com.espertech.esper.epl.core

Class OrderByProcessorFactoryImpl

java.lang.Object

com.espertech.esper.epl.core.OrderByProcessorFactoryImpl

All Implemented Interfaces:

OrderByProcessorFactory

public class OrderByProcessorFactoryImpl
extends Object
implements OrderByProcessorFactory

An order-by processor that sorts events according to the expressions in the order_by clause.

Constructor Summary

Constructors

Constructor and Description
OrderByProcessorFactoryImpl(List<OrderByItem> orderByList, ExprEvaluator[] groupByEvals, boolean needsGroupByKeys, boolean isSortUsingCollator, EngineImportService engineImportService, boolean onDemandQuery, String statementName) Ctor.

Method Summary

Modifier and Type	Method and Description
Comparator<Object>	getComparator()
protected static Comparator<Object>	getComparator(OrderByElement[] orderBy, boolean isSortUsingCollator) Returns a comparator for order items that may sort string values using Collator.
ExprEvaluator[]	getGroupByNodes()
OrderByElement[]	getOrderBy()
OrderByProcessor	instantiate(AggregationService aggregationService, AgentInstanceContext agentInstanceContext)
boolean	isNeedsGroupByKeys()

Methods inherited from class java.lang.Object

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

Constructor Detail

OrderByProcessorFactoryImpl

public OrderByProcessorFactoryImpl(List<OrderByItem> orderByList,
                                   ExprEvaluator[] groupByEvals,
                                   boolean needsGroupByKeys,
                                   boolean isSortUsingCollator,
                                   EngineImportService engineImportService,
                                   boolean onDemandQuery,
                                   String statementName)
                            throws ExprValidationException

Ctor.

Parameters:

orderByList - - the nodes that generate the keys to sort events on

groupByEvals - - generate the keys for determining aggregation groups

needsGroupByKeys - - indicates whether this processor needs to have individual group by keys to evaluate the sort condition successfully

isSortUsingCollator - for string value sorting using compare or Collator

statementName - statement name

engineImportService - engine imports

onDemandQuery - fire-and-forget flag

Throws:

ExprValidationException - when order-by items don't divulge a type

Method Detail

instantiate

public OrderByProcessor instantiate(AggregationService aggregationService,
                                    AgentInstanceContext agentInstanceContext)

Specified by:

instantiate in interface OrderByProcessorFactory

getOrderBy

public OrderByElement[] getOrderBy()

getGroupByNodes

public ExprEvaluator[] getGroupByNodes()

isNeedsGroupByKeys

public boolean isNeedsGroupByKeys()

getComparator

public Comparator<Object> getComparator()

getComparator

protected static Comparator<Object> getComparator(OrderByElement[] orderBy,
                                                  boolean isSortUsingCollator)
                                           throws ExprValidationException

Returns a comparator for order items that may sort string values using Collator.

Parameters:

orderBy - order-by items

isSortUsingCollator - true for Collator string sorting

Returns:

comparator

Throws:

ExprValidationException - if the return type of order items cannot be determined