/*
* 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.sse.builders;
import java.util.List ;
import com.hp.hpl.jena.sparql.algebra.Table ;
import com.hp.hpl.jena.sparql.algebra.TableFactory ;
import com.hp.hpl.jena.sparql.core.Var ;
import com.hp.hpl.jena.sparql.engine.binding.Binding ;
import com.hp.hpl.jena.sparql.sse.Item ;
import com.hp.hpl.jena.sparql.sse.ItemList ;
import com.hp.hpl.jena.sparql.sse.Tags ;
public class BuilderTable
{
public static Table build(Item item)
{
BuilderLib.checkTagged(item, Tags.tagTable, "Not a (table ...)") ;
ItemList list = item.getList() ;
int start = 1 ;
if ( list.size() == 1 )
// Null table;
return TableFactory.createEmpty() ;
// Maybe vars.
List<Var> vars = null ;
if ( list.size() > 1 )
{
Item item0 = list.get(1) ;
if ( item0.isTagged(Tags.tagVars) )
{
vars = BuilderNode.buildVarList(item0) ;
list = list.cdr() ;
}
}
if ( list.size() == 2 && list.get(1).isSymbol() )
{
// Short hand for well known tables
String symbol = list.get(1).getSymbol() ;
if ( symbol.equals("unit") )
return TableFactory.createUnit() ;
if ( symbol.equals("empty") )
return TableFactory.createEmpty() ;
BuilderLib.broken(list, "Don't recognized table symbol") ;
}
Table table = TableFactory.create(vars) ;
int count = 0 ;
Binding lastBinding = null ;
for ( int i = start ; i < list.size() ; i++ )
{
Item itemRow = list.get(i) ;
Binding b = BuilderBinding.build(itemRow) ;
table.addBinding(b) ;
lastBinding = b ;
count++ ;
}
// Was it the unit table?
if ( table.size() == 1 )
{
// One row, no bindings.
if ( lastBinding.isEmpty() )
return TableFactory.createUnit() ;
}
return table ;
}
}