EquiJoinClause.java

/*
 * 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.spi.plan;

import com.facebook.presto.spi.relation.VariableReferenceExpression;
import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonProperty;

import java.util.Objects;

import static java.lang.String.format;
import static java.util.Objects.requireNonNull;

public class EquiJoinClause
{
    private final VariableReferenceExpression left;
    private final VariableReferenceExpression right;

    @JsonCreator
    public EquiJoinClause(@JsonProperty("left") VariableReferenceExpression left, @JsonProperty("right") VariableReferenceExpression right)
    {
        this.left = requireNonNull(left, "left is null");
        this.right = requireNonNull(right, "right is null");
    }

    @JsonProperty
    public VariableReferenceExpression getLeft()
    {
        return left;
    }

    @JsonProperty
    public VariableReferenceExpression getRight()
    {
        return right;
    }

    public EquiJoinClause flip()
    {
        return new EquiJoinClause(right, left);
    }

    @Override
    public boolean equals(Object obj)
    {
        if (this == obj) {
            return true;
        }

        if (obj == null || !this.getClass().equals(obj.getClass())) {
            return false;
        }

        EquiJoinClause other = (EquiJoinClause) obj;

        return Objects.equals(this.left, other.left) &&
                Objects.equals(this.right, other.right);
    }

    @Override
    public int hashCode()
    {
        return Objects.hash(left, right);
    }

    @Override
    public String toString()
    {
        return format("%s = %s", left, right);
    }
}