Package org.htmlparser.util
Class NodeTreeWalker
- java.lang.Object
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- org.htmlparser.util.NodeTreeWalker
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- All Implemented Interfaces:
NodeIterator
public class NodeTreeWalker extends java.lang.Object implements NodeIterator
A class for walking a tree ofNode
objects, in either a depth-first or breadth-first manner. The following two diagrams show the represent tree traversal with the two different methods.Depth-first traversal Breadth-first traversal - Author:
- ian_macfarlane
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Field Summary
Fields Modifier and Type Field Description protected Node
mCurrentNode
The current Node element, which will be a child of the root Node, or null.protected boolean
mDepthFirst
Whether the tree traversal method used is depth-first (default) or breadth-first.protected int
mMaxDepth
The maximum depth (child-parent links) from which this NodeTreeWalker may be removed from the root Node.protected Node
mNextNode
The next Node element after the current Node element.protected Node
mRootNode
The root Node element which defines the scope of the current tree to walk.
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Constructor Summary
Constructors Constructor Description NodeTreeWalker(Node rootNode)
Creates a new instance of NodeTreeWalker using depth-first tree traversal, without limits on how deep it may traverse.NodeTreeWalker(Node rootNode, boolean depthFirst)
Creates a new instance of NodeTreeWalker using the specified type of tree traversal, without limits on how deep it may traverse.NodeTreeWalker(Node rootNode, boolean depthFirst, int maxDepth)
Creates a new instance of NodeTreeWalker using the specified type of tree traversal and maximum depth from the root Node to traverse.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description Node
getCurrentNode()
Get the Node in the tree that the NodeTreeWalker is current at.int
getCurrentNodeDepth()
Get the number of places down that the current Node is from the root Node.int
getMaxDepth()
The maximum depth (number of child-parent links) below the root Node that this NodeTreeWalker may traverse.protected Node
getNextNodeBreadthFirst()
Traverses to the next Node from the current Node using breadth-first tree traversalprotected Node
getNextNodeDepthFirst()
Traverses to the next Node from the current Node using depth-first tree traversalNode
getRootNode()
Get the root Node that defines the scope of the tree to traverse.boolean
hasMoreNodes()
Returns whether or not there are more nodes available based on the current configuration of this NodeTreeWalker.protected void
initRootNode(Node rootNode)
Sets the root Node to be the given Node.boolean
isDepthFirst()
Whether the NodeTreeWalker is currently set to use depth-first or breadth-first tree traversal.Node
nextNode()
Traverses to the next Node from the current Node, using either depth-first or breadth-first tree traversal as appropriate.void
removeMaxDepthRestriction()
Removes any restrictions in place that prevent this NodeTreeWalker from traversing beyond a certain depth.void
reset()
Resets the current position in the tree, such that callingnextNode()
will return the first Node again.void
setCurrentNodeAsRootNode()
Sets the current Node as the root Node.void
setDepthFirst(boolean depthFirst)
Sets whether the NodeTreeWalker should use depth-first or breadth-first tree traversal.void
setRootNode(Node rootNode)
Sets the specified Node as the root Node.
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Field Detail
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mRootNode
protected Node mRootNode
The root Node element which defines the scope of the current tree to walk.
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mCurrentNode
protected Node mCurrentNode
The current Node element, which will be a child of the root Node, or null.
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mNextNode
protected Node mNextNode
The next Node element after the current Node element. Stored for internal use only.
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mMaxDepth
protected int mMaxDepth
The maximum depth (child-parent links) from which this NodeTreeWalker may be removed from the root Node. A value of -1 indicates that there is no depth restriction.
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mDepthFirst
protected boolean mDepthFirst
Whether the tree traversal method used is depth-first (default) or breadth-first.
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Constructor Detail
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NodeTreeWalker
public NodeTreeWalker(Node rootNode)
Creates a new instance of NodeTreeWalker using depth-first tree traversal, without limits on how deep it may traverse.- Parameters:
rootNode
- Node The Node to set as the root of the tree.- Throws:
java.lang.NullPointerException
- if root Node is null.
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NodeTreeWalker
public NodeTreeWalker(Node rootNode, boolean depthFirst)
Creates a new instance of NodeTreeWalker using the specified type of tree traversal, without limits on how deep it may traverse.- Parameters:
rootNode
- The Node to set as the root of the tree.depthFirst
- Whether to use depth-first (true) or breadth-first (false) tree traversal.- Throws:
java.lang.NullPointerException
- if rootNode is null.
