| /* |
| * 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.wayang.core.optimizer.cardinality; |
| |
| import org.apache.logging.log4j.LogManager; |
| import org.apache.wayang.core.optimizer.OptimizationContext; |
| import org.apache.wayang.core.plan.wayangplan.InputSlot; |
| |
| /** |
| * Forwards the {@link CardinalityEstimate} of any given {@link InputSlot} that is not {@code null}. Asserts that |
| * all other {@link CardinalityEstimate}s are indeed {@code null}. |
| */ |
| public class SwitchForwardCardinalityEstimator implements CardinalityEstimator { |
| |
| private final int[] switchInputIndices; |
| |
| public SwitchForwardCardinalityEstimator(int... switchInputIndices) { |
| assert switchInputIndices.length > 0; |
| this.switchInputIndices = switchInputIndices; |
| } |
| |
| @Override |
| public CardinalityEstimate estimate(OptimizationContext optimizationContext, CardinalityEstimate... inputEstimates) { |
| CardinalityEstimate forwardEstimate = null; |
| for (int switchInputIndex : this.switchInputIndices) { |
| final CardinalityEstimate inputEstimate = inputEstimates[switchInputIndex]; |
| if (inputEstimate != null) { |
| if (forwardEstimate != null) { |
| LogManager.getLogger(this.getClass()).error("Conflicting estimates {} and {}.", forwardEstimate, inputEstimate); |
| } |
| if (forwardEstimate == null || forwardEstimate.getCorrectnessProbability() > inputEstimate.getCorrectnessProbability()) { |
| forwardEstimate = inputEstimate; |
| } |
| } |
| } |
| assert forwardEstimate != null; |
| return forwardEstimate; |
| } |
| |
| } |