Summary

Fields
Modifier and Type	Field and Description
`static String`	`QUERY_MIME_TYPE`
`static String[]`	`supportedAskContentTypes` Supported content types for ASK queries
`static String[]`	`supportedSelectContentTypes` Supported content types for SELECT queries

Constructor Summary

Constructors
Constructor and Description
`QueryEngineHTTP(String serviceURI, Query query)`
`QueryEngineHTTP(String serviceURI, Query query, org.apache.http.client.HttpClient client)`
`QueryEngineHTTP(String serviceURI, Query query, org.apache.http.client.HttpClient client, org.apache.http.protocol.HttpContext httpContext)`
`QueryEngineHTTP(String serviceURI, String queryString)`
`QueryEngineHTTP(String serviceURI, String queryString, org.apache.http.client.HttpClient client)`
`QueryEngineHTTP(String serviceURI, String queryString, org.apache.http.client.HttpClient client, org.apache.http.protocol.HttpContext httpContext)`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`abort()` Stop in mid execution.
`void`	`addDefaultGraph(String defaultGraph)`
`void`	`addNamedGraph(String name)`
`void`	`addParam(String field, String value)`
`void`	`cancel()` Cancel query evaluation
`void`	`close()` Close the query execution and stop query evaluation as soon as convenient.
`static String`	`defaultAskHeader()`
`static String`	`defaultConstructDatasetHeader()`
`static String`	`defaultConstructHeader()`
`static String`	`defaultSelectHeader()`
`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'.
`Dataset`	`execConstructDataset()` Execute a CONSTRUCT query, putting the statements into 'dataset'.
`Dataset`	`execConstructDataset(Dataset dataset)` Execute a CONSTRUCT query, putting the statements into 'dataset'.
`Iterator<Quad>`	`execConstructQuads()` Execute a CONSTRUCT query, returning the results as an iterator of `Quad`.
`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`.
`JsonArray`	`execJson()` Execute a JSON query and return a json array
`Iterator<JsonObject>`	`execJsonItems()` Execute a JSON query and return an interator
`ResultSet`	`execSelect()` Execute a SELECT query
`String`	`getAcceptHeader()` Get the HTTP Accept header for the request.
`boolean`	`getAllowCompression()` Gets whether HTTP requests will indicate to the remote server that compressed encoding of responses is accepted
`org.apache.http.client.HttpClient`	`getClient()` Get the HTTP client in use, if none is set then null.
`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.
`org.apache.http.protocol.HttpContext`	`getHttpContext()` Get the HTTP context in use, if none is set then null.
`String`	`getHttpResponseContentType()` The Content-Type response header received (null before the remote operation is attempted).
`Query`	`getQuery()` The query associated with a query execution.
`String`	`getQueryString()` Return the query string.
`long`	`getTimeout1()` Return the first timeout (time to first result), in milliseconds: negative if unset
`long`	`getTimeout2()` Return the second timeout (overall query execution after first result), in milliseconds: negative if unset
`boolean`	`isClosed()` Answer whether this QueryExecution object has been closed or not.
`void`	`setAcceptHeader(String acceptHeader)` Set the HTTP Accept header for the request.
`void`	`setAllowCompression(boolean allowed)` Sets whether the HTTP requests will permit compressed encoding
`void`	`setAskContentType(String contentType)` Sets the Content Type for ASK queries provided that the format is supported
`void`	`setClient(org.apache.http.client.HttpClient client)` Sets the HTTP client to use, if none is set then the default client is used.
`void`	`setDatasetContentType(String contentType)`
`void`	`setDefaultGraphURIs(List<String> defaultGraphURIs)`
`void`	`setHttpContext(org.apache.http.protocol.HttpContext context)` Sets the HTTP context to use, if none is set then the default context is used.
`void`	`setInitialBinding(Binding binding)` Set the initial association of variables and values.
`void`	`setInitialBinding(QuerySolution binding)` Set the initial association of variables and values.
`void`	`setModelContentType(String contentType)` Sets the Content Type for CONSTRUCT/DESCRIBE queries provided that the format is supported
`void`	`setNamedGraphURIs(List<String> namedGraphURIs)`
`void`	`setSelectContentType(String contentType)` Sets the Content Type for SELECT queries provided that the format is supported
`void`	`setTimeout(long readTimeout)` Set time, in milliseconds
`void`	`setTimeout(long readTimeout, long connectTimeout)` Set time, in milliseconds
`void`	`setTimeout(long readTimeout, 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.
`String`	`toString()`

Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.jena.query.QueryExecution
create

- Field Detail
  - QUERY_MIME_TYPE
```
public static final String QUERY_MIME_TYPE
```
    See Also:
    
