com.helger.commons.hierarchy.visit

Class DefaultHierarchyVisitorCallback<DATATYPE>

java.lang.Object

com.helger.commons.hierarchy.visit.DefaultHierarchyVisitorCallback<DATATYPE>

Type Parameters:

DATATYPE - The type of object in the hierarchy to be iterated

All Implemented Interfaces:

ICallback, IHierarchyVisitorCallback<DATATYPE>, Serializable

Direct Known Subclasses:

TreeVisitor.HierarchyVisitorCallbackWithConversion

public class DefaultHierarchyVisitorCallback<DATATYPE>
extends Object
implements IHierarchyVisitorCallback<DATATYPE>

The default implementation of the IHierarchyVisitorCallback interface doing nothing except counting levels.

Author:

Philip Helger

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
DefaultHierarchyVisitorCallback()
DefaultHierarchyVisitorCallback(int nInitialLevel)

Method Summary

Modifier and Type	Method and Description
void	begin() Called before the tree walking starts.
void	end() Called after the tree walking ended.
int	getLevel()
EHierarchyVisitorReturn	onItemAfterChildren(DATATYPE aItem) Called after eventual children of the current item were visited.
EHierarchyVisitorReturn	onItemBeforeChildren(DATATYPE aItem) Called before children of the current item are visited.
void	onLevelDown() Called before the tree walker descends into the next tree level.
void	onLevelUp() Called after the tree walker ascends into the previous tree level.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DefaultHierarchyVisitorCallback

public DefaultHierarchyVisitorCallback()

DefaultHierarchyVisitorCallback

public DefaultHierarchyVisitorCallback(int nInitialLevel)

Method Detail

begin

public void begin()

Description copied from interface: IHierarchyVisitorCallback

Called before the tree walking starts.

Specified by:

begin in interface IHierarchyVisitorCallback<DATATYPE>

getLevel

@Nonnegative
public int getLevel()

Specified by:

getLevel in interface IHierarchyVisitorCallback<DATATYPE>

Returns:

The level of the current node within the hierarchy. Always ≥ 0. The root item has level 0.

onLevelDown

@OverridingMethodsMustInvokeSuper
public void onLevelDown()

Description copied from interface: IHierarchyVisitorCallback

Called before the tree walker descends into the next tree level. After this call IHierarchyVisitorCallback.getLevel() should return a value increased by 1.

Specified by:

onLevelDown in interface IHierarchyVisitorCallback<DATATYPE>

onLevelUp

@OverridingMethodsMustInvokeSuper
public void onLevelUp()

Description copied from interface: IHierarchyVisitorCallback

Called after the tree walker ascends into the previous tree level. After this call IHierarchyVisitorCallback.getLevel() should return a value decreased by 1.

Specified by:

onLevelUp in interface IHierarchyVisitorCallback<DATATYPE>

onItemBeforeChildren

@Nonnull
public EHierarchyVisitorReturn onItemBeforeChildren(DATATYPE aItem)

Description copied from interface: IHierarchyVisitorCallback

Called before children of the current item are visited. This method is also to be called if no children are present at all.

Specified by:

onItemBeforeChildren in interface IHierarchyVisitorCallback<DATATYPE>

Parameters:

aItem - The current item. May be null.

Returns:

A non-null status code that determines how to continue iteration.

onItemAfterChildren

@Nonnull
public EHierarchyVisitorReturn onItemAfterChildren(DATATYPE aItem)

Description copied from interface: IHierarchyVisitorCallback

Called after eventual children of the current item were visited. This method is also to be called if no children are present at all. This method has always to be called if IHierarchyVisitorCallback.onItemBeforeChildren(Object) was called.

Specified by:

onItemAfterChildren in interface IHierarchyVisitorCallback<DATATYPE>

Parameters:

aItem - The current item. May be null.

Returns:

A non-null status code that determines how to continue iteration.

end

public void end()

Description copied from interface: IHierarchyVisitorCallback

Called after the tree walking ended.

Specified by:

end in interface IHierarchyVisitorCallback<DATATYPE>