com.yahoo.document.select.rule

Class ComparisonNode

java.lang.Object

com.yahoo.document.select.rule.ComparisonNode

All Implemented Interfaces:

ExpressionNode

public class ComparisonNode
extends Object
implements ExpressionNode

Author:

Simon Thoresen

Field Summary

Fields

Modifier and Type	Field and Description
private ExpressionNode	lhs
private String	operator
private ExpressionNode	rhs

Constructor Summary

Constructors

Constructor and Description
ComparisonNode(ExpressionNode lhs, String operator, ExpressionNode rhs) Constructs a new comparison node.

Method Summary

Modifier and Type	Method and Description
void	accept(Visitor visitor) Perform visitation of this node.
private BucketSet	compare(BucketIdFactory factory, IdNode id, LiteralNode literal, String operator)
private BucketSet	compare(BucketIdFactory factory, SearchColumnNode node, LiteralNode literal) Compares a search column node with a literal node.
Object	evaluate(Context context) Evaluate the content of this node based on document object, and return that value.
private Result	evaluateBool(Object lhs, Object rhs) Evaluate this expression on two operands, given that they are not invalid.
private Result	evaluateEquals(Object lhs, Object rhs) Compare two operands for equality.
ResultList	evaluateListAndSingle(AttributeNode.VariableValueList lhs, Object rhs)
ResultList	evaluateListsFalse(AttributeNode.VariableValueList lhs, AttributeNode.VariableValueList rhs)
ResultList	evaluateListsTrue(AttributeNode.VariableValueList lhs, AttributeNode.VariableValueList rhs)
private Result	evaluateNumber(Object lhs, Object rhs) Evalutes the value of this term over a document, given that both operands must be numbers.
private Result	evaluateString(Object lhs, Object rhs) Evalutes the value of this term over a document, given that both operands must be strings.
private ResultList	evaluateWithAtLeastOneNullSide(Object lhs, Object rhs) Evaluates a binary comparison where one or both operands are null.
private double	getAsNumber(Object value)
BucketSet	getBucketSet(BucketIdFactory factory) Returns the set of bucket ids covered by this node.
ExpressionNode	getLHS() Returns the left hand side of this comparison.
String	getOperator() Returns the comparison operator of this.
OrderingSpecification	getOrdering(IdNode lhs, LiteralNode rhs, String operator, int order)
OrderingSpecification	getOrdering(int order) If this document selection implies a specific ordering (using the orderdoc scheme), return that specification.
ExpressionNode	getRHS() Returns the right hand side of this comparison.
private String	globToRegex(char glob) Converts a single character in a glob expression to the corresponding regular expression string.
private String	globToRegex(String glob) Converts a glob pattern to a corresponding regular expression string.
ComparisonNode	setLHS(ExpressionNode lhs) Sets the left hand side of this comparison.
ComparisonNode	setOperator(String operator) Sets the comparison operator of this.
ComparisonNode	setRHS(ExpressionNode rhs) Sets the right hand side of this comparison.
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

lhs

private ExpressionNode lhs

rhs

private ExpressionNode rhs

operator

private String operator

Constructor Detail

ComparisonNode

public ComparisonNode(ExpressionNode lhs,
                      String operator,
                      ExpressionNode rhs)

Constructs a new comparison node.

Parameters:

lhs - The left-hand-side of the comparison.

operator - The comparison operator.

rhs - The right-hand-side of the comparison.

Method Detail

getLHS

public ExpressionNode getLHS()

Returns the left hand side of this comparison.

Returns:

The left hand side expression.

setLHS

public ComparisonNode setLHS(ExpressionNode lhs)

Sets the left hand side of this comparison.

Parameters:

lhs - The new left hand side.

Returns:

This, to allow chaining.

getOperator

public String getOperator()

Returns the comparison operator of this.

Returns:

The operator.

setOperator

public ComparisonNode setOperator(String operator)

Sets the comparison operator of this.

Parameters:

operator - The operator string.

Returns:

This, to allow chaining.

getRHS

public ExpressionNode getRHS()

Returns the right hand side of this comparison.

