com.endeca.navigation.analytics

Class Select

java.lang.Object

com.endeca.navigation.analytics.Select

All Implemented Interfaces:

QueryNode

public class Select
extends Object
implements QueryNode

A Select operation represents the assignment of a named derived value to a record produced as the result of a Statement. The definition of the derived value is given by an expression.

Constructor Summary

Constructors

Constructor and Description
Select(String field, Expr expr) Constructs a new Select which will associate the result of expr with the derived property named field.

Method Summary

Modifier and Type	Method and Description
Expr	getExpr() Gets the derived property expression for this Select.
String	getFieldName() Gets the name of the derived property that this Select should produce.
void	setExpr(Expr expr) Sets the derived property expression for this Select.
void	setFieldName(String name) Sets the name of the derived property that this Select should produce.
String	toString() Returns the string form of this Select.
String	toWire() Returns the wire format of this Select.
void	validateSyntax() Validates the syntax of this Select.

Methods inherited from class java.lang.Object

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

Constructor Detail

Select

public Select(String field,
              Expr expr)

Constructs a new Select which will associate the result of expr with the derived property named field.

Parameters:

field - the name of the derived property.

expr - an expression object of type Expr.

Method Detail

setFieldName

public void setFieldName(String name)

Sets the name of the derived property that this Select should produce.

Parameters:

name - the name of the derived property.

getFieldName

public String getFieldName()

Gets the name of the derived property that this Select should produce.

Returns:

The name of the derived property.

setExpr

public void setExpr(Expr expr)

Sets the derived property expression for this Select.

Parameters:

expr - an expression object of type Expr.

getExpr

public Expr getExpr()

Gets the derived property expression for this Select.

Returns:

The derived property expression as an object of type Expr.

toString

public String toString()

Returns the string form of this Select. These are of the format:

expression AS derived-prop-name

For example:

AVG(Amount) / MAX(Amount) AS AvgOverMax

is returned if the derived property name is "AvgOverMax" and the expression assigns the ratio of the average "Amount" value to the maximum "Amount" value.

Specified by:

toString in interface QueryNode

Overrides:

toString in class Object

Returns:

A string representation of this Select in the specified format.

toWire

public String toWire()

Returns the wire format of this Select. This method is not intended for public use because the wire format is subject to change.

Specified by:

toWire in interface QueryNode

Returns:

A wire format representation of this Select.

validateSyntax

public void validateSyntax()
                    throws SyntaxException

Validates the syntax of this Select. A Select is valid if the derived property name is non-null and non-empty and the expression is itself valid.

Specified by:

validateSyntax in interface QueryNode

Throws:

SyntaxException - if the syntax requirements are not satisfied.