public class PreOrderTraverser extends Object implements PruningTraverser
Traverser
for a
Graph
, with no cycle detection. The first node
returned is the start node, and no Edge
is traversed
to reach it. All of the caveats concerning the ordering of the
operations hasNext()
, next()
, and
remove()
detailed by the Traverser
class
documentation apply here.Constructor and Description |
---|
PreOrderTraverser(Object startNode,
Graph graph,
org.apache.commons.collections.Predicate traverserPredicate)
Creates a new
PreOrderTraverser . |
PreOrderTraverser(Object startNode,
Graph graph,
org.apache.commons.collections.Transformer traverserFactory)
Creates a new
PreOrderTraverser . |
PreOrderTraverser(Object startNode,
OrientedForest forest)
Creates a new
PreOrderTraverser , which
depth-first traverses the descendants of the specified
startNode . |
PreOrderTraverser(Object startNode,
org.apache.commons.collections.Transformer traverserFactory)
Creates a new
PreOrderTraverser . |
Modifier and Type | Method and Description |
---|---|
Graph.Edge |
getEdge()
Returns the
Edge which was traversed to get to
the last node returned by next() , or
null if no Edge was traversed. |
boolean |
hasNext() |
Object |
next() |
void |
prune()
Signals this
Traverser to not explore beyond the
last node returned by next() . |
void |
remove()
Removes from the underlying
Graph the last node
returned by next() . |
void |
removeEdge()
|
public PreOrderTraverser(Object startNode, Graph graph, org.apache.commons.collections.Predicate traverserPredicate)
PreOrderTraverser
.public PreOrderTraverser(Object startNode, OrientedForest forest)
PreOrderTraverser
, which
depth-first traverses the descendants of the specified
startNode
. The specified startNode
cannot be removed by remove()
when using this
constructor.public PreOrderTraverser(Object startNode, org.apache.commons.collections.Transformer traverserFactory)
PreOrderTraverser
. The specified
startNode
cannot be removed by remove()
when using this constructor.public void remove()
Graph
the last node
returned by next()
. This will prevent the exploration
of those nodes that would have been reached through the
removed node (unless they are reachable by another route).
This method can be called only once per call to
next()
. The behavior of this
Traverser
is unspecified if the underlying graph
structure is modified while the traversal is in progress in
any way other than by calling this method or removeEdge()
.remove
in interface Iterator
IllegalStateException
- if next()
has not
yet been called, or remove()
or
removeEdge
has been called after the last call to
next()
.public Graph.Edge getEdge()
Traverser
Edge
which was traversed to get to
the last node returned by next()
, or
null
if no Edge
was traversed. This
call can be made only if remove()
or removeEdge()
has not been called after the last
call to next()
.public void removeEdge()
Graph
the
Edge
that would be returned by getEdge()
. This will prevent the exploration of those nodes
that would have been reached through the removed
Edge
(unless they are reachable by another
route).
Description copied from interface: Traverser
Removes from the underlying Graph
the
Edge
that would be returned by getEdge()
(optional operation). If no Edge
was
traversed (as in the root of a breadth-first search), this
method throws a IllegalStateException
. This
method can be called only once per call to next()
. The behavior of a traverser is unspecified if the
underlying graph structure is modified while the traversal is
in progress in any way other than by calling this method or
remove()
.
removeEdge
in interface Traverser
public void prune()
PruningTraverser
Traverser
to not explore beyond the
last node returned by next()
. This method can
be called only once per call to next()
. After
calling this method (and before calling next()
again), remove()
, getEdge()
,
and removeEdge()
will all throw
IllegalStateExceptions
.prune
in interface PruningTraverser
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