it.uniroma2.sag.kelp.data.manipulator

Class TreeNodePruner

java.lang.Object

it.uniroma2.sag.kelp.data.manipulator.TreeNodePruner

All Implemented Interfaces:

Manipulator

public class TreeNodePruner
extends Object
implements Manipulator

A manipulator for performing pruning on a tree. Roughly speaking the class performs a visit of the tree and, for each node, checks whether it should be pruned. The behavior of the class depends on the classes passed as parameters to the constructor. However, a general schema is as follows: 1) one or few nodes of the tree are selected, the visit of the tree will start from such nodes (depends on nodeSelectorObj) 2) the visit can be pre-order or post-order and a limit to the number of recursive calls can be set (depends on visit and maxDepthVisitsWhilePruning 3) a class for checking whether a node has to be pruned (nodePrunerObj); optionally a second class for pruning non leaf nodes only can be provided (internalNodePrunerObj) When dealing with ExamplePair objects, it is possible to apply a pruning strategy to the trees of one pair Example of the pair only (in this case class treeSelectorObj need to be set up properly)

Author:

Giovanni Da San Martino Contributor Alessandro Moschitti

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	TreeNodePruner.visitType

Field Summary

Fields

Modifier and Type	Field and Description
static int	NO_DISTANCE_CONSTRAINT
static int	UNLIMITED_RECURSION

Constructor Summary

Constructors

Constructor and Description
TreeNodePruner(NodePruner nodePrunerForPreOrderVisit, SelectRepresentationFromExample treeSelectorInExample, TreeNodeSelector nodeSelectorObj, int maxDepthVisitsWhilePruning) Create a tree pruner which performs a pre-order traversal of the tree.
TreeNodePruner(NodePruner nodePrunerForPreOrderVisit, String representationName, TreeNodeSelector nodeSelectorObj, int maxDepthVisitsWhilePruning) Create a tree pruner which performs a pre-order traversal of the tree.
TreeNodePruner(NodeToBePrunedCheckerAbstractClass nodePrunerObj, SelectRepresentationFromExample treeSelectorInExample, NodeToBePrunedCheckerAbstractClass internalNodePrunerObj, TreeNodeSelector nodeSelectorObj, int maxDepthVisitsWhilePruning) Create a tree pruner which performs a post-order traversal of the tree.
TreeNodePruner(NodeToBePrunedCheckerAbstractClass nodePrunerObj, String representationName)
TreeNodePruner(NodeToBePrunedCheckerAbstractClass nodePrunerObj, String representationName, boolean applyToLeftExampleInPair)
TreeNodePruner(NodeToBePrunedCheckerAbstractClass nodePrunerObj, String representationName, NodeToBePrunedCheckerAbstractClass internalNodePrunerObj, TreeNodeSelector nodeSelectorObj, int maxDepthVisitsWhilePruning)

Method Summary

Methods

Modifier and Type	Method and Description
void	applyPruningToLeftElementOfExamplePair()
void	applyPruningToRightElementOfExamplePair()
String	describe() Describe what the elements of the tree-pruner will do once the manipulator is invoked.
void	manipulate(Example example)
void	pruneTree(TreeRepresentation tree)
void	setMaximumDepthOfVisits(int maxDepth)
void	setVisitTypePostOrder()
void	setVisitTypePreOrder()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

UNLIMITED_RECURSION

public static final int UNLIMITED_RECURSION

See Also:

Constant Field Values

NO_DISTANCE_CONSTRAINT

public static final int NO_DISTANCE_CONSTRAINT

See Also:

Constant Field Values

Constructor Detail

TreeNodePruner

public TreeNodePruner(NodeToBePrunedCheckerAbstractClass nodePrunerObj,
              SelectRepresentationFromExample treeSelectorInExample,
              NodeToBePrunedCheckerAbstractClass internalNodePrunerObj,
              TreeNodeSelector nodeSelectorObj,
              int maxDepthVisitsWhilePruning)

Create a tree pruner which performs a post-order traversal of the tree.

Parameters:

nodePrunerObj - an object for establishing whether a node has to be pruned

treeSelectorObj - an object for selecting trees from an Example

internalNodePrunerObj - an object for establishing whether an internal node of the tree has to be pruned

nodeSelectorObj - an object for selecting a list of nodes from which the visit of the tree will start

maxDepthVisitsWhilePruning - maximum number of recursive calls when visiting a tree

TreeNodePruner

public TreeNodePruner(NodePruner nodePrunerForPreOrderVisit,
              SelectRepresentationFromExample treeSelectorInExample,
              TreeNodeSelector nodeSelectorObj,
              int maxDepthVisitsWhilePruning)

Create a tree pruner which performs a pre-order traversal of the tree.

Parameters:

nodePrunerForPreOrderVisit - an object performing the pruning of a node

nodeSelectorObj - an object for selecting a list of nodes from which the visit of the tree will start

maxDepthVisitsWhilePruning - maximum number of recursive calls when visiting a tree

TreeNodePruner

public TreeNodePruner(NodeToBePrunedCheckerAbstractClass nodePrunerObj,
              String representationName,
              NodeToBePrunedCheckerAbstractClass internalNodePrunerObj,
              TreeNodeSelector nodeSelectorObj,
              int maxDepthVisitsWhilePruning)

TreeNodePruner

public TreeNodePruner(NodeToBePrunedCheckerAbstractClass nodePrunerObj,
              String representationName)

TreeNodePruner

public TreeNodePruner(NodeToBePrunedCheckerAbstractClass nodePrunerObj,
              String representationName,
              boolean applyToLeftExampleInPair)

TreeNodePruner

public TreeNodePruner(NodePruner nodePrunerForPreOrderVisit,
              String representationName,
              TreeNodeSelector nodeSelectorObj,
              int maxDepthVisitsWhilePruning)

Create a tree pruner which performs a pre-order traversal of the tree.

Parameters:

nodePrunerForPreOrderVisit - an object performing the pruning of a node

representationName - name of the representation of the trees in the Example

nodeSelectorObj - an object for selecting a list of nodes from which the visit of the tree will start

maxDepthVisitsWhilePruning - maximum number of recursive calls when visiting a tree

Method Detail

applyPruningToLeftElementOfExamplePair

public void applyPruningToLeftElementOfExamplePair()

applyPruningToRightElementOfExamplePair

public void applyPruningToRightElementOfExamplePair()

describe

public String describe()

Describe what the elements of the tree-pruner will do once the manipulator is invoked.

Returns:

a String with the description

manipulate

public void manipulate(Example example)

Specified by:

manipulate in interface Manipulator

pruneTree

public void pruneTree(TreeRepresentation tree)

setMaximumDepthOfVisits

public void setMaximumDepthOfVisits(int maxDepth)

setVisitTypePostOrder

public void setVisitTypePostOrder()

setVisitTypePreOrder

public void setVisitTypePreOrder()