/*
* 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.flink.util;
import org.apache.flink.annotation.Internal;
/**
* A visitor encapsulates functionality that is applied to each node in the process of a traversal of a tree or DAD.
*/
@Internal
public interface Visitor<T extends Visitable<T>> {
/**
*
* @param visitable
*
* @return True, if the traversal should continue, false otherwise.
*/
boolean preVisit(T visitable);
/**
* @param visitable
*/
void postVisit(T visitable);
}