JoinOperator.java

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// Copyright 2012 Cloudera Inc.
//
// 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.cloudera.impala.analysis;

import com.cloudera.impala.thrift.TJoinOp;

public enum JoinOperator {
  INNER_JOIN("INNER JOIN", TJoinOp.INNER_JOIN),
  LEFT_OUTER_JOIN("LEFT OUTER JOIN", TJoinOp.LEFT_OUTER_JOIN),
  LEFT_SEMI_JOIN("LEFT SEMI JOIN", TJoinOp.LEFT_SEMI_JOIN),
  LEFT_ANTI_JOIN("LEFT ANTI JOIN", TJoinOp.LEFT_ANTI_JOIN),
  RIGHT_OUTER_JOIN("RIGHT OUTER JOIN", TJoinOp.RIGHT_OUTER_JOIN),
  RIGHT_SEMI_JOIN("RIGHT SEMI JOIN", TJoinOp.RIGHT_SEMI_JOIN),
  RIGHT_ANTI_JOIN("RIGHT ANTI JOIN", TJoinOp.RIGHT_ANTI_JOIN),
  FULL_OUTER_JOIN("FULL OUTER JOIN", TJoinOp.FULL_OUTER_JOIN),
  CROSS_JOIN("CROSS JOIN", TJoinOp.CROSS_JOIN),
  // Variant of the LEFT ANTI JOIN that is used for the rewrite of
  // NOT IN subqueries. It can have a single equality join conjunct
  // that returns TRUE when the rhs is NULL.
  NULL_AWARE_LEFT_ANTI_JOIN("NULL AWARE LEFT ANTI JOIN",
      TJoinOp.NULL_AWARE_LEFT_ANTI_JOIN);

  private final String description_;
  private final TJoinOp thriftJoinOp_;

  private JoinOperator(String description, TJoinOp thriftJoinOp) {
    this.description_ = description;
    this.thriftJoinOp_ = thriftJoinOp;
  }

  @Override
  public String toString() {
    return description_;
  }

  public TJoinOp toThrift() {
    return thriftJoinOp_;
  }

  public boolean isInnerJoin() {
    return this == INNER_JOIN;
  }

  public boolean isOuterJoin() {
    return this == LEFT_OUTER_JOIN
        || this == RIGHT_OUTER_JOIN
        || this == FULL_OUTER_JOIN;
  }

  public boolean isSemiJoin() {
    return this == JoinOperator.LEFT_SEMI_JOIN || this == JoinOperator.LEFT_ANTI_JOIN ||
        this == JoinOperator.RIGHT_SEMI_JOIN || this == JoinOperator.RIGHT_ANTI_JOIN ||
        this == JoinOperator.NULL_AWARE_LEFT_ANTI_JOIN;
  }

  public boolean isLeftSemiJoin() {
    return this == JoinOperator.LEFT_SEMI_JOIN || this == JoinOperator.LEFT_ANTI_JOIN ||
        this == JoinOperator.NULL_AWARE_LEFT_ANTI_JOIN;
  }

  public boolean isRightSemiJoin() {
    return this == JoinOperator.RIGHT_SEMI_JOIN || this == JoinOperator.RIGHT_ANTI_JOIN;
  }

  public boolean isCrossJoin() {
    return this == JoinOperator.CROSS_JOIN;
  }

  public boolean isFullOuterJoin() {
    return this == JoinOperator.FULL_OUTER_JOIN;
  }

  public boolean isNullAwareLeftAntiJoin() {
    return this == JoinOperator.NULL_AWARE_LEFT_ANTI_JOIN;
  }

  public boolean isAntiJoin() {
    return this == JoinOperator.LEFT_ANTI_JOIN || this == JoinOperator.RIGHT_ANTI_JOIN ||
        this == JoinOperator.NULL_AWARE_LEFT_ANTI_JOIN;
  }

  public JoinOperator invert() {
    switch (this) {
      case LEFT_OUTER_JOIN: return RIGHT_OUTER_JOIN;
      case RIGHT_OUTER_JOIN: return LEFT_OUTER_JOIN;
      case LEFT_SEMI_JOIN: return RIGHT_SEMI_JOIN;
      case RIGHT_SEMI_JOIN: return LEFT_SEMI_JOIN;
      case LEFT_ANTI_JOIN: return RIGHT_ANTI_JOIN;
      case RIGHT_ANTI_JOIN: return LEFT_ANTI_JOIN;
      case NULL_AWARE_LEFT_ANTI_JOIN: throw new IllegalStateException("Not implemented");
      default: return this;
    }
  }
}