Java tutorial
/* * 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.sql.planner; import com.facebook.presto.sql.planner.plan.IndexJoinNode; import com.facebook.presto.sql.planner.plan.JoinNode; import com.facebook.presto.sql.planner.plan.PlanNode; import com.facebook.presto.sql.planner.plan.PlanNodeId; import com.facebook.presto.sql.planner.plan.PlanVisitor; import com.facebook.presto.sql.planner.plan.SemiJoinNode; import com.facebook.presto.sql.planner.plan.TableScanNode; import com.google.common.collect.ImmutableList; import java.util.List; import java.util.function.Consumer; public class SchedulingOrderVisitor { public static List<PlanNodeId> scheduleOrder(PlanNode root) { ImmutableList.Builder<PlanNodeId> schedulingOrder = ImmutableList.builder(); root.accept(new Visitor(), schedulingOrder::add); return schedulingOrder.build(); } private SchedulingOrderVisitor() { } private static class Visitor extends PlanVisitor<Void, Consumer<PlanNodeId>> { @Override protected Void visitPlan(PlanNode node, Consumer<PlanNodeId> schedulingOrder) { for (PlanNode source : node.getSources()) { source.accept(this, schedulingOrder); } return null; } @Override public Void visitJoin(JoinNode node, Consumer<PlanNodeId> schedulingOrder) { node.getRight().accept(this, schedulingOrder); node.getLeft().accept(this, schedulingOrder); return null; } @Override public Void visitSemiJoin(SemiJoinNode node, Consumer<PlanNodeId> schedulingOrder) { node.getFilteringSource().accept(this, schedulingOrder); node.getSource().accept(this, schedulingOrder); return null; } @Override public Void visitIndexJoin(IndexJoinNode node, Consumer<PlanNodeId> schedulingOrder) { node.getIndexSource().accept(this, schedulingOrder); node.getProbeSource().accept(this, schedulingOrder); return null; } @Override public Void visitTableScan(TableScanNode node, Consumer<PlanNodeId> schedulingOrder) { schedulingOrder.accept(node.getId()); return null; } } }