edu.stanford.nlp.trees

Class TreeGraphNode

java.lang.Object

java.util.AbstractCollection<Tree>

edu.stanford.nlp.trees.Tree

edu.stanford.nlp.trees.TreeGraphNode

All Implemented Interfaces:

Label, HasParent, Labeled, Scored, Serializable, Iterable<Tree>, Collection<Tree>

public class TreeGraphNode
extends Tree
implements HasParent

A TreeGraphNode is simply a Tree with some additional functionality. For example, the parent() method works without searching from the root. Labels are always assumed to be CoreLabel

This class makes the horrible mistake of changing the semantics of equals and hashCode to go back to "==" and System.identityHashCode, despite the semantics of the superclass's equality.

Author:

Bill MacCartney

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected TreeGraphNode[]	children Children of this node.
protected CoreLabel	label Label for this node.
protected TreeGraphNode	parent Parent of this node.
protected GrammaticalStructure	tg The GrammaticalStructure of which this node is part.
protected static TreeGraphNode[]	ZERO_TGN_CHILDREN A leaf node should have a zero-length array for its children.

Fields inherited from class edu.stanford.nlp.trees.Tree

EMPTY_TREE_ARRAY

Constructor Summary

Constructors

Modifier	Constructor and Description
	TreeGraphNode() Create a new empty TreeGraphNode.
	TreeGraphNode(Label label) Create a new TreeGraphNode with the supplied label.
	TreeGraphNode(Label label, List<Tree> children) Create a new TreeGraphNode with the supplied label and list of child nodes.
	TreeGraphNode(Tree t, GrammaticalStructure graph) Create a new TreeGraphNode having the same tree structure and label values as an existing tree (but no shared storage).
	TreeGraphNode(TreeGraphNode t)
protected	TreeGraphNode(Tree t, TreeGraphNode parent) Create a new TreeGraphNode having the same tree structure and label values as an existing tree (but no shared storage).

Method Summary

Modifier and Type	Method and Description
TreeGraphNode[]	children() Returns an array of the children of this node.
boolean	equals(Object o) Implements equality for TreeGraphNodes.
static TreeFactory	factory() Return a TreeFactory that produces trees of type TreeGraphNode.
static TreeFactory	factory(LabelFactory lf) Return a TreeFactory that produces trees of type TreeGraphNode, with the Label made by the supplied LabelFactory.
int	hashCode() Implements a hashCode for Tree's.
TreeGraphNode	headTagNode() Return the node containing the head tag for this node (or null if none), as recorded in this node's CoreLabel.
TreeGraphNode	headWordNode() Return the node containing the head word for this node (or null if none), as recorded in this node's CoreLabel.
TreeGraphNode	highestNodeWithSameHead() Checks the node's ancestors to find the highest ancestor with the same headWordNode as this node.
int	index() Get the index for the current node.
CoreLabel	label() Returns the label associated with the current node, or null if there is no label.
static void	main(String[] args) Just for testing.
TreeGraphNode	parent() Get the parent for the current node.
void	percolateHeads(HeadFinder hf) Uses the specified HeadFinder to determine the heads for this node and all its descendants, and to store references to the head word node and head tag node in this node's CoreLabel and the CoreLabels of all its descendants.
void	setChildren(List<? extends Tree> childTreesList) Set the children of this tree node to the given list.
void	setChildren(Tree[] children) Sets the children of this TreeGraphNode.
protected void	setIndex(int index) Set the index for the current node.
void	setLabel(CoreLabel label) Sets the label associated with the current node.
void	setParent(TreeGraphNode parent) Set the parent for the current node.
protected void	setTreeGraph(GrammaticalStructure tg) Set pointer to the GrammaticalStructure of which this node is a part.
String	toOneLineString() Returns a String representation of this node and its subtree as a one-line parenthesized list.
String	toPrettyString(int indentLevel) Returns a String representation of this node and its subtree with one node per line, indented according to indentLevel.
String	toPrimes()
String	toString() Converts parse tree to string in Penn Treebank format.
String	toString(CoreLabel.OutputFormat format)
TreeFactory	treeFactory() Returns a TreeFactory that produces TreeGraphNodes.
protected GrammaticalStructure	treeGraph() Get the GrammaticalStructure of which this node is a part.

