| /* |
| * 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.rya.api.function.aggregation; |
| |
| import static com.google.common.base.Preconditions.checkArgument; |
| import static java.util.Objects.requireNonNull; |
| |
| import java.math.BigDecimal; |
| import java.math.BigInteger; |
| import java.util.Map; |
| |
| import org.apache.rya.api.model.VisibilityBindingSet; |
| import org.eclipse.rdf4j.model.Literal; |
| import org.eclipse.rdf4j.model.Value; |
| import org.eclipse.rdf4j.model.ValueFactory; |
| import org.eclipse.rdf4j.model.datatypes.XMLDatatypeUtil; |
| import org.eclipse.rdf4j.model.impl.SimpleValueFactory; |
| import org.eclipse.rdf4j.query.algebra.MathExpr.MathOp; |
| import org.eclipse.rdf4j.query.algebra.evaluation.ValueExprEvaluationException; |
| import org.eclipse.rdf4j.query.algebra.evaluation.util.MathUtil; |
| import org.eclipse.rdf4j.query.impl.MapBindingSet; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import edu.umd.cs.findbugs.annotations.DefaultAnnotation; |
| import edu.umd.cs.findbugs.annotations.NonNull; |
| |
| /** |
| * Update the {@link AggregationState}'s average if the child Binding Set contains the binding name |
| * that is being averaged by the {@link AggregationElement}. |
| */ |
| @DefaultAnnotation(NonNull.class) |
| public final class AverageFunction implements AggregationFunction { |
| private static final Logger log = LoggerFactory.getLogger(AverageFunction.class); |
| private static final ValueFactory VF = SimpleValueFactory.getInstance(); |
| |
| @Override |
| public void update(final AggregationElement aggregation, final AggregationState state, final VisibilityBindingSet childBindingSet) { |
| checkArgument(aggregation.getAggregationType() == AggregationType.AVERAGE, "The AverageFunction only accepts AVERAGE AggregationElements."); |
| requireNonNull(state); |
| requireNonNull(childBindingSet); |
| |
| // Only update the average if the child contains the binding that we are averaging. |
| final String aggregatedName = aggregation.getAggregatedBindingName(); |
| if(childBindingSet.hasBinding(aggregatedName)) { |
| final MapBindingSet result = state.getBindingSet(); |
| final String resultName = aggregation.getResultBindingName(); |
| final boolean newBinding = !result.hasBinding(resultName); |
| |
| // Get the state of the average. |
| final Map<String, AverageState> averageStates = state.getAverageStates(); |
| AverageState averageState = newBinding ? new AverageState() : averageStates.get(resultName); |
| |
| // Update the state of the average. |
| final Value childValue = childBindingSet.getValue(aggregatedName); |
| if(childValue instanceof Literal) { |
| final Literal childLiteral = (Literal) childValue; |
| if (childLiteral.getDatatype() != null && XMLDatatypeUtil.isNumericDatatype(childLiteral.getDatatype())) { |
| try { |
| // Update the sum. |
| final Literal oldSum = VF.createLiteral(averageState.getSum()); |
| final BigDecimal sum = MathUtil.compute(oldSum, childLiteral, MathOp.PLUS).decimalValue(); |
| |
| // Update the count. |
| final BigInteger count = averageState.getCount().add( BigInteger.ONE ); |
| |
| // Update the BindingSet to include the new average. |
| final Literal sumLiteral = VF.createLiteral(sum); |
| final Literal countLiteral = VF.createLiteral(count); |
| final Literal average = MathUtil.compute(sumLiteral, countLiteral, MathOp.DIVIDE); |
| result.addBinding(resultName, average); |
| |
| // Update the average state that is stored. |
| averageState = new AverageState(sum, count); |
| averageStates.put(resultName, averageState); |
| } catch (final ValueExprEvaluationException e) { |
| log.error("A problem was encountered while updating an Average Aggregation. This binding set will be ignored: " + childBindingSet); |
| return; |
| } |
| } |
| } |
| } |
| } |
| } |