Package org.eclipse.jface.databinding.viewers

Class TreeStructureAdvisor<E>

java.lang.Object

org.eclipse.jface.databinding.viewers.TreeStructureAdvisor<E>

Type Parameters:

E - type of the elements in the tree

public abstract class TreeStructureAdvisor<E>
extends Object

Instances of this class can be used to improve accuracy and performance of an ObservableListTreeContentProvider or an ObservableSetTreeContentProvider. This class is intended to be subclassed by clients.

Since:

1.2

Constructor Summary

Constructors

Constructor	Description
TreeStructureAdvisor()

Method Summary

Modifier and Type	Method	Description
E	getParent(E element)	Returns the parent for the given element, or null indicating that the parent can't be computed.
Boolean	hasChildren(E element)	Returns whether the given element has children, or null if the actual children collection should be consulted.

Methods inherited from class java.lang.Object

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

Constructor Details

TreeStructureAdvisor

public TreeStructureAdvisor()

Method Details

getParent

public E getParent(E element)

Returns the parent for the given element, or null indicating that the parent can't be computed. In this case the tree-structured viewer can't expand a given node correctly if requested. The default implementation returns null; clients should override.

Parameters:

element - the element

Returns:

the parent element, or null if it has none or if the parent cannot be computed

hasChildren

public Boolean hasChildren(E element)

Returns whether the given element has children, or null if the actual children collection should be consulted. The default implementation returns null; clients should override.

Intended as an optimization for when the viewer does not need the actual children. Clients may be able to implement this more efficiently than getChildren.

Parameters:

element - the element

Returns:

Boolean.TRUE if the given element has children, Boolean.FALSE if the given element never has children, or null if the children collection should be consulted.