| /** |
| * 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.tajo.engine.function.window; |
| |
| import org.apache.tajo.catalog.Column; |
| import org.apache.tajo.catalog.proto.CatalogProtos; |
| import org.apache.tajo.common.TajoDataTypes; |
| import org.apache.tajo.datum.Datum; |
| import org.apache.tajo.datum.DatumFactory; |
| import org.apache.tajo.datum.Int8Datum; |
| import org.apache.tajo.plan.function.FunctionContext; |
| import org.apache.tajo.plan.function.WindowAggFunc; |
| import org.apache.tajo.engine.function.annotation.Description; |
| import org.apache.tajo.engine.function.annotation.ParamTypes; |
| import org.apache.tajo.storage.Tuple; |
| |
| @Description( |
| functionName = "rank", |
| description = " The number of rows for " |
| + "which the supplied expressions are unique and non-NULL.", |
| example = "> SELECT rank() OVER (ORDER BY x) FROM ...;", |
| returnType = TajoDataTypes.Type.INT8, |
| paramTypes = {@ParamTypes(paramTypes = {})} |
| ) |
| public final class Rank extends WindowAggFunc { |
| |
| public Rank() { |
| super(new Column[] { |
| new Column("expr", TajoDataTypes.Type.ANY) |
| }); |
| } |
| |
| public static boolean checkIfDistinctValue(RankContext context, Tuple params) { |
| for (int i = 0; i < context.latest.length; i++) { |
| if ((context.latest[i].isNotNull() || params.asDatum(i).isNotNull()) |
| && !context.latest[i].equalsTo(params.asDatum(i)).isTrue()) { |
| return true; |
| } |
| } |
| |
| return false; |
| } |
| |
| @Override |
| public void eval(FunctionContext context, Tuple params) { |
| RankContext ctx = (RankContext) context; |
| |
| if ((ctx.latest == null || checkIfDistinctValue(ctx, params))) { |
| ctx.rank = ctx.accumulatedCount; |
| ctx.latest = params.getValues().clone(); |
| } |
| ctx.accumulatedCount++; |
| } |
| |
| @Override |
| public Int8Datum terminate(FunctionContext ctx) { |
| return DatumFactory.createInt8(((RankContext) ctx).rank); |
| } |
| |
| @Override |
| public FunctionContext newContext() { |
| return new RankContext(); |
| } |
| |
| private static class RankContext implements FunctionContext { |
| long rank = 0; |
| long accumulatedCount = 1; |
| Datum [] latest = null; |
| } |
| |
| @Override |
| public CatalogProtos.FunctionType getFunctionType() { |
| return CatalogProtos.FunctionType.WINDOW; |
| } |
| } |