/*
* 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.function.aggregate;
import java.util.List;
import org.teiid.api.exception.query.ExpressionEvaluationException;
import org.teiid.api.exception.query.FunctionExecutionException;
import org.teiid.core.TeiidComponentException;
import org.teiid.core.TeiidProcessingException;
import org.teiid.query.QueryPlugin;
import org.teiid.query.sql.symbol.AggregateSymbol.Type;
import org.teiid.query.util.CommandContext;
/**
* computes rank/dense_rank
*/
public class RankingFunction extends AggregateFunction {
private int count = 0;
private int lastCount = 0;
private Type type;
public RankingFunction(Type function) {
this.type = function;
}
@Override
public void reset() {
count = 0;
lastCount = 0;
}
@Override
public void addInputDirect(List<?> tuple, CommandContext commandContext)
throws FunctionExecutionException, ExpressionEvaluationException,
TeiidComponentException {
if (type == Type.RANK) {
if (count == Integer.MAX_VALUE) {
throw new ExpressionEvaluationException(QueryPlugin.Event.TEIID31174, QueryPlugin.Util.gs(QueryPlugin.Event.TEIID31174));
}
count++;
}
}
@Override
public Object getResult(CommandContext commandContext) throws FunctionExecutionException,
ExpressionEvaluationException, TeiidComponentException {
if (type == Type.DENSE_RANK) {
if (count == Integer.MAX_VALUE) {
throw new ExpressionEvaluationException(QueryPlugin.Event.TEIID31174, QueryPlugin.Util.gs(QueryPlugin.Event.TEIID31174));
}
count++;
return count;
}
int result = ++lastCount;
lastCount = count;
return result;
}
}