/*
* $Header$
* $Revision: 982 $
* $Date: 2006-12-08 18:42:51 +1000 (Fri, 08 Dec 2006) $
*
* ====================================================================
*
* The Apache Software License, Version 1.1
*
* Copyright (c) 2003-2009 The JRDF Project. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowlegement:
* "This product includes software developed by the
* the JRDF Project (http://jrdf.sf.net/)."
* Alternately, this acknowlegement may appear in the software itself,
* if and wherever such third-party acknowlegements normally appear.
*
* 4. The names "The JRDF Project" and "JRDF" must not be used to endorse
* or promote products derived from this software without prior written
* permission. For written permission, please contact
* newmana@users.sourceforge.net.
*
* 5. Products derived from this software may not be called "JRDF"
* nor may "JRDF" appear in their names without prior written
* permission of the JRDF Project.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the JRDF Project. For more
* information on JRDF, please see <http://jrdf.sourceforge.net/>.
*
*/
package org.jrdf.query.answer;
import org.jrdf.graph.Node;
import org.jrdf.query.relation.Attribute;
import org.jrdf.query.relation.Tuple;
import org.jrdf.query.relation.constants.NullaryNode;
import org.jrdf.util.ClosableIterator;
import java.util.Map;
import java.util.Set;
public class AnswerIterator implements ClosableIterator<TypeValue[]> {
private Set<Attribute> heading;
private ClosableIterator<Tuple> tupleIterator;
private NodeToTypeValue nodeToTypeValue = new NodeToTypeValueImpl();
public AnswerIterator(Set<Attribute> newHeading, ClosableIterator<Tuple> newTupleIterator) {
this.heading = newHeading;
this.tupleIterator = newTupleIterator;
}
public boolean hasNext() {
return tupleIterator.hasNext();
}
public TypeValue[] next() {
Tuple tuple = tupleIterator.next();
return getDataWithValues(tuple.getAttributeValues());
}
private TypeValue[] getDataWithValues(Map<Attribute, Node> avps) {
TypeValue[] results = new TypeValue[heading.size()];
int index = 0;
for (Attribute headingAttribute : heading) {
org.jrdf.graph.Node value;
try {
value = avps.get(headingAttribute);
} catch (Exception e) {
value = NullaryNode.NULLARY_NODE;
}
results[index] = nodeToTypeValue.convert(value);
index++;
}
return results;
}
public void remove() {
throw new UnsupportedOperationException("Cannot remove values from an answer iterator");
}
public boolean close() {
return tupleIterator.close();
}
}