com.sun.labs.minion.retrieval.parser
Class StrictTransformer

java.lang.Object
  com.sun.labs.minion.retrieval.parser.Transformer
      com.sun.labs.minion.retrieval.parser.StrictTransformer

public class StrictTransformer
extends Transformer

This class transforms the output of JavaCC into a tree of query elements that the query evaluator can understand. It's more than meets the eye.

Constructor Summary

StrictTransformer()

Method Summary

protected static java.util.ArrayList	collapseAnds(SimpleNode node, boolean passChildrenUp, int andType, int nearVal) Collapse any AND nodes that are just a chain or similar ANDSs into a single AND node with many children.
protected static java.util.ArrayList	collapseOrs(SimpleNode node, boolean passChildrenUp) Collapse any OR nodes that are just a chain or ORs into a single OR node with many children.
protected static java.util.ArrayList	collapsePassages(SimpleNode node, boolean passChildrenUp) Collapse any PASSAGE nodes that have a set of terms in an undefined node down into a single PASSAGE node.
protected static void	collapsePhrases(SimpleNode node, TokenCollectorStage tcs) Creates phrases for terms that would have been tokenized by the tokenizer upon indexing.
static java.lang.String	getFieldName(SimpleNode field)
static java.lang.String	getFieldValue(SimpleNode field)
static int	getOp(SimpleNode field)
protected static boolean	isPassThrough(SimpleNode node) Determines if the node has any significance or if it is just a passthrough that can be skipped.
static void	main(java.lang.String[] args)
protected static QueryElement	makeQueryElements(SimpleNode node, int defaultOperator) This recursive method creates the tree of query elements based on the root node passed in.
static boolean	opIsAnd(int op)
static boolean	opIsOr(int op)
protected static java.util.ArrayList	removeClutter(SimpleNode node) Removes clutter nodes -- the nodes that have only a single child and provide no additional context
QueryElement	transformTree(SimpleNode root) Transforms an abstract syntax tree provided by JJTree+JavaCC into a tree of QueryElements that can be used by the query evaluator.
QueryElement	transformTree(SimpleNode root, int defaultOperator) Transforms an abstract syntax tree provided by JJTree+JavaCC into a tree of QueryElements that can be used by the query evaluator.
protected static boolean	validateTors(SimpleNode node) Checks to make sure that any TOR nodes have only plain terms associated with them.

Methods inherited from class com.sun.labs.minion.retrieval.parser.Transformer

isDoubleQuoted, isQuoted, isSingleQuoted

Methods inherited from class java.lang.Object

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

Constructor Detail

StrictTransformer

public StrictTransformer()

Method Detail

main

public static void main(java.lang.String[] args)
                 throws java.lang.Exception

Throws:

java.lang.Exception

transformTree

public QueryElement transformTree(SimpleNode root)
                           throws java.text.ParseException

Transforms an abstract syntax tree provided by JJTree+JavaCC into a tree of QueryElements that can be used by the query evaluator.

Specified by:

transformTree in class Transformer

Parameters:

root - the root node of the tree returned from the Parser

Returns:

the root node of a tree describing a query

Throws:

java.text.ParseException

transformTree

public QueryElement transformTree(SimpleNode root,
                                  int defaultOperator)
                           throws java.text.ParseException

Transforms an abstract syntax tree provided by JJTree+JavaCC into a tree of QueryElements that can be used by the query evaluator.

Specified by:

transformTree in class Transformer

Parameters:

root - the root node of the tree returned from the Parser

defaultOperator - specified the default operator to use when no other operator is provided between terms in the query. Valid values are defined in the Searcher interface

Returns:

the root node of a tree describing a query

Throws:

java.text.ParseException

makeQueryElements

protected static QueryElement makeQueryElements(SimpleNode node,
                                                int defaultOperator)
                                         throws java.text.ParseException

This recursive method creates the tree of query elements based on the root node passed in. The tree passed in should already have been pruned as appropriate by the various methods in this class.

Parameters:

node -

defaultOperator - specified the default operator to use when no other operator is provided between terms in the query. Valid values are defined in the Searcher interface

Returns:

the top-level query element.

Throws:

java.text.ParseException

isPassThrough

protected static boolean isPassThrough(SimpleNode node)

Determines if the node has any significance or if it is just a passthrough that can be skipped.

Parameters:

node - the node to check

Returns:

true if the node is insignficant (semantically speaking)

removeClutter

protected static java.util.ArrayList removeClutter(SimpleNode node)

Removes clutter nodes -- the nodes that have only a single child and provide no additional context

Parameters:

node - the node to clean, pass in the root when calling externally

Returns:

the nodes children if the node is clutter and not the root

validateTors

protected static boolean validateTors(SimpleNode node)

Checks to make sure that any TOR nodes have only plain terms associated with them.

Parameters:

node - the node to check

Returns:

true if all TORs are valid

collapseOrs

protected static java.util.ArrayList collapseOrs(SimpleNode node,
                                                 boolean passChildrenUp)

Collapse any OR nodes that are just a chain or ORs into a single OR node with many children. Also checks to make sure that any TOR nodes have only plain terms associated with them.

Parameters:

node -

collapseAnds

protected static java.util.ArrayList collapseAnds(SimpleNode node,
                                                  boolean passChildrenUp,
                                                  int andType,
                                                  int nearVal)

Collapse any AND nodes that are just a chain or similar ANDSs into a single AND node with many children.

Parameters:

node -

collapsePassages

protected static java.util.ArrayList collapsePassages(SimpleNode node,
                                                      boolean passChildrenUp)

Collapse any PASSAGE nodes that have a set of terms in an undefined node down into a single PASSAGE node.

Parameters:

node -

collapsePhrases

protected static void collapsePhrases(SimpleNode node,
                                      TokenCollectorStage tcs)

Creates phrases for terms that would have been tokenized by the tokenizer upon indexing. Also strips quotes from terms. This method will traverse to above the leaf Term nodes and see if any of them need to be converted into Phrase nodes with individual terms hanging off of them.

Parameters:

node -

opIsOr

public static boolean opIsOr(int op)

opIsAnd

public static boolean opIsAnd(int op)

getOp

public static int getOp(SimpleNode field)
                 throws java.text.ParseException

Throws:

java.text.ParseException

getFieldName

public static java.lang.String getFieldName(SimpleNode field)
                                     throws java.text.ParseException

Throws:

java.text.ParseException

getFieldValue

public static java.lang.String getFieldValue(SimpleNode field)
                                      throws java.text.ParseException

Throws:

java.text.ParseException