/**
* 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.atlas.gremlin.optimizer;
import org.apache.atlas.groovy.AbstractFunctionExpression;
import org.apache.atlas.groovy.GroovyExpression;
/**
* Call back interface for visiting the call hierarchy of a function call.
*/
public interface CallHierarchyVisitor {
/**
* Visits a function expression before the visit to its caller.
*
* @param expr
*
* @return false to terminate the recursion
*/
boolean preVisitFunctionCaller(AbstractFunctionExpression expr);
/**
* Called when a caller that is not an instance of
* AbstractFunctionExpression is found. This indicates that the deepest
* point in the call hierarchy has been reached.
*
*
*/
void visitNonFunctionCaller(GroovyExpression expr);
/**
* Called when a null caller is found (this happens for static/user-defined
* functions). This indicates that the deepest point in the call hierarchy
* has been reached.
*
*/
void visitNullCaller();
/**
* Visits a function expression after the visit to its caller.
*
* @param expr
*
* @return false to terminate the recursion
*/
boolean postVisitFunctionCaller(AbstractFunctionExpression functionCall);
}