com.hp.hpl.jena.rdql
Class Query

java.lang.Object
  com.hp.hpl.jena.rdql.Query

public class Query

extends java.lang.Object

The data structure for a query. There are two ways of creating a query - use the parser to turn a string description of the query into the executable form, and the programmatic way (the parser is calling the programmatic operations driven by the quyery string). The declarative approach of passing in a string is preferred. Once a query is built, it can be passed to a query engine.

Version:

$Id: Query.java,v 1.9 2003/07/15 13:26:58 andy_seaborne Exp $

Author:

Andy Seaborne

See Also:

QueryEngine, QueryResults

Field Summary

long	buildTime
long	executeTime
long	loadTime
long	parseTime

Constructor Summary

Query()
Create a blank query.

Query(java.lang.String s)
Create a query from the given string by calling the parser.

Method Summary

void	addBoundVar(java.lang.String varName) Programmatic API operation
void	addConstraint(Constraint c) Programmatic API operation
void	addResultVar(java.lang.String varName) Programmatic API operation
void	addTriplePattern(Node s, Node p, Node o)
void	addTriplePattern(Triple t) Programmatic API operation
static QueryResults	exec(java.lang.String queryString) Convenience function to parse and execute a query.
static QueryResults	exec(java.lang.String queryString, Model model) Convenience function to parse and execute a query against an existing model.
static QueryResults	exec(java.lang.String queryString, java.lang.String dataURL) Convenience function to parse and execute a query against a remote model.
java.util.List	getBoundVars() Programmatic API operation
java.lang.String	getPrefix(java.lang.String prefix) Lookup a prefix for this query, including the default prefixes
java.util.List	getResultVars() Programmatic API operation
Model	getSource() Return the model that this query executes against.
java.lang.String	getSourceURL()
java.util.List	getTriplePatterns() Programmatic API operation
void	setPrefix(java.lang.String prefix, java.lang.String expansion) Set a prefix for this query
void	setSource(Model m) The data target for the query as a Jena model.
void	setSourceURL(java.lang.String s) Location of the source for the data.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

parseTime

public long parseTime

buildTime

public long buildTime

loadTime

public long loadTime

executeTime

public long executeTime

Constructor Detail

Query

public Query(java.lang.String s)

Create a query from the given string by calling the parser. After it has been created, an application should set the data source, then call the QueryEngine.

Parameters:

s - The query string

Throws:

QueryException - Thrown when a parse error occurs

Query

public Query()

Create a blank query. The application is expected to complete the query parts needed by calling the various "add" operations later,

Method Detail

exec

public static QueryResults exec(java.lang.String queryString)

Convenience function to parse and execute a query.

Parameters:

queryString - The query: should include FROM clause to provide the data

Throws:

QueryException - Runtime exception

exec

public static QueryResults exec(java.lang.String queryString,
                                Model model)

Convenience function to parse and execute a query against an existing model.

Parameters:

queryString - The query: the FROM clause will be overridden

model - The data

Throws:

QueryException - Runtime exception

exec

public static QueryResults exec(java.lang.String queryString,
                                java.lang.String dataURL)

Convenience function to parse and execute a query against a remote model. The remote data is loaded into the local application.

Parameters:

queryString - The query: the FROM clause will be overridden

dataURL - The remote data source

Throws:

QueryException - Runtime exception

setSource

public void setSource(Model m)

The data target for the query as a Jena model. Applications must call this whther using the parser or not.

getSource

public Model getSource()

Return the model that this query executes against.

setSourceURL

public void setSourceURL(java.lang.String s)

Location of the source for the data. If the model is not set, then the QueryEngine will attempt to load the data from this URL.

getSourceURL

public java.lang.String getSourceURL()

getResultVars

public java.util.List getResultVars()

Programmatic API operation

addResultVar

public void addResultVar(java.lang.String varName)

Programmatic API operation

getBoundVars

public java.util.List getBoundVars()

Programmatic API operation

addBoundVar

public void addBoundVar(java.lang.String varName)

Programmatic API operation

addConstraint

public void addConstraint(Constraint c)

Programmatic API operation

addTriplePattern

public void addTriplePattern(Triple t)

Programmatic API operation

addTriplePattern

public void addTriplePattern(Node s,
                             Node p,
                             Node o)

getTriplePatterns

public java.util.List getTriplePatterns()

Programmatic API operation

setPrefix

public void setPrefix(java.lang.String prefix,
                      java.lang.String expansion)

Set a prefix for this query

getPrefix

public java.lang.String getPrefix(java.lang.String prefix)

Lookup a prefix for this query, including the default prefixes

toString

public java.lang.String toString()