com.rabbitmq.jms.parse.Visitor Maven / Gradle / Ivy
/* Copyright (c) 2013 Pivotal Software, Inc. All rights reserved. */
package com.rabbitmq.jms.parse;
/**
* A visitor is guided by a {@link ParseTreeTraverser} to each {@link Node} of a tree.
*
* It is intended that {@link Visitor#visitBefore(Object, Object[])} and {@link Visitor#visitAfter(Object, Object[])} are called for each node in the tree.
* The order of traversal is both pre- and post-order: {@link #visitBefore(Object, Object[])} is called on a parent before the children are called,
* and {@link Visitor#visitAfter(Object, Object[])} is called after the children are called.
*
*
* The returned boolean is interpreted by the caller and its meaning is not part of the {@link Visitor} contract.
*
*/
public interface Visitor {
/**
* Visit a place in the tree: the Node for this place in the tree, and an array of {@link Node}s of the immediate children, are passed as parameters.
* @param parent - the node (value) of the parent at this point in the tree; can be updated.
* @param children - array of the nodes of the children of this parent (can be zero-length array; must not be null).
* @return true or false - interpreted by the caller (typically a tree traversal algorithm).
*/
boolean visitBefore(Node parent, Node[] children);
/**
* Visit a place in the tree: the Node for this place in the tree, and an array of {@link Node}s of the immediate children, are passed as parameters.
* @param parent - the node (value) of the parent at this point in the tree; can be updated.
* @param children - array of the nodes of the children of this parent (can be zero-length array; must not be null).
* @return true or false - interpreted by the caller (typically a tree traversal algorithm).
*/
boolean visitAfter (Node parent, Node[] children);
}