/*
 * 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 table;

import java.util.Iterator ;
import java.util.List ;

import com.hp.hpl.jena.sparql.core.Var ;
import com.hp.hpl.jena.sparql.engine.binding.Binding ;

/** A SPARQL table : each row is a set of variable-value pairs.
 *  A table is ragged - not every row has a binding for every column. 
 */
public interface Table
{
    /** The columns on the table. 
     *  Any given row will only bindings for a variable in the columns list but
     *  a particular row may not have a binding for a particular variable. 
     */
    
    public List<Var> vars() ;
    
    /**
     * The rows of the table as an iterator.
     */
    public Iterator<Binding> rows() ;
}