Class NodeWalker
- java.lang.Object
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- org.apache.nutch.util.NodeWalker
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public class NodeWalker extends Object
A utility class that allows the walking of any DOM tree using a stack instead of recursion. As the node tree is walked the next node is popped off of the stack and all of its children are automatically added to the stack to be called in tree order.
Currently this class is not thread safe. It is assumed that only one thread will be accessing the
NodeWalker
at any given time.
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Constructor Summary
Constructors Constructor Description NodeWalker(Node rootNode)
Starts theNode
tree from the root node.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description Node
getCurrentNode()
Return the current node.boolean
hasNext()
Node
nextNode()
Returns the nextNode
on the stack and pushes all of its children onto the stack, allowing us to walk the node tree without the use of recursion.void
skipChildren()
Skips over and removes from the node stack the children of the last node.
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Method Detail
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nextNode
public Node nextNode()
Returns the next
Node
on the stack and pushes all of its children onto the stack, allowing us to walk the node tree without the use of recursion. If there are no more nodes on the stack then null is returned.- Returns:
- Node The next
Node
on the stack or null if there isn't a next node.
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skipChildren
public void skipChildren()
Skips over and removes from the node stack the children of the last node. When getting a next node from the walker, that node's children are automatically added to the stack. You can call this method to remove those children from the stack.
This is useful when you don't want to process deeper into the current path of the node tree but you want to continue processing sibling nodes.
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getCurrentNode
public Node getCurrentNode()
Return the current node.- Returns:
- Node
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hasNext
public boolean hasNext()
- Returns:
- returns true if there are more nodes on the current stack.
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