Package com.yahoo.document.select.rule

Class LogicNode

java.lang.Object

com.yahoo.document.select.rule.LogicNode

All Implemented Interfaces:

ExpressionNode

public class LogicNode
extends java.lang.Object
implements ExpressionNode

This class defines a logical expression of nodes. This implementation uses a stack to evaluate its content as to avoid deep recursions when building the parse tree.

Author:

Simon Thoresen Hult

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
class	LogicNode.NodeItem	Private class to store expression nodes in a stack.

Field Summary

Fields

Modifier and Type	Field	Description
static int	AND
static int	NOP
static int	OR

Constructor Summary

Constructors

Constructor	Description
LogicNode()	Construct an empty logic expression.

Method Summary

Modifier and Type	Method	Description
void	accept(Visitor visitor)	Perform visitation of this node.
LogicNode	add(java.lang.String operator, ExpressionNode node)	Adds an (operator, node) pair to this expression.
java.lang.Object	evaluate(Context context)	Evaluate the content of this node based on document object, and return that value.
BucketSet	getBucketSet(BucketIdFactory factory)	Returns the set of bucket ids covered by this node.
java.util.List<LogicNode.NodeItem>	getItems()
OrderingSpecification	getOrdering(int order)	If this document selection implies a specific ordering (using the orderdoc scheme), return that specification.
java.lang.String	operatorToString(int operator)	Converts the given operator index to a string representation.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

NOP

public static final int NOP

See Also:

Constant Field Values

OR

public static final int OR

See Also:

Constant Field Values

AND

public static final int AND

See Also:

Constant Field Values

Constructor Detail

LogicNode

public LogicNode()

Construct an empty logic expression.

Method Detail

getItems

public java.util.List<LogicNode.NodeItem> getItems()

add

public LogicNode add(java.lang.String operator,
                     ExpressionNode node)

Adds an (operator, node) pair to this expression.

Parameters:

operator - The operator that combines the previous with the node given.

node - The node to add to this.

Returns:

This, to allow chaining.

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.

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)

evaluate

public java.lang.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.

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 java.lang.String toString()

Overrides:

toString in class java.lang.Object

operatorToString

public java.lang.String operatorToString(int operator)

Converts the given operator index to a string representation.

Parameters:

operator - The operator index to convert.

Returns:

The string representation.