content: /*
   * Copyright 2020 Alibaba Group Holding Limited.
   *
   * 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.alibaba.graphscope.gremlin.antlr4x.visitor;
  
  import org.apache.calcite.rel.RelNode;
  import org.apache.calcite.rel.core.Project;
  
  import java.util.function.Predicate;
  
  public class SubQueryChecker implements Predicate<RelNode> {
      private final RelNode commonRel;
  
      public SubQueryChecker(RelNode commonRel) {
          this.commonRel = commonRel;
      }
  
      @Override
      public boolean test(RelNode rel) {
          return !(!rel.getInputs().isEmpty()
                  && rel.getInput(0).equals(commonRel)
                  && rel instanceof Project);
      }
  }
  