/*
 * 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.sql.planner.iterative;

import com.facebook.presto.sql.planner.plan.PlanNode;

public interface Lookup
{
    /**
     * Resolves a node by materializing GroupReference nodes
     * representing symbolic references to other nodes.
     *
     * If the node is not a GroupReference, it returns the
     * argument as is.
     */
    PlanNode resolve(PlanNode node);
}

@@ -662,16 +662,100 @@
 nNode;%0A%0A
+import java.util.Optional;%0A%0Aimport static com.facebook.presto.util.Optionals.cast;%0A%0A
 public i
@@ -1030,11 +1030,149 @@
 e node);
+%0A%0A    default %3CT extends PlanNode%3E Optional%3CT%3E resolve(PlanNode node, Class%3CT%3E target) %7B%0A        return cast(resolve(node), target);%0A    %7D
 %0A%7D%0A

Add Lookup.resolve(PlanNode, Class<T>) : Optional<T> method