| Manages expanded/collapsed paths for the Outline. Provides services similar
to those JTree implements inside its own class body. Propagates changes
in expanded state to the layout cache.
Principally what this class does is manage the state of expanded paths which
are not visible, or whose parents have been closed/opened. Whereas the
layout cache retains information only about what is visibly expanded, this
class manages information about any path that has been expanded at some
point in the lifetime of an Outline, so that for example, if A contains B
contains C, and A and B and C are expanded, then the user collapses A,
and later reëexpands A, B and C will retain their expanded state and
appear as they did the last time A was expanded.
When nodes are removed, the OutlineModel must call removePath() for any
defunct paths to avoid memory leaks by the TreePathSupport holding
references to defunct nodes and not allowing them to be garbage collected.
Its addTreeWillExpandListener code supports
ExtTreeWillExpandListener, so such a listener may be notified
if some other listener vetos a pending expansion event.
author:
Tim Boudreau |
