content: /*
   * 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.calcite.rel.core;
  
  import org.apache.calcite.plan.RelOptUtil;
  import org.apache.calcite.rel.RelNode;
  import org.apache.calcite.rex.RexBuilder;
  import org.apache.calcite.rex.RexNode;
  import org.apache.calcite.rex.RexUtil;
  import org.apache.calcite.runtime.FlatLists;
  import org.apache.calcite.util.ImmutableBitSet;
  import org.apache.calcite.util.ImmutableIntList;
  import org.apache.calcite.util.mapping.IntPair;
  
  import com.google.common.collect.ImmutableList;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import static java.util.Objects.requireNonNull;
  
  /** An analyzed join condition.
   *
   * <p>It is useful for the many algorithms that care whether a join has an
   * equi-join condition.
   *
   * <p>You can create one using {@link #createWithStrictEquality}, or call
   * {@link Join#analyzeCondition()}; many kinds of join cache their
   * join info, especially those that are equi-joins.
   *
   * @see Join#analyzeCondition() */
  public class JoinInfo {
    public final ImmutableIntList leftKeys;
    public final ImmutableIntList rightKeys;
    public final ImmutableList<RexNode> nonEquiConditions;
  
    /** Creates a JoinInfo. */
    protected JoinInfo(ImmutableIntList leftKeys, ImmutableIntList rightKeys,
        ImmutableList<RexNode> nonEquiConditions) {
      this.leftKeys = requireNonNull(leftKeys, "leftKeys");
      this.rightKeys = requireNonNull(rightKeys, "rightKeys");
      this.nonEquiConditions =
          requireNonNull(nonEquiConditions, "nonEquiConditions");
      assert leftKeys.size() == rightKeys.size();
    }
  
    /** Creates a {@code JoinInfo} by analyzing a condition. */
    public static JoinInfo of(RelNode left, RelNode right, RexNode condition) {
      final List<Integer> leftKeys = new ArrayList<>();
      final List<Integer> rightKeys = new ArrayList<>();
      final List<Boolean> filterNulls = new ArrayList<>();
      final List<RexNode> nonEquiList = new ArrayList<>();
      RelOptUtil.splitJoinCondition(left, right, condition, leftKeys, rightKeys,
          filterNulls, nonEquiList);
      return new JoinInfo(ImmutableIntList.copyOf(leftKeys),
          ImmutableIntList.copyOf(rightKeys), ImmutableList.copyOf(nonEquiList));
    }
  
    /** Creates a {@code JoinInfo} by analyzing a condition.
     * A JoinInfo created using this method only considers
     * EQUALS operations equi-conditions; in contrast
     * IS_NOT_DISTINCT_FROM operations are NOT considered equalities;
     * they are inserted in the nonEquiList. */
    public static JoinInfo createWithStrictEquality(RelNode left,
        RelNode right, RexNode condition) {
      final List<Integer> leftKeys = new ArrayList<>();
      final List<Integer> rightKeys = new ArrayList<>();
      final List<RexNode> nonEquiList = new ArrayList<>();
      RelOptUtil.splitJoinCondition(left, right, condition, leftKeys, rightKeys,
          null, nonEquiList);
      return new JoinInfo(ImmutableIntList.copyOf(leftKeys),
          ImmutableIntList.copyOf(rightKeys), ImmutableList.copyOf(nonEquiList));
    }
  
    /** Creates an equi-join. */
    public static JoinInfo of(ImmutableIntList leftKeys,
        ImmutableIntList rightKeys) {
      return new JoinInfo(leftKeys, rightKeys, ImmutableList.of());
    }
  
    /** Returns whether this is an equi-join. */
    public boolean isEqui() {
      return nonEquiConditions.isEmpty();
    }
  
    /** Returns a list of (left, right) key ordinals. */
    public List<IntPair> pairs() {
      return IntPair.zip(leftKeys, rightKeys);
    }
  
    public ImmutableBitSet leftSet() {
      return ImmutableBitSet.of(leftKeys);
    }
  
    public ImmutableBitSet rightSet() {
      return ImmutableBitSet.of(rightKeys);
    }
  
    @Deprecated // to be removed before 2.0
    public RexNode getRemaining(RexBuilder rexBuilder) {
      return RexUtil.composeConjunction(rexBuilder, nonEquiConditions);
    }
  
    public RexNode getEquiCondition(RelNode left, RelNode right,
        RexBuilder rexBuilder) {
      return RelOptUtil.createEquiJoinCondition(left, leftKeys, right, rightKeys,
          rexBuilder);
    }
  
    public List<ImmutableIntList> keys() {
      return FlatLists.of(leftKeys, rightKeys);
    }
  
  }
  