| /* |
| * 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 org.apache.rya.api.model.VisibilityBindingSet; |
| import org.openrdf.model.Value; |
| import org.openrdf.query.algebra.evaluation.util.ValueComparator; |
| import org.openrdf.query.impl.MapBindingSet; |
| |
| import edu.umd.cs.findbugs.annotations.DefaultAnnotation; |
| import edu.umd.cs.findbugs.annotations.NonNull; |
| |
| /** |
| * Update the {@link AggregationState}'s max if the child binding Set contains the binding name that is being |
| * maxed by the {@link AggregationElement}. |
| */ |
| @DefaultAnnotation(NonNull.class) |
| public final class MaxFunction implements AggregationFunction { |
| |
| private final ValueComparator compare = new ValueComparator(); |
| |
| @Override |
| public void update(final AggregationElement aggregation, final AggregationState state, final VisibilityBindingSet childBindingSet) { |
| checkArgument(aggregation.getAggregationType() == AggregationType.MAX, "The MaxFunction only accepts MAX AggregationElements."); |
| requireNonNull(state); |
| requireNonNull(childBindingSet); |
| |
| // Only update the max if the child contains the binding that we are finding the max value for. |
| 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); |
| |
| Value max; |
| if(newBinding) { |
| max = childBindingSet.getValue(aggregatedName); |
| } else { |
| final Value oldMax = result.getValue(resultName); |
| final Value childMax = childBindingSet.getValue(aggregatedName); |
| max = compare.compare(childMax, oldMax) > 0 ? childMax : oldMax; |
| } |
| |
| result.addBinding(resultName, max); |
| } |
| } |
| } |