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org.eclipse.jface.viewers
Interface ILazyTreePathContentProvider
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All Superinterfaces:
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IContentProvider
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public interface ILazyTreePathContentProvider
- extends
IContentProvider
The ILazyTreePathContentProvider is a tree path-based content provider for
tree viewers created using the SWT.VIRTUAL flag that only wish to return
their contents as they are queried.
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Since:
- 3.3
updateElement
void updateElement(
TreePath parentPath,
int index)
- Called when a previously-blank item becomes visible in the TreeViewer. If
the content provider knows the child element for the given parent at this
index, it should respond by calling
TreeViewer.replace(Object, int, Object) . The content provider
should also update the child count for any replaced element by calling
TreeViewer.setChildCount(Object, int) . If the given current child
count is already correct, setChildCount does not have to be called since
a call to replace will not change the child count.
NOTE #updateElement(int index) can be used to determine
selection values. If TableViewer#replace(Object, int) is not called
before returning from this method, selections may have missing or stale
elements. In this situation it is suggested that the selection is asked
for again after replace() has been called.
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Parameters:
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parentPath - The tree path of parent of the element, or if the
element to update is a root element, an empty tree path -
index - The index of the element to update in the tree
updateChildCount
void updateChildCount(
TreePath treePath,
int currentChildCount)
- Called when the TreeViewer needs an up-to-date child count for the given
tree path, for example from
StructuredViewer.refresh() and
StructuredViewer.setInput(Object) . If the content provider knows the
element at the given tree path, it should respond by calling
TreeViewer.setChildCount(Object, int) . If the given current
child count is already correct, no action has to be taken by this content
provider.
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Parameters:
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treePath - The tree path for which an up-to-date child count is needed, or
if the number of root elements is requested, the empty tree path -
currentChildCount - The current child count for the element that needs updating
updateHasChildren
void updateHasChildren(
TreePath path)
- Called when the TreeViewer needs up-to-date information whether the node
at the given tree path can be expanded. If the content provider knows the
element at the given tree path, it should respond by calling
TreeViewer.setHasChildren(Object, boolean) . The content provider
may also choose to call
TreeViewer.setChildCount(Object, int)
instead if it knows the number of children.
Intended as an optimization for when the viewer does not need the actual
children. Clients may be able to implement this more efficiently than
updateChildCount .
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Parameters:
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path - The tree path for which up-to-date information about children
is needed
getParents
TreePath[] getParents(
Object element)
- Return the possible parent paths for the given element. An empty array
can be returned if the paths cannot be computed. In this case the
tree-structured viewer can't expand a given node correctly if requested.
If the element is a potential child of the input of the viewer, an empty
tree path should be an entry in the returned array.
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Parameters:
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element - the element
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Returns:
- the possible parent paths for the given element
Guidelines for using Eclipse APIs.
Copyright (c) Eclipse contributors and others 2000, 2008. All rights reserved.
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