/*********************************************************************************************************************** * Copyright (C) 2010-2013 by the Stratosphere project (http://stratosphere.eu) * * Licensed 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 eu.stratosphere.compiler.dag; import java.util.Collections; import java.util.List; import eu.stratosphere.api.common.operators.base.FlatMapOperatorBase; import eu.stratosphere.compiler.DataStatistics; import eu.stratosphere.compiler.operators.FlatMapDescriptor; import eu.stratosphere.compiler.operators.OperatorDescriptorSingle; /** * The optimizer's internal representation of a <i>FlatMap</i> operator node. */ public class FlatMapNode extends SingleInputNode { public FlatMapNode(FlatMapOperatorBase<?, ?, ?> operator) { super(operator); } @Override public FlatMapOperatorBase<?, ?, ?> getPactContract() { return (FlatMapOperatorBase<?, ?, ?>) super.getPactContract(); } @Override public String getName() { return "FlatMap"; } @Override protected List<OperatorDescriptorSingle> getPossibleProperties() { return Collections.<OperatorDescriptorSingle>singletonList(new FlatMapDescriptor()); } /** * Computes the estimates for the FlatMap operator. Since it un-nests, we assume a cardinality * increase. To give the system a hint at data increase, we take a default magic number of a 5 times increase. */ @Override protected void computeOperatorSpecificDefaultEstimates(DataStatistics statistics) { this.estimatedNumRecords = getPredecessorNode().getEstimatedNumRecords() * 5; } }