| /* |
| * 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.analytics.function.reduction; |
| |
| import java.io.Serializable; |
| import java.util.function.UnaryOperator; |
| |
| import org.apache.solr.analytics.ExpressionFactory.CreatorFunction; |
| import org.apache.solr.analytics.function.ReductionFunction; |
| import org.apache.solr.analytics.function.reduction.data.CountCollector; |
| import org.apache.solr.analytics.function.reduction.data.CountCollector.ExpressionCountCollector; |
| import org.apache.solr.analytics.function.reduction.data.ReductionData; |
| import org.apache.solr.analytics.function.reduction.data.ReductionDataCollector; |
| import org.apache.solr.analytics.function.reduction.data.SumCollector; |
| import org.apache.solr.analytics.value.AnalyticsValueStream; |
| import org.apache.solr.analytics.value.DoubleValueStream; |
| import org.apache.solr.analytics.value.DoubleValue.AbstractDoubleValue; |
| import org.apache.solr.common.SolrException; |
| import org.apache.solr.common.SolrException.ErrorCode; |
| |
| /** |
| * A reduction function which returns the mean of the values of the given expression. |
| */ |
| public class MeanFunction extends AbstractDoubleValue implements ReductionFunction { |
| private SumCollector sumCollector; |
| private CountCollector countCollector; |
| public static final String name = "mean"; |
| private final String exprStr; |
| public static final CreatorFunction creatorFunction = (params -> { |
| if (params.length != 1) { |
| throw new SolrException(ErrorCode.BAD_REQUEST,"The "+name+" function requires 1 paramater, " + params.length + " found."); |
| } |
| DoubleValueStream casted; |
| try { |
| casted = (DoubleValueStream) params[0]; |
| } |
| catch (ClassCastException e) { |
| throw new SolrException(ErrorCode.BAD_REQUEST,"The "+name+" function requires numeric parameter. " + |
| "Incorrect parameter: "+params[0].getExpressionStr()); |
| } |
| return new MeanFunction(casted); |
| }); |
| |
| public MeanFunction(DoubleValueStream param) { |
| this.sumCollector = new SumCollector(param); |
| this.countCollector = new ExpressionCountCollector(param); |
| this.exprStr = AnalyticsValueStream.createExpressionString(name,param); |
| } |
| |
| @Override |
| public double getDouble() { |
| return (countCollector.count() > 0)? sumCollector.sum() / countCollector.count() : 0; |
| } |
| @Override |
| public boolean exists() { |
| return sumCollector.exists() && countCollector.count() > 0; |
| } |
| |
| @Override |
| public void synchronizeDataCollectors(UnaryOperator<ReductionDataCollector<?>> sync) { |
| sumCollector = (SumCollector) sync.apply(sumCollector); |
| countCollector = (CountCollector) sync.apply(countCollector); |
| } |
| |
| @Override |
| public String getExpressionStr() { |
| return exprStr; |
| } |
| @Override |
| public String getName() { |
| return name; |
| } |
| |
| @Override |
| public ExpressionType getExpressionType() { |
| return ExpressionType.REDUCTION; |
| } |
| |
| protected static class SumData extends ReductionData implements Serializable { |
| private static final long serialVersionUID = 5920718235872898338L; |
| double sum; |
| } |
| } |