Methods inherited from class edu.stanford.nlp.trees.Tree

addChild, addChild, ancestor, cCommands, constituents, constituents, constituents, constituents, constituents, deepCopy, deepCopy, deepCopy, dependencies, dependencies, dependencies, depth, depth, dominates, dominationPath, firstChild, flatten, flatten, getChild, getChildrenAsList, getLeaves, getLeaves, getNodeNumber, getSpan, headPreTerminal, headTerminal, headTerminal, indentedListPrint, indentedListPrint, indentedXMLPrint, indentedXMLPrint, indexLeaves, indexLeaves, indexLeaves, indexSpans, indexSpans, indexSpans, insertDtr, isLeaf, isPhrasal, isPrePreTerminal, isPreTerminal, isUnaryRewrite, iterator, joinNode, labeledYield, labeledYield, labelFactory, labels, lastChild, leftCharEdge, localTree, localTrees, mapDependencies, mapDependencies, nodeNumber, nodeString, numChildren, objectIndexOf, parent, pathNodeToNode, pennPrint, pennPrint, pennPrint, pennPrint, pennPrint, pennString, percolateHeadAnnotations, percolateHeadIndices, postOrderNodeList, preOrderNodeList, preTerminalYield, preTerminalYield, printLocalTree, printLocalTree, prune, prune, removeChild, rightCharEdge, score, setChild, setFromString, setLabel, setLabels, setScore, setSpans, setValue, siblings, size, skipRoot, spliceOut, spliceOut, subTreeList, subTrees, subTrees, taggedLabeledYield, taggedYield, taggedYield, toStringBuilder, toStringBuilder, transform, transform, treeSkeletonCopy, treeSkeletonCopy, upperMostUnary, value, valueOf, valueOf, yield, yield, yield, yieldHasWord, yieldHasWord, yieldWords, yieldWords

Methods inherited from class java.util.AbstractCollection

add, addAll, clear, contains, containsAll, isEmpty, remove, removeAll, retainAll, toArray, toArray

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Collection

parallelStream, removeIf, spliterator, stream

Methods inherited from interface java.lang.Iterable

forEach

Field Detail

label

protected CoreLabel label

Label for this node.

parent

protected TreeGraphNode parent

Parent of this node.

children

protected TreeGraphNode[] children

Children of this node.

tg

protected GrammaticalStructure tg

The GrammaticalStructure of which this node is part.

ZERO_TGN_CHILDREN

protected static final TreeGraphNode[] ZERO_TGN_CHILDREN

A leaf node should have a zero-length array for its children. For efficiency, subclasses can use this array as a return value for children() for leaf nodes if desired. Should this be public instead?

Constructor Detail

TreeGraphNode

public TreeGraphNode()

Create a new empty TreeGraphNode.

TreeGraphNode

public TreeGraphNode(Label label)

Create a new TreeGraphNode with the supplied label.

Parameters:

label - the label for this node.

TreeGraphNode

public TreeGraphNode(Label label,
                     List<Tree> children)

Create a new TreeGraphNode with the supplied label and list of child nodes.

Parameters:

label - the label for this node.

children - the list of child TreeGraphNodes for this node.

TreeGraphNode

public TreeGraphNode(Tree t,
                     GrammaticalStructure graph)

Create a new TreeGraphNode having the same tree structure and label values as an existing tree (but no shared storage).

Parameters:

t - the tree to copy

graph - the graph of which this node is a part

TreeGraphNode

public TreeGraphNode(TreeGraphNode t)

TreeGraphNode

protected TreeGraphNode(Tree t,
                        TreeGraphNode parent)

Create a new TreeGraphNode having the same tree structure and label values as an existing tree (but no shared storage). Operates recursively to construct an entire subtree.

Parameters:

t - the tree to copy

parent - the parent node

Method Detail

equals

public boolean equals(Object o)

Implements equality for TreeGraphNodes. Unlike Trees, TreeGraphNodes should be considered equal only if they are ==. Implementation note: TODO: This should be changed via introducing a Tree interface with the current Tree and this class implementing it, since what is done here breaks the equals() contract.

Specified by:

equals in interface Collection<Tree>

Overrides:

equals in class Tree

Parameters:

o - The object to compare with

Returns:

Whether two things are equal

hashCode

public int hashCode()

Description copied from class: Tree

Implements a hashCode for Tree's. Two trees should have the same hashcode if they are equal, so we hash on the label value and the children's label values.

Specified by:

hashCode in interface Collection<Tree>

Overrides:

hashCode in class Tree

Returns:

The hash code

label

public CoreLabel label()

Returns the label associated with the current node, or null if there is no label.

Specified by:

label in interface Labeled

Overrides:

label in class Tree

Returns:

the label of the node

setLabel

public void setLabel(CoreLabel label)

Sets the label associated with the current node.

Parameters:

label - the new label to use.

index

public int index()

Get the index for the current node.

setIndex

protected void setIndex(int index)

Set the index for the current node.

parent

public TreeGraphNode parent()

Get the parent for the current node.