    Constant Field Values
  - supportedSelectContentTypes
```
public static String[] supportedSelectContentTypes
```
    Supported content types for SELECT queries
  - supportedAskContentTypes
```
public static String[] supportedAskContentTypes
```
    Supported content types for ASK queries
- Constructor Detail
  - QueryEngineHTTP
```
public QueryEngineHTTP(String serviceURI,
                       Query query)
```
  - QueryEngineHTTP
```
public QueryEngineHTTP(String serviceURI,
                       Query query,
                       org.apache.http.client.HttpClient client)
```
  - QueryEngineHTTP
```
public QueryEngineHTTP(String serviceURI,
                       Query query,
                       org.apache.http.client.HttpClient client,
                       org.apache.http.protocol.HttpContext httpContext)
```
  - QueryEngineHTTP
```
public QueryEngineHTTP(String serviceURI,
                       String queryString)
```
  - QueryEngineHTTP
```
public QueryEngineHTTP(String serviceURI,
                       String queryString,
                       org.apache.http.client.HttpClient client)
```
  - QueryEngineHTTP
```
public QueryEngineHTTP(String serviceURI,
                       String queryString,
                       org.apache.http.client.HttpClient client,
                       org.apache.http.protocol.HttpContext httpContext)
```
- Method Detail
  - setInitialBinding
```
public void setInitialBinding(QuerySolution binding)
```
    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
  - setInitialBinding
```
public void setInitialBinding(Binding binding)
```
    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
  - setDefaultGraphURIs
```
public void setDefaultGraphURIs(List<String> defaultGraphURIs)
```
    Parameters:
    
    defaultGraphURIs - The defaultGraphURIs to set.
  - setNamedGraphURIs
```
public void setNamedGraphURIs(List<String> namedGraphURIs)
```
    Parameters:
    
    namedGraphURIs - The namedGraphURIs to set.
  - setAllowCompression
```
public void setAllowCompression(boolean allowed)
```
    Sets whether the HTTP requests will permit compressed encoding
  - addParam
```
public void addParam(String field,
                     String value)
```
  - addDefaultGraph
```
public void addDefaultGraph(String defaultGraph)
```
    Parameters:
    
    defaultGraph - The defaultGraph to add.
  - addNamedGraph
```
public void addNamedGraph(String name)
```
    Parameters:
    
    name - The URI to add.
  - setClient
```
public void setClient(org.apache.http.client.HttpClient client)
```
    Sets the HTTP client to use, if none is set then the default client is used.
    
    Parameters:
    
    client - HTTP client
  - getClient
```
public org.apache.http.client.HttpClient getClient()
```
    Get the HTTP client in use, if none is set then null.
    
    Returns:
    
    client HTTP client
  - setHttpContext
```
public void setHttpContext(org.apache.http.protocol.HttpContext context)
```
    Sets the HTTP context to use, if none is set then the default context is used.
    
    Parameters:
    
    context - HTTP context
  - getHttpContext
```
public org.apache.http.protocol.HttpContext getHttpContext()
```
    Get the HTTP context in use, if none is set then null.
    
    Returns:
    
    the HttpContext in scope
  - getHttpResponseContentType
```
public String getHttpResponseContentType()
```
    The Content-Type response header received (null before the remote operation is attempted).
  - 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 cascaded 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.
  - execConstructQuads
```
public Iterator<Quad> execConstructQuads()
```
    Description copied from interface: QueryExecution
    
    Execute a CONSTRUCT query, returning the results as an iterator of Quad.
    Caution: This method may return duplicate Quads. 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.
    
    Specified by:
    
    execConstructQuads in interface QueryExecution
    
    Returns:
    
    An iterator of Quad objects (possibly containing duplicates) generated by applying the CONSTRUCT template of the query to the bindings in the WHERE clause.
    
    See QueryExecution.execConstructTriples() for usage and features.
  - execConstructDataset
```
public Dataset execConstructDataset()
```
    Description copied from interface: QueryExecution
    
    Execute a CONSTRUCT query, putting the statements into 'dataset'. This maybe an extended syntax query (if supported).
    
    Specified by:
    
    execConstructDataset in interface QueryExecution
  - execConstructDataset
```
public Dataset execConstructDataset(Dataset dataset)
```
    Description copied from interface: QueryExecution
    
    Execute a CONSTRUCT query, putting the statements into 'dataset'. This maybe an extended syntax query (if supported).
    
