| /* |
| * 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.ArrayList; |
| import java.util.List; |
| import java.util.Locale; |
| |
| import org.apache.commons.math3.stat.descriptive.DescriptiveStatistics; |
| import org.apache.commons.math3.stat.descriptive.rank.Percentile; |
| import org.apache.solr.client.solrj.io.stream.expr.StreamExpression; |
| import org.apache.solr.client.solrj.io.stream.expr.StreamFactory; |
| |
| public class MovingMedianEvaluator extends RecursiveNumericEvaluator implements TwoValueWorker { |
| protected static final long serialVersionUID = 1L; |
| |
| public MovingMedianEvaluator(StreamExpression expression, StreamFactory factory) throws IOException{ |
| super(expression, factory); |
| } |
| |
| @Override |
| public Object doWork(Object first, Object second) throws IOException{ |
| if(null == first){ |
| throw new IOException(String.format(Locale.ROOT,"Invalid expression %s - null found for the first value",toExpression(constructingFactory))); |
| } |
| if(null == second){ |
| throw new IOException(String.format(Locale.ROOT,"Invalid expression %s - null found for the second value",toExpression(constructingFactory))); |
| } |
| if(!(first instanceof List<?>)){ |
| throw new IOException(String.format(Locale.ROOT,"Invalid expression %s - found type %s for the first value, expecting a List",toExpression(constructingFactory), first.getClass().getSimpleName())); |
| } |
| if(!(second instanceof Number)){ |
| throw new IOException(String.format(Locale.ROOT,"Invalid expression %s - found type %s for the second value, expecting a Number",toExpression(constructingFactory), first.getClass().getSimpleName())); |
| } |
| |
| List<?> values = (List<?>)first; |
| int window = ((Number)second).intValue(); |
| |
| List<Number> moving = new ArrayList<>(); |
| DescriptiveStatistics slider = new DescriptiveStatistics(window); |
| Percentile percentile = new Percentile(); |
| for(Object value : values){ |
| slider.addValue(((Number)value).doubleValue()); |
| if(slider.getN() >= window){ |
| double median = percentile.evaluate(slider.getValues(), 50); |
| moving.add(median); |
| } |
| } |
| |
| return moving; |
| } |
| |
| } |