com.phloc.commons.hierarchy.IBaseHierarchyWalker Maven / Gradle / Ivy
/**
* Copyright (C) 2006-2015 phloc systems
* http://www.phloc.com
* office[at]phloc[dot]com
*
* 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.phloc.commons.hierarchy;
import javax.annotation.Nonnegative;
/**
* Base interface for iterating a hierarchy.
*
* @author Philip Helger
*/
public interface IBaseHierarchyWalker
{
/**
* Called before the tree walking starts.
*/
void begin ();
/**
* Called before the tree walker descends into the next tree level.
*/
void onLevelDown ();
/**
* @return The level of the current node within the tree. The root item has
* level 0.
*/
@Nonnegative
int getLevel ();
/**
* Called after the tree walker ascends into the previous tree level.
*/
void onLevelUp ();
/**
* Called after the tree walking ended.
*/
void end ();
}