content: /*
   * Copyright 2021-2022 Alibaba Group Holding Ltd.
   *
   *    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.aliyun.fastmodel.core.tree.util;
  
  import java.util.List;
  
  import com.aliyun.fastmodel.core.tree.expr.BaseExpression;
  import com.aliyun.fastmodel.core.tree.expr.LogicalBinaryExpression;
  import com.aliyun.fastmodel.core.tree.expr.enums.LogicalOperator;
  import com.google.common.collect.ImmutableList;
  
  /**
   * ExpressionUtils
   *
   * @author panguanjing
   * @date 2021/3/18
   */
  public final class ExpressionUtil {
  
      private ExpressionUtil() {
  
      }
  
      public static List<BaseExpression> extractPredicates(LogicalBinaryExpression expression) {
          return extractPredicates(expression.getOperator(), expression);
      }
  
      public static List<BaseExpression> extractPredicates(LogicalOperator operator, BaseExpression expression) {
          ImmutableList.Builder<BaseExpression> resultBuilder = ImmutableList.builder();
          extractPredicates(operator, expression, resultBuilder);
          return resultBuilder.build();
      }
  
      private static void extractPredicates(LogicalOperator operator, BaseExpression expression,
                                            ImmutableList.Builder<BaseExpression> resultBuilder) {
          if (expression instanceof LogicalBinaryExpression
              && ((LogicalBinaryExpression)expression).getOperator() == operator) {
              LogicalBinaryExpression logicalBinaryExpression = (LogicalBinaryExpression)expression;
              extractPredicates(operator, logicalBinaryExpression.getLeft(), resultBuilder);
              extractPredicates(operator, logicalBinaryExpression.getRight(), resultBuilder);
          } else {
              resultBuilder.add(expression);
          }
      }
  }
  