/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.hp.hpl.jena.sparql.pfunction.library;
import com.hp.hpl.jena.graph.Node ;
import com.hp.hpl.jena.graph.NodeFactory ;
import com.hp.hpl.jena.query.QueryBuildException ;
import com.hp.hpl.jena.query.QueryException ;
import com.hp.hpl.jena.sparql.core.Var ;
import com.hp.hpl.jena.sparql.engine.ExecutionContext ;
import com.hp.hpl.jena.sparql.engine.QueryIterator ;
import com.hp.hpl.jena.sparql.engine.binding.Binding ;
import com.hp.hpl.jena.sparql.engine.binding.BindingFactory ;
import com.hp.hpl.jena.sparql.engine.binding.BindingMap ;
import com.hp.hpl.jena.sparql.pfunction.PropFuncArg ;
import com.hp.hpl.jena.sparql.pfunction.PropFuncArgType ;
import com.hp.hpl.jena.sparql.pfunction.PropertyFunctionEval ;
import org.apache.jena.atlas.logging.Log ;
import com.hp.hpl.jena.sparql.util.IterLib ;
import com.hp.hpl.jena.sparql.util.NodeUtils ;
import com.hp.hpl.jena.sparql.util.Utils ;
public class splitIRI extends PropertyFunctionEval //PropertyFunctionBase
{
public splitIRI()
{
super(PropFuncArgType.PF_ARG_SINGLE, PropFuncArgType.PF_ARG_LIST) ;
}
@Override
public void build(PropFuncArg argSubject, Node predicate, PropFuncArg argObject, ExecutionContext execCxt)
{
// Do some checking.
// These checks are assumed to be passed in .exec()
if ( argSubject.isList() )
throw new QueryBuildException(Utils.className(this)+ "Subject must be a single node or variable, not a list") ;
if ( ! argObject.isList() )
throw new QueryBuildException(Utils.className(this)+ "Object must be a list of two elements") ;
if ( argObject.getArgList().size() != 2 )
throw new QueryBuildException(Utils.className(this)+ "Object is a list but it has "+argObject.getArgList().size()+" elements - should be 2") ;
}
// Implementing .exec requires considering all the cases of variable being
// bound/constants or unbound variables. If an unexpected case arises, or
// one the implementation can't fulfil, then give warning and return
// QueryIterNullIterator or a null.
//
// Do not throw an exception except when an internal error situation occurs.
@Override
public QueryIterator execEvaluated(Binding binding, PropFuncArg argSubject, Node predicate, PropFuncArg argObject, ExecutionContext execCxt)
{
try {
// Subject bound to something other a URI.
if ( argSubject.getArg().isLiteral() || argSubject.getArg().isBlank() )
// Only split IRIs
return IterLib.noResults(execCxt) ;
if ( argSubject.getArg().isURI() )
// Case 1 : subject is a fixed URI or a variable bount to a URI.
return subjectIsIRI(argSubject.getArg(), argObject, binding, execCxt) ;
else
// Case 2 : subject is an unbound variable.
return subjectIsVariable(argSubject.getArg(), argObject, execCxt) ;
} catch (QueryException ex)
{
Log.warn(this, "Unexpected problems in splitIRI: "+ex.getMessage()) ;
return null ;
}
}
private QueryIterator subjectIsIRI(Node subject, PropFuncArg argObject, Binding binding, ExecutionContext execCxt)
{
String namespace = subject.getNameSpace() ;
String localname = subject.getLocalName() ;
Node namespaceNode = argObject.getArg(0) ;
Node localnameNode = argObject.getArg(1) ;
// New binding to return.
BindingMap b = null ;
if ( Var.isVar(namespaceNode) || Var.isVar(localnameNode) )
b = BindingFactory.create(binding) ;
if ( Var.isVar(namespaceNode) ) // .isVariable() )
{
b.add(Var.alloc(namespaceNode), NodeFactory.createURI(namespace)) ;
// Check for the case of (?x ?x) (very unlikely - and even more unlikely to cause a match)
// but it's possible for strange URI schemes.
if ( localnameNode.isVariable() && namespaceNode.getName() == localnameNode.getName() )
localnameNode = NodeFactory.createURI(namespace) ;
}
else
{
String ns = null ;
// Allow both IRIs and plain literals in the namespace position.
if ( namespaceNode.isURI() )
ns = namespaceNode.getURI() ;
if ( namespaceNode.isLiteral() )
ns = NodeUtils.stringLiteral(namespaceNode) ;
if ( ns == null || ! ns.equals(namespace) )
return IterLib.noResults(execCxt) ;
// Fall through and proceed to localname
}
if ( Var.isVar(localnameNode) )
b.add(Var.alloc(localnameNode), NodeFactory.createLiteral(localname)) ;
else
{
// Only string literals (plain strings or datatype xsd:string)
String lc = NodeUtils.stringLiteral(localnameNode) ;
if ( lc == null || ! lc.equals(localname) )
return IterLib.noResults(execCxt) ;
}
Binding b2 = ( b == null ) ? binding : b ;
return IterLib.result(b, execCxt) ;
}
private QueryIterator subjectIsVariable(Node arg, PropFuncArg argObject, ExecutionContext execCxt)
{
Log.warn(this, "Subject to property function splitURI is not a bound nor a constant.") ;
return IterLib.noResults(execCxt) ;
}
}