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ARQ is a SPARQL 1.1 query engine for Apache Jena
/*
* 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 org.apache.jena.sparql.sse.builders;
import org.apache.jena.graph.Node ;
import org.apache.jena.sparql.core.Var ;
import org.apache.jena.sparql.engine.binding.Binding ;
import org.apache.jena.sparql.engine.binding.BindingFactory ;
import org.apache.jena.sparql.engine.binding.BindingMap ;
import org.apache.jena.sparql.sse.Item ;
import org.apache.jena.sparql.sse.ItemList ;
import org.apache.jena.sparql.sse.Tags ;
import org.apache.jena.sparql.util.FmtUtils ;
public class BuilderBinding
{
public static Binding build(Item item)
{
BuilderLib.checkList(item, "Attempt to build a binding from non-list: "+item) ;
return buildBinding(item.getList()) ;
}
private static Binding buildBinding(ItemList list)
{
// (row or (binding
if ( list.size() == 0 )
BuilderLib.broken(list, "Empty list") ;
Item head = list.get(0) ;
if ( ! head.isSymbolIgnoreCase(Tags.tagRow) && ! head.isSymbolIgnoreCase(Tags.tagBinding) )
BuilderLib.broken(list, "Does not start ("+Tags.tagRow+" ...) or ("+Tags.tagBinding+" ...)", head) ;
BindingMap binding = BindingFactory.create() ;
for ( int i = 1 ; i < list.size() ; i++ )
{
Item item = list.get(i) ;
BuilderLib.checkList(item, "Attempt to build a binding pair from non-list: "+item) ;
ItemList pair = item.getList() ;
BuilderLib.checkLength(2, pair, "Need a pair for a binding") ;
Var v = BuilderNode.buildVar(pair.get(0)) ;
Item cdr = pair.get(1) ;
// undef
if ( cdr.isSymbolIgnoreCase(Tags.tagUndef) || cdr.isSymbolIgnoreCase(Tags.tagNull) )
continue ;
Node node = BuilderNode.buildNode(item.getList().get(1)) ;
if ( node == null )
BuilderLib.broken(item.getList().get(1), "Null node from "+item.getList().get(1)) ;
if ( node.isVariable() )
BuilderLib.broken(item.getList().get(1), "No variables as table values: "+FmtUtils.stringForNode(node)) ;
if ( !node.isConcrete() )
BuilderLib.broken(item.getList().get(1), "Only concrete nodes as table values: "+FmtUtils.stringForNode(node)) ;
binding.add(v, node) ;
}
return binding ;
}
}