/*
* JBoss, Home of Professional Open Source.
* See the COPYRIGHT.txt file distributed with this work for information
* regarding copyright ownership. Some portions may be licensed
* to Red Hat, Inc. under one or more contributor license agreements.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301 USA.
*/
package org.teiid.query.processor.relational;
import org.teiid.common.buffer.IndexedTupleSource;
import org.teiid.core.TeiidComponentException;
import org.teiid.core.TeiidProcessingException;
import org.teiid.query.sql.util.ValueIterator;
/**
* A ValueIterator implementation that iterates over the TupleSource
* results of a subquery ProcessorPlan. The plan will
* always have only one result column. Constant Object values will
* be returned, not Expressions.
*
* This implementation is resettable.
*/
class TupleSourceValueIterator implements ValueIterator{
private IndexedTupleSource tupleSourceIterator;
private int columnIndex;
TupleSourceValueIterator(IndexedTupleSource tupleSource, int columnIndex){
this.tupleSourceIterator = tupleSource;
this.columnIndex = columnIndex;
}
/**
* @see java.util.Iterator#hasNext()
*/
public boolean hasNext() throws TeiidComponentException{
try {
return tupleSourceIterator.hasNext();
} catch (TeiidProcessingException err) {
throw new TeiidComponentException(err, err.getMessage());
}
}
/**
* Returns constant Object values, not Expressions.
* @see java.util.Iterator#next()
*/
public Object next() throws TeiidComponentException{
try {
return tupleSourceIterator.nextTuple().get(columnIndex);
} catch (TeiidProcessingException err) {
throw new TeiidComponentException(err, err.getMessage());
}
}
/**
* Flags a reset as being needed
* @see org.teiid.query.sql.util.ValueIterator#reset()
*/
public void reset() {
this.tupleSourceIterator.reset();
}
}