Package org.apache.jena.sparql.exec.http

Class QueryExecHTTP

  • All Implemented Interfaces:
    java.lang.AutoCloseable, QueryExec
    public class QueryExecHTTP
extends java.lang.Object
implements QueryExec
    A QueryExec implementation where queries are executed against a remote service over HTTP.

    • Constructor Detail

      • QueryExecHTTP

        public QueryExecHTTP​(java.lang.String serviceURL,
                     Query query,
                     java.lang.String queryString,
                     int urlLimit,
                     java.net.http.HttpClient httpClient,
                     java.util.Map<java.lang.String,​java.lang.String> httpHeaders,
                     Params params,
                     Context context,
                     java.util.List<java.lang.String> defaultGraphURIs,
                     java.util.List<java.lang.String> namedGraphURIs,
                     QuerySendMode sendMode,
                     java.lang.String explicitAcceptHeader,
                     long timeout,
                     java.util.concurrent.TimeUnit timeoutUnit)

    • Method Detail

      • getHttpResponseContentType

        public java.lang.String getHttpResponseContentType()
        The Content-Type response header received (null before the remote operation is attempted).

      • select

        public RowSet select()
        Description copied from interface: QueryExec
        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:
        select in interface QueryExec

      • ask

        public boolean ask()
        Description copied from interface: QueryExec
        Execute an ASK query
        Specified by:
        ask in interface QueryExec

      • construct

        public Graph construct​(Graph graph)
        Description copied from interface: QueryExec
        Execute a CONSTRUCT query, putting the statements into a graph.
        Specified by:
        construct in interface QueryExec
        Returns:
        Graph The graph argument for cascaded code.

      • constructTriples

        public java.util.Iterator<Triple> constructTriples()
        Description copied from interface: QueryExec
        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:
        constructTriples in interface QueryExec
        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.

      • constructQuads

        public java.util.Iterator<Quad> constructQuads()
        Description copied from interface: QueryExec
        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:
        constructQuads in interface QueryExec
        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 QueryExec.constructTriples() for usage and features.

      • constructDataset

        public DatasetGraph constructDataset()
        Description copied from interface: QueryExec
        Execute a CONSTRUCT query, putting the statements into 'dataset'. This maybe an extended syntax query (if supported).
        Specified by:
        constructDataset in interface QueryExec

      • constructDataset

        public DatasetGraph constructDataset​(DatasetGraph dataset)
        Description copied from interface: QueryExec
        Execute a CONSTRUCT query, putting the statements into 'dataset'. This may be an extended syntax query (if supported).
        Specified by:
        constructDataset in interface QueryExec

      • describe

        public Graph describe​(Graph graph)
        Description copied from interface: QueryExec
        Execute a DESCRIBE query, putting the statements into a graph.
        Specified by:
        describe in interface QueryExec
        Returns:
        Graph The model argument for cascaded code.

      • describeTriples

        public java.util.Iterator<Triple> describeTriples()
        Description copied from interface: QueryExec
        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:
        describeTriples in interface QueryExec
        Returns:
        An iterator of Triple objects (possibly containing duplicates) generated as the output of the DESCRIBE query.

      • execJson

        public JsonArray execJson()
        Description copied from interface: QueryExec
        Execute a JSON query and return a json array
        Specified by:
        execJson in interface QueryExec

      • execJsonItems

        public java.util.Iterator<JsonObject> execJsonItems()
        Description copied from interface: QueryExec
        Execute a JSON query and return an iterator
        Specified by:
        execJsonItems in interface QueryExec

      • getContext

        public Context getContext()
        Description copied from interface: QueryExec
        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 QueryExec

      • getDataset

        public DatasetGraph getDataset()
        Description copied from interface: QueryExec
        The dataset against which the query will execute. May be null - the dataset may be remote or the query itself has a dataset description.
        Specified by:
        getDataset in interface QueryExec

      • getQuery

        public Query getQuery()
        Description copied from interface: QueryExec
        The query associated with a query execution. May be null (QueryExec may have been created by other means)
        Specified by:
        getQuery in interface QueryExec

      • getQueryString

        public java.lang.String getQueryString()
        Return the query string. If this was supplied in a constructor, there is no guarantee this is legal SPARQL syntax.
        Specified by:
        getQueryString in interface QueryExec

      • cancel

        public void cancel()
        Cancel query evaluation

      • abort

        public void abort()
        Description copied from interface: QueryExec
        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 QueryExec

      • close

        public void close()
        Description copied from interface: QueryExec
        Close the query execution and stop query evaluation as soon as convenient. QExec objects, and a RowSet from QueryExec.select(), can not be used once the QExec is closed. Model results from QueryExec.construct() and QueryExec.describe() 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 java.lang.AutoCloseable
        Specified by:
        close in interface QueryExec

      • isClosed

        public boolean isClosed()
        Description copied from interface: QueryExec
        Answer whether this QueryExecution object has been closed or not.
        Specified by:
        isClosed in interface QueryExec
        Returns:
        boolean