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NodeTreeWalker
public NodeTreeWalker(Node rootNode, boolean depthFirst, int maxDepth)
Creates a new instance of NodeTreeWalker using the specified type of tree traversal and maximum depth from the root Node to traverse.- Parameters:
rootNode
- The Node to set as the root of the tree.depthFirst
- Whether to use depth-first (true) or breadth-first (false) tree traversal.maxDepth
- The maximum depth from the root Node that this NodeTreeWalker may traverse. This must be > 0 or equal to -1.- Throws:
java.lang.NullPointerException
- if rootNode is null.java.lang.IllegalArgumentException
- maxDepth is not > 0 or equal to -1.
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Method Detail
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isDepthFirst
public boolean isDepthFirst()
Whether the NodeTreeWalker is currently set to use depth-first or breadth-first tree traversal.- Returns:
- True if depth-first tree-traversal is used, or false if breadth-first tree-traversal is being used.
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setDepthFirst
public void setDepthFirst(boolean depthFirst)
Sets whether the NodeTreeWalker should use depth-first or breadth-first tree traversal.- Parameters:
depthFirst
- Whether to use depth-first (true) or breadth-first (false) tree traversal.
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getMaxDepth
public int getMaxDepth()
The maximum depth (number of child-parent links) below the root Node that this NodeTreeWalker may traverse.- Returns:
- The maximum depth that this NodeTreeWalker can traverse to.
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removeMaxDepthRestriction
public void removeMaxDepthRestriction()
Removes any restrictions in place that prevent this NodeTreeWalker from traversing beyond a certain depth.
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getRootNode
public Node getRootNode()
Get the root Node that defines the scope of the tree to traverse.- Returns:
- The root Node.
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getCurrentNode
public Node getCurrentNode()
Get the Node in the tree that the NodeTreeWalker is current at.- Returns:
- The current Node.
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setCurrentNodeAsRootNode
public void setCurrentNodeAsRootNode() throws java.lang.NullPointerException
Sets the current Node as the root Node. Resets the current position in the tree.- Throws:
java.lang.NullPointerException
- if the current Node is null (i.e. if the tree traversal has not yet begun).
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setRootNode
public void setRootNode(Node rootNode) throws java.lang.NullPointerException
Sets the specified Node as the root Node. Resets the current position in the tree.- Parameters:
rootNode
- The Node to set as the root of the tree.- Throws:
java.lang.NullPointerException
- if rootNode is null.
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reset
public void reset()
Resets the current position in the tree, such that callingnextNode()
will return the first Node again.
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nextNode
public Node nextNode()
Traverses to the next Node from the current Node, using either depth-first or breadth-first tree traversal as appropriate.- Specified by:
nextNode
in interfaceNodeIterator
- Returns:
- The next Node from the current Node.
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getCurrentNodeDepth
public int getCurrentNodeDepth()
Get the number of places down that the current Node is from the root Node. Returns 1 if current Node is a child of the root Node. Returns 0 if this NodeTreeWalker has not yet traversed to any Nodes.- Returns:
- The depth the current Node is from the root Node.
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hasMoreNodes
public boolean hasMoreNodes()
Returns whether or not there are more nodes available based on the current configuration of this NodeTreeWalker.- Specified by:
hasMoreNodes
in interfaceNodeIterator
- Returns:
- True if there are more Nodes available, based on the current configuration, or false otherwise.
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initRootNode
protected void initRootNode(Node rootNode) throws java.lang.NullPointerException
Sets the root Node to be the given Node. Resets the current position in the tree.- Parameters:
rootNode
- The Node to set as the root of the tree.- Throws:
java.lang.NullPointerException
- if rootNode is null.
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getNextNodeDepthFirst
protected Node getNextNodeDepthFirst()
Traverses to the next Node from the current Node using depth-first tree traversal- Returns:
- The next Node from the current Node using depth-first tree traversal.
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getNextNodeBreadthFirst
protected Node getNextNodeBreadthFirst()
Traverses to the next Node from the current Node using breadth-first tree traversal- Returns:
- The next Node from the current Node using breadth-first tree traversal.
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