    Specified by:
    
    execConstructDataset in interface QueryExecution
  - 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
  - execJson
```
public JsonArray execJson()
```
    Description copied from interface: QueryExecution
    
    Execute a JSON query and return a json array
    
    Specified by:
    
    execJson in interface QueryExecution
  - execJsonItems
```
public Iterator<JsonObject> execJsonItems()
```
    Description copied from interface: QueryExecution
    
    Execute a JSON query and return an interator
    
    Specified by:
    
    execJsonItems in interface QueryExecution
  - 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
  - getQueryString
```
public String getQueryString()
```
    Return the query string. If this was supplied in a constructor, there is no guaranttee this is legal SPARQL syntax.
  - setTimeout
```
public void setTimeout(long readTimeout)
```
    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 readTimeout,
                       long connectTimeout)
```
    Description copied from interface: QueryExecution
    
    Set time, in milliseconds
    
    Specified by:
    
    setTimeout in interface QueryExecution
    
    See Also:
    
    QueryExecution.setTimeout(long, TimeUnit, long, TimeUnit)
  - setTimeout
```
public void setTimeout(long readTimeout,
                       TimeUnit timeoutUnits)
```
    Description copied from interface: QueryExecution
    
    Set a timeout on the query execution. Processing will be aborted after the timeout (which starts when the appropriate 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 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
  - getTimeout1
```
public long getTimeout1()
```
    Description copied from interface: QueryExecution
    
    Return the first timeout (time to first result), in milliseconds: 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 milliseconds: negative if unset
    
    Specified by:
    
    getTimeout2 in interface QueryExecution
  - getAllowCompression
```
public boolean getAllowCompression()
```
    Gets whether HTTP requests will indicate to the remote server that compressed encoding of responses is accepted
    
    Returns:
    
    True if compressed encoding will be accepted
  - cancel
```
public void cancel()
```
    Cancel query evaluation
  - 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
  - close
```
public void close()
```
    Description copied from interface: QueryExecution
    
    Close the query execution and stop query evaluation as soon as convenient. QueryExecution objects, and a ResultSet from QueryExecution.execSelect(), can not be used once the QueryExecution is closed. Model results from QueryExecution.execConstruct() and QueryExecution.execDescribe() are still valid. 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.
    
    Specified by:
    
    close in interface AutoCloseable
    
    Specified by:
    
    close in interface QueryExecution
  - isClosed
```
public boolean isClosed()
```
    Description copied from interface: QueryExecution
    
    Answer whether this QueryExecution object has been closed or not.
    
    Specified by:
    
    isClosed in interface QueryExecution
    
    Returns:
    
    boolean
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object
  - setSelectContentType
```
public void setSelectContentType(String contentType)
```
    Sets the Content Type for SELECT queries provided that the format is supported
    
    Parameters:
    
    contentType -
  - setAskContentType
```
public void setAskContentType(String contentType)
```
    Sets the Content Type for ASK queries provided that the format is supported
    
    Parameters:
    
    contentType -
  - setModelContentType
```
public void setModelContentType(String contentType)
```
    Sets the Content Type for CONSTRUCT/DESCRIBE queries provided that the format is supported
    
    Parameters:
    
    contentType -
  - setDatasetContentType
```
public void setDatasetContentType(String contentType)
```
  - defaultSelectHeader
```
public static String defaultSelectHeader()
```
  - defaultAskHeader
```
public static String defaultAskHeader()
```
  - defaultConstructHeader
```
public static String defaultConstructHeader()
```
  - defaultConstructDatasetHeader
```
public static String defaultConstructDatasetHeader()
```
  - getAcceptHeader
```
public String getAcceptHeader()
```
    Get the HTTP Accept header for the request.
  - setAcceptHeader
```
public void setAcceptHeader(String acceptHeader)
```
    Set the HTTP Accept header for the request. Unlike the set??ContentType operations, this is not checked for validity.

Class QueryEngineHTTP

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface org.apache.jena.query.QueryExecution

Field Detail

QUERY_MIME_TYPE

supportedSelectContentTypes

supportedAskContentTypes

Constructor Detail

QueryEngineHTTP

QueryEngineHTTP

QueryEngineHTTP

QueryEngineHTTP

QueryEngineHTTP

QueryEngineHTTP

Method Detail

setInitialBinding

setInitialBinding

setDefaultGraphURIs

setNamedGraphURIs

setAllowCompression

addParam

addDefaultGraph

addNamedGraph

setClient

getClient

setHttpContext

getHttpContext

getHttpResponseContentType

execSelect

execConstruct

execConstruct

execConstructTriples

execConstructQuads

execConstructDataset

execConstructDataset

execDescribe

execDescribe

execDescribeTriples

execAsk

execJson

execJsonItems

getContext

getDataset

getQuery

getQueryString

setTimeout

setTimeout

setTimeout

setTimeout

getTimeout1

getTimeout2

getAllowCompression

cancel

abort

close

isClosed

toString

setSelectContentType

setAskContentType

setModelContentType

setDatasetContentType

defaultSelectHeader

defaultAskHeader

defaultConstructHeader

defaultConstructDatasetHeader

getAcceptHeader

setAcceptHeader