| /* |
| * 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 org.apache.solr.client.solrj.io.eval; |
| |
| import java.io.IOException; |
| import java.util.Locale; |
| |
| import org.apache.commons.math3.util.*; |
| import org.apache.solr.client.solrj.io.stream.expr.StreamExpression; |
| import org.apache.solr.client.solrj.io.stream.expr.StreamFactory; |
| |
| public class BinomialCoefficientEvaluator extends RecursiveNumericEvaluator implements ManyValueWorker { |
| protected static final long serialVersionUID = 1L; |
| |
| public BinomialCoefficientEvaluator(StreamExpression expression, StreamFactory factory) throws IOException { |
| super(expression, factory); |
| if(2 != containedEvaluators.size()){ |
| throw new IOException(String.format(Locale.ROOT,"Invalid expression %s - expecting two values but found %d",expression, containedEvaluators.size())); |
| } |
| } |
| |
| @Override |
| public Object doWork(Object... values) throws IOException { |
| if(2 != values.length){ |
| throw new IOException(String.format(Locale.ROOT,"%s(...) only works with 2 values but %d were provided", constructingFactory.getFunctionName(getClass()), values.length)); |
| } |
| int set = ((Number)values[0]).intValue(); |
| int subset = ((Number)values[1]).intValue(); |
| return CombinatoricsUtils.binomialCoefficient(set, subset); |
| } |
| } |