Returns:

The right hand side expression.

setRHS

public ComparisonNode setRHS(ExpressionNode rhs)

Sets the right hand side of this comparison.

Parameters:

rhs - The new right hand side.

Returns:

This, to allow chaining.

getOrdering

public OrderingSpecification getOrdering(IdNode lhs,
                                         LiteralNode rhs,
                                         String operator,
                                         int order)

getOrdering

public OrderingSpecification getOrdering(int order)

Description copied from interface: ExpressionNode

If this document selection implies a specific ordering (using the orderdoc scheme), return that specification.

Specified by:

getOrdering in interface ExpressionNode

Parameters:

order - The order in which we are looking to traverse the ordering (ASCENDING or DESCENDING)

getBucketSet

public BucketSet getBucketSet(BucketIdFactory factory)

Description copied from interface: ExpressionNode

Returns the set of bucket ids covered by this node.

Specified by:

getBucketSet in interface ExpressionNode

Parameters:

factory - The factory used by the current application.

compare

private BucketSet compare(BucketIdFactory factory,
                          SearchColumnNode node,
                          LiteralNode literal)

Compares a search column node with a literal node.

Parameters:

factory - The bucket id factory used.

node - The search column node.

literal - The literal node to compare to.

Returns:

The bucket set containing the buckets covered.

compare

private BucketSet compare(BucketIdFactory factory,
                          IdNode id,
                          LiteralNode literal,
                          String operator)

evaluate

public Object evaluate(Context context)

Description copied from interface: ExpressionNode

Evaluate the content of this node based on document object, and return that value.

Specified by:

evaluate in interface ExpressionNode

Parameters:

context - The document to evaluate over.

Returns:

The value of this.

evaluateWithAtLeastOneNullSide

private ResultList evaluateWithAtLeastOneNullSide(Object lhs,
                                                  Object rhs)

Evaluates a binary comparison where one or both operands are null. Boolean outcomes are only defined for (in)equality relations, all others return Result.INVALID. Precondition: lhs AND/OR rhs is null.

evaluateListsTrue

public ResultList evaluateListsTrue(AttributeNode.VariableValueList lhs,
                                    AttributeNode.VariableValueList rhs)

evaluateListsFalse

public ResultList evaluateListsFalse(AttributeNode.VariableValueList lhs,
                                     AttributeNode.VariableValueList rhs)

evaluateListAndSingle

public ResultList evaluateListAndSingle(AttributeNode.VariableValueList lhs,
                                        Object rhs)

evaluateBool

private Result evaluateBool(Object lhs,
                            Object rhs)

Evaluate this expression on two operands, given that they are not invalid.

Parameters:

lhs - Left hand side of operation.

rhs - Right hand side of operation.

Returns:

The evaluation result.

evaluateEquals

private Result evaluateEquals(Object lhs,
                              Object rhs)

Compare two operands for equality.

Parameters:

lhs - Left hand side of operation.

rhs - Right hand side of operation.

Returns:

Wether or not the two operands are equal.

getAsNumber

private double getAsNumber(Object value)

evaluateNumber

private Result evaluateNumber(Object lhs,
                              Object rhs)

Evalutes the value of this term over a document, given that both operands must be numbers.

Parameters:

lhs - Left hand side of operation.

rhs - Right hand side of operation.

Returns:

The evaluation result.

evaluateString

private Result evaluateString(Object lhs,
                              Object rhs)

Evalutes the value of this term over a document, given that both operands must be strings.

Parameters:

lhs - Left hand side of operation.

rhs - Right hand side of operation.

Returns:

The evaluation result.

globToRegex

private String globToRegex(String glob)

Converts a glob pattern to a corresponding regular expression string.

Parameters:

glob - The glob pattern.

Returns:

The regex string.

globToRegex

private String globToRegex(char glob)

Converts a single character in a glob expression to the corresponding regular expression string.

Parameters:

glob - The glob character.

Returns:

The regex string.

accept

public void accept(Visitor visitor)

Description copied from interface: ExpressionNode

Perform visitation of this node.

Specified by:

accept in interface ExpressionNode

Parameters:

visitor - The visitor that wishes to visit the node.

toString

public String toString()

Overrides:

toString in class Object