/** * 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.plan.rewrite; import org.apache.tajo.algebra.Expr; import org.apache.tajo.catalog.CatalogService; import org.apache.tajo.exception.TajoException; import org.apache.tajo.plan.ExprAnnotator; import org.apache.tajo.plan.LogicalPlanner.PlanContext; import org.apache.tajo.plan.logical.LogicalNode; public abstract class LogicalPlanPreprocessPhase { protected final CatalogService catalog; protected final ExprAnnotator annotator; public LogicalPlanPreprocessPhase(CatalogService catalog, ExprAnnotator annotator) { this.catalog = catalog; this.annotator = annotator; } /** * It returns the pre-process phase name. It will be used for debugging and * building a optimization history. * * @return The pre-process phase name */ public abstract String getName(); /** * This method checks if this pre-process phase can be applied to the given expression tree. * * @param context * @param expr * @return */ public abstract boolean isEligible(PlanContext context, Expr expr) throws TajoException; /** * Do a pre-process phase for an expression tree and returns it. * It must be guaranteed that the input expression tree is not modified even after rewrite. * In other words, the rewrite has to modify a copy of the expression tree. * * @param context * @param expr * @return The rewritten logical plan. */ public abstract LogicalNode process(PlanContext context, Expr expr) throws TajoException; }