/*
 * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
 * or more contributor license agreements. Licensed under the "Elastic License
 * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
 * Public License v 1"; you may not use this file except in compliance with, at
 * your election, the "Elastic License 2.0", the "GNU Affero General Public
 * License v3.0 only", or the "Server Side Public License, v 1".
 */

package org.elasticsearch.painless.node;

import org.elasticsearch.painless.Location;
import org.elasticsearch.painless.phase.UserTreeVisitor;

import static java.util.Objects.requireNonNull;

/**
 * The Elvis operator ({@code ?:}), a null coalescing operator. Binary operator that evaluates the first expression and return it if it is
 * non null. If the first expression is null then it evaluates the second expression and returns it.
 */
public class EElvis extends AExpression {

    private final AExpression leftNode;
    private final AExpression rightNode;

    public EElvis(int identifier, Location location, AExpression leftNode, AExpression rightNode) {
        super(identifier, location);

        this.leftNode = requireNonNull(leftNode);
        this.rightNode = requireNonNull(rightNode);
    }

    public AExpression getLeftNode() {
        return leftNode;
    }

    public AExpression getRightNode() {
        return rightNode;
    }

    @Override
    public <Scope> void visit(UserTreeVisitor<Scope> userTreeVisitor, Scope scope) {
        userTreeVisitor.visitElvis(this, scope);
    }

    @Override
    public <Scope> void visitChildren(UserTreeVisitor<Scope> userTreeVisitor, Scope scope) {
        leftNode.visit(userTreeVisitor, scope);
        rightNode.visit(userTreeVisitor, scope);
    }
}