public class NodeTreeWalker extends Object
A class providing different algorithms for traversing a hierarchy of configuration nodes.
The methods provided by this class accept a ConfigurationNodeVisitor
and visit all nodes in a hierarchy
starting from a given root node. Because a NodeHandler
has to be passed in, too, arbitrary types of nodes can
be processed. The walk()
methods differ in the order in which nodes are visited. Details can be found in the
method documentation.
An instance of this class does not define any state; therefore, it can be shared and used concurrently. The
INSTANCE
member field can be used for accessing a default instance. If desired (e.g. for testing purposes),
new instances can be created.
Modifier and Type | Field and Description |
---|---|
static NodeTreeWalker |
INSTANCE
The default instance of this class.
|
Constructor and Description |
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NodeTreeWalker() |
Modifier and Type | Method and Description |
---|---|
<T> void |
walkBFS(T root,
ConfigurationNodeVisitor<T> visitor,
NodeHandler<T> handler)
Visits all nodes in the hierarchy represented by the given root node in breadth first search manner.
|
<T> void |
walkDFS(T root,
ConfigurationNodeVisitor<T> visitor,
NodeHandler<T> handler)
Visits all nodes in the hierarchy represented by the given root node in depth first search manner.
|
public static final NodeTreeWalker INSTANCE
public NodeTreeWalker()
public <T> void walkDFS(T root, ConfigurationNodeVisitor<T> visitor, NodeHandler<T> handler)
ConfigurationNodeVisitor.visitBeforeChildren(Object, NodeHandler)
is called on a node, then
recursively all of its children are processed, and eventually
ConfigurationNodeVisitor.visitAfterChildren(Object, NodeHandler)
gets invoked.T
- the type of the nodes involvedroot
- the root node of the hierarchy to be processed (may be null, then this call has no effect)visitor
- the ConfigurationNodeVisitor
(must not be null)handler
- the NodeHandler
(must not be null)IllegalArgumentException
- if a required parameter is nullpublic <T> void walkBFS(T root, ConfigurationNodeVisitor<T> visitor, NodeHandler<T> handler)
visitBeforeChildren()
method gets called!.T
- the type of the nodes involvedroot
- the root node of the hierarchy to be processed (may be null, then this call has no effect)visitor
- the ConfigurationNodeVisitor
(must not be null)handler
- the NodeHandler
(must not be null)IllegalArgumentException
- if a required parameter is nullCopyright © 2001–2022 The Apache Software Foundation. All rights reserved.