/* * 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 com.facebook.presto.operator.window; import com.facebook.presto.spi.block.BlockBuilder; import com.facebook.presto.spi.function.RankingWindowFunction; import com.facebook.presto.spi.function.WindowFunctionSignature; import static com.facebook.presto.spi.type.DoubleType.DOUBLE; @WindowFunctionSignature(name = "cume_dist", returnType = "double") public class CumulativeDistributionFunction extends RankingWindowFunction { private long totalCount; private long count; @Override public void reset() { totalCount = windowIndex.size(); count = 0; } @Override public void processRow(BlockBuilder output, boolean newPeerGroup, int peerGroupCount, int currentPosition) { if (newPeerGroup) { count += peerGroupCount; } DOUBLE.writeDouble(output, ((double) count) / totalCount); } }