Package com.yahoo.search.grouping.request

Class GroupingExpression

java.lang.Object

com.yahoo.search.grouping.request.GroupingNode

com.yahoo.search.grouping.request.GroupingExpression

Direct Known Subclasses:

AggregatorNode, BucketValue, ConstantValue, DocumentValue, FunctionNode

public abstract class GroupingExpression
extends GroupingNode

This class represents an expression in a GroupingOperation. You may manually construct this expression, or you may use the GroupingParser to generate one from a query-string.

Author:

Simon Thoresen Hult

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	GroupingExpression(String image, String label, Integer level)

Method Summary

Modifier and Type	Method	Description
static String	asImage(Object obj)	Returns a string representation of an object that can be used in the 'image' constructor argument of GroupingNode.
static String	asString(List<GroupingExpression> lst)	Returns a string description of the given list of expressions.
abstract GroupingExpression	copy()	Returns a deep copy of this
int	getLevel()	Returns the conceptual level of this expression.
protected Integer	getLevelOrNull()
void	resolveLevel(int level)	Resolves the conceptual level of this expression.
GroupingExpression	setLabel(String label)	Assigns a label to this grouping expression.
void	visit(ExpressionVisitor visitor)	Recursively calls ExpressionVisitor.visitExpression(GroupingExpression) for this expression and all of its argument expressions.

Methods inherited from class com.yahoo.search.grouping.request.GroupingNode

getImage, getLabel, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

GroupingExpression

protected GroupingExpression(String image,
                             String label,
                             Integer level)

Method Detail

copy

public abstract GroupingExpression copy()

Returns a deep copy of this

resolveLevel

public void resolveLevel(int level)

Resolves the conceptual level of this expression. This level represents the type of data that is consumed by this expression, where level 0 is a single hit, level 1 is a group, level 2 is a list of groups, and so forth. This method verifies the input level against the expression type, and recursively resolves the level of all argument expressions.

Parameters:

level - The level of the input data.

Throws:

IllegalArgumentException - Thrown if the level of this expression could not be resolved.

IllegalStateException - Thrown if type failed to accept the number of arguments provided.

getLevel

public int getLevel()

Returns the conceptual level of this expression.

Returns:

the level.

Throws:

IllegalArgumentException - thrown if the level of this expression has not been resolved.

See Also:

resolveLevel(int)

getLevelOrNull

protected final Integer getLevelOrNull()

visit

public void visit(ExpressionVisitor visitor)

Recursively calls ExpressionVisitor.visitExpression(GroupingExpression) for this expression and all of its argument expressions.

Parameters:

visitor - The visitor to call.

asString

public static String asString(List<GroupingExpression> lst)

Returns a string description of the given list of expressions. This is a comma-separated list of the expressions own GroupingNode.toString() output.

Parameters:

lst - The list of expressions to output.

Returns:

The string description.

asImage

public static String asImage(Object obj)

Returns a string representation of an object that can be used in the 'image' constructor argument of GroupingNode. This method ensures that strings are quoted, and that all complex characters are escaped.

Parameters:

obj - The object to output.

Returns:

The string representation.

setLabel

public GroupingExpression setLabel(String label)

Description copied from class: GroupingNode

Assigns a label to this grouping expression. The label is applied to the results of this expression so that they can be identified by the caller when processing the output.

Overrides:

setLabel in class GroupingNode

Parameters:

label - The label to assign to this.

Returns:

This, to allow chaining.