Specified by:

parent in interface HasParent

Overrides:

parent in class Tree

Returns:

The parent Tree node or null

See Also:

Tree.parent(Tree)

setParent

public void setParent(TreeGraphNode parent)

Set the parent for the current node.

children

public TreeGraphNode[] children()

Returns an array of the children of this node.

Specified by:

children in class Tree

Returns:

The children of the node

See Also:

Tree.getChildrenAsList()

setChildren

public void setChildren(Tree[] children)

Sets the children of this TreeGraphNode. If given null, this method sets the node's children to the canonical zero-length Tree[] array.

Overrides:

setChildren in class Tree

Parameters:

children - an array of child trees

See Also:

Tree.setChildren(List)

setChildren

public void setChildren(List<? extends Tree> childTreesList)

Set the children of this tree node to the given list. This method is implemented in the Tree class by converting the List into a tree array and calling the array-based method. Subclasses which use a List-based representation of tree children should override this method. This implementation allows the case that the List is null: it yields a node with no children (represented by a canonical zero-length children() array).

Overrides:

setChildren in class Tree

Parameters:

childTreesList - A list of trees to become children of the node. This method does not retain the List that you pass it (copying is done), but it will retain the individual children (they are not copied).

See Also:

Tree.setChildren(Tree[])

treeGraph

protected GrammaticalStructure treeGraph()

Get the GrammaticalStructure of which this node is a part.

setTreeGraph

protected void setTreeGraph(GrammaticalStructure tg)

Set pointer to the GrammaticalStructure of which this node is a part. Operates recursively to set pointer for all descendants too.

percolateHeads

public void percolateHeads(HeadFinder hf)

Uses the specified HeadFinder to determine the heads for this node and all its descendants, and to store references to the head word node and head tag node in this node's CoreLabel and the CoreLabels of all its descendants.

Note that, in contrast to Tree.percolateHeads(), which assumes CategoryWordTag labels and therefore stores head words and head tags merely as Strings, this method stores references to the actual nodes. This mitigates potential problems in sentences which contain the same word more than once.

Overrides:

percolateHeads in class Tree

Parameters:

hf - The headfinding algorithm to use

headWordNode

public TreeGraphNode headWordNode()

Return the node containing the head word for this node (or null if none), as recorded in this node's CoreLabel. (In contrast to CategoryWordTag, we store head words and head tags as references to nodes, not merely as Strings.)

Returns:

the node containing the head word for this node

headTagNode

public TreeGraphNode headTagNode()

Return the node containing the head tag for this node (or null if none), as recorded in this node's CoreLabel. (In contrast to CategoryWordTag, we store head words and head tags as references to nodes, not merely as Strings.)

Returns:

the node containing the head tag for this node

highestNodeWithSameHead

public TreeGraphNode highestNodeWithSameHead()

Checks the node's ancestors to find the highest ancestor with the same headWordNode as this node.

treeFactory

public TreeFactory treeFactory()

Returns a TreeFactory that produces TreeGraphNodes. The Label of this is examined, and providing it is not null, a LabelFactory which will produce that kind of Label is supplied to the TreeFactory. If the Label is null, a CoreLabel.factory() will be used. The factories returned on different calls are different: a new one is allocated each time.

Specified by:

treeFactory in class Tree

Returns:

a factory to produce treegraphs

factory

public static TreeFactory factory()

Return a TreeFactory that produces trees of type TreeGraphNode. The factory returned is always the same one (a singleton).

Returns:

a factory to produce treegraphs

factory

public static TreeFactory factory(LabelFactory lf)

Return a TreeFactory that produces trees of type TreeGraphNode, with the Label made by the supplied LabelFactory. The factory returned is a different one each time.

Parameters:

lf - The LabelFactory to use

Returns:

a factory to produce treegraphs

toPrettyString

public String toPrettyString(int indentLevel)

Returns a String representation of this node and its subtree with one node per line, indented according to indentLevel.

Parameters:

indentLevel - how many levels to indent (0 for root node)

Returns:

String representation of this subtree

toOneLineString

public String toOneLineString()

Returns a String representation of this node and its subtree as a one-line parenthesized list.

Returns:

String representation of this subtree

toPrimes

public String toPrimes()

toString

public String toString()

Description copied from class: Tree

Converts parse tree to string in Penn Treebank format.

Implementation note: Internally, the method gains efficiency by chaining use of a single StringBuilder through all the printing.

Specified by:

toString in interface Label

Overrides:

toString in class Tree

Returns:

the tree as a bracketed list on one line

toString

public String toString(CoreLabel.OutputFormat format)

main

public static void main(String[] args)

Just for testing.