com.espertech.esper.epl.agg.service

Class AggregationValidationContext

java.lang.Object

com.espertech.esper.epl.agg.service.AggregationValidationContext

public class AggregationValidationContext
extends Object

Context for use with plug-in custom aggregation functions that implement AggregationFunctionFactory.

This context object provides access to the parameter expressions themselves as well as information compiled from the parameter expressions for your convenience.

Constructor Summary

Constructors

Constructor and Description
AggregationValidationContext(Class[] parameterTypes, boolean[] constantValue, Object[] constantValues, boolean distinct, boolean windowed, ExprNode[] expressions, LinkedHashMap<String,List<ExprNode>> namedParameters) Ctor.

Method Summary

Modifier and Type	Method and Description
Object[]	getConstantValues() If a parameter expression returns a constant value, the value of the constant it returns is provided in this array.
ExprNode[]	getExpressions() Returns the parameter expressions themselves for interrogation.
boolean[]	getIsConstantValue() A boolean indicator for each parameter expression that is true if the expression returns a constant result or false if the expression result is not a constant value.
LinkedHashMap<String,List<ExprNode>>	getNamedParameters() Returns any named parameters or null if there are no named parameters
Class[]	getParameterTypes() The return type of each parameter expression.
boolean	isDistinct() Returns true to indicate that the 'distinct' keyword was specified for this aggregation function.
boolean	isWindowed() Returns true to indicate that all parameter expressions return event properties that originate from a stream that provides a remove stream.

Methods inherited from class java.lang.Object

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

Constructor Detail

AggregationValidationContext

public AggregationValidationContext(Class[] parameterTypes,
                                    boolean[] constantValue,
                                    Object[] constantValues,
                                    boolean distinct,
                                    boolean windowed,
                                    ExprNode[] expressions,
                                    LinkedHashMap<String,List<ExprNode>> namedParameters)

Ctor.

Parameters:

parameterTypes - the type of each parameter expression.

constantValue - for each parameter expression an indicator whether the expression returns a constant result

constantValues - for each parameter expression that returns a constant result this array contains the constant value

distinct - true if 'distinct' keyword was provided

windowed - true if all event properties references by parameter expressions are from streams that have data windows declared onto the stream or are from named windows

expressions - the parameter expressions themselves (positional parameters only)

namedParameters - provided when there are named parameters, such as the "filter:expression" parameter

Method Detail

getParameterTypes

public Class[] getParameterTypes()

The return type of each parameter expression.

This information can also be obtained by calling getType on each parameter expression.

Returns:

array providing result type of each parameter expression

getIsConstantValue

public boolean[] getIsConstantValue()

A boolean indicator for each parameter expression that is true if the expression returns a constant result or false if the expression result is not a constant value.

This information can also be obtained by calling isConstantResult on each parameter expression.

Returns:

array providing an indicator per parameter expression that the result is a constant value

getConstantValues

public Object[] getConstantValues()

If a parameter expression returns a constant value, the value of the constant it returns is provided in this array.

This information can also be obtained by calling evaluate on each parameter expression providing a constant value.

Returns:

array providing the constant return value per parameter expression that has constant result value, or null if a parameter expression is deemded to not provide a constant result value

isDistinct

public boolean isDistinct()

Returns true to indicate that the 'distinct' keyword was specified for this aggregation function.

Returns:

distinct value indicator

isWindowed

public boolean isWindowed()

Returns true to indicate that all parameter expressions return event properties that originate from a stream that provides a remove stream.

Returns:

windowed indicator

getExpressions

public ExprNode[] getExpressions()

Returns the parameter expressions themselves for interrogation.

Returns:

parameter expressions

getNamedParameters

public LinkedHashMap<String,List<ExprNode>> getNamedParameters()

Returns any named parameters or null if there are no named parameters

Returns:

named parameters