Uses of Interface
com.espertech.esper.util.MetaDefItem

Packages that use MetaDefItem

Package	Description
com.espertech.esper.client	This package and its sub-packages defines the central Esper Client APIs.
com.espertech.esper.client.soda	This package defines the Esper statement object model.
com.espertech.esper.collection	Internal collection classes
com.espertech.esper.core.service	Implementation of client package interfaces, glue code
com.espertech.esper.epl.declexpr	Declared expression handling.
com.espertech.esper.epl.enummethod.dot	Enumeration method utility classes and input data sources.
com.espertech.esper.epl.expression.accessagg	Access-aggregation expressions.
com.espertech.esper.epl.expression.baseagg	Base aggregation expressions.
com.espertech.esper.epl.expression.core	Core expression classes.
com.espertech.esper.epl.expression.dot	Chained expression functionality.
com.espertech.esper.epl.expression.funcs	Function expressions.
com.espertech.esper.epl.expression.methodagg	Method-aggregation expressions.
com.espertech.esper.epl.expression.ops	Operator expressions.
com.espertech.esper.epl.expression.prev	'Previous'-group expressions.
com.espertech.esper.epl.expression.prior	'Prior'-group expressions.
com.espertech.esper.epl.expression.subquery	Subselect expressions.
com.espertech.esper.epl.expression.table	Table access and identifiers expressions.
com.espertech.esper.epl.expression.time	Time-related expressions.
com.espertech.esper.epl.script	Script expression evaluation.
com.espertech.esper.epl.spec	Contains EPL statement specification classes define the constructs that make up an EPL statement, such as the list of items in the select clause, the insert-into stream name and property names etc.
com.espertech.esper.filter	Main switchboard filtering and routing of incoming events to interested statements is performed in this package.
com.espertech.esper.pattern.guard	Pattern guards that can define the lifetime of a pattern
com.espertech.esper.pattern.observer	Pattern observer classes the observe timer events
com.espertech.esper.rowregex	Match-recognize expression tree and state objects.
com.espertech.esper.schedule	Package for timer callback scheduling
com.espertech.esper.type	Internal primitive, enum and other type representations
com.espertech.esper.util	Utility classes that center around Java type handling, printing, reflection, debugging

Uses of MetaDefItem in com.espertech.esper.client

Classes in com.espertech.esper.client that implement MetaDefItem

Modifier and Type	Class and Description
class	ConfigurationEventTypeAvro Configuration for Avro event types.
class	ConfigurationEventTypeMap Configuration object for Map-based event types.
class	ConfigurationEventTypeObjectArray Configuration object for Object array-based event types.
class	ConfigurationEventTypeWithSupertype Configuration object for event types with super-types and timestamp.
class	ConfigurationEventTypeXMLDOM Configuration object for enabling the engine to process events represented as XML DOM document nodes.

Uses of MetaDefItem in com.espertech.esper.client.soda

Classes in com.espertech.esper.client.soda that implement MetaDefItem

Modifier and Type	Class and Description
class	UpdateClause Specification for the update clause.

Uses of MetaDefItem in com.espertech.esper.collection

Classes in com.espertech.esper.collection that implement MetaDefItem

Modifier and Type	Class and Description
class	MultiKeyUntyped Functions as a key value for Maps where keys need to be composite values.
class	MultiKeyUntypedEventPair Functions as a key value for Maps where keys need to be composite values, and includes an EventBean handle The class allows a Map that uses MultiKeyUntyped entries for key values to use multiple objects as keys.
class	UniformPair<T> General-purpose pair of values of any type.

Uses of MetaDefItem in com.espertech.esper.core.service

Classes in com.espertech.esper.core.service that implement MetaDefItem

Modifier and Type	Class and Description
class	EPStatementHandle Class exists once per statement and hold statement resource lock(s).

Uses of MetaDefItem in com.espertech.esper.epl.declexpr

Subinterfaces of MetaDefItem in com.espertech.esper.epl.declexpr

Modifier and Type	Interface and Description
interface	ExprDeclaredNode Expression instance as declared elsewhere.

Classes in com.espertech.esper.epl.declexpr that implement MetaDefItem

Modifier and Type	Class and Description
class	ExprDeclaredNodeImpl Expression instance as declared elsewhere.

Uses of MetaDefItem in com.espertech.esper.epl.enummethod.dot

Classes in com.espertech.esper.epl.enummethod.dot that implement MetaDefItem

Modifier and Type	Class and Description
class	ExprLambdaGoesNode Represents the case-when-then-else control flow function is an expression tree.

Uses of MetaDefItem in com.espertech.esper.epl.expression.accessagg

Classes in com.espertech.esper.epl.expression.accessagg that implement MetaDefItem

Modifier and Type	Class and Description
class	ExprAggCountMinSketchNode Represents the Count-min sketch aggregate function.
class	ExprAggMultiFunctionLinearAccessNode
class	ExprAggMultiFunctionSortedMinMaxByNode
class	ExprPlugInAggMultiFunctionNode Represents a custom aggregation function in an expresson tree.

Uses of MetaDefItem in com.espertech.esper.epl.expression.baseagg

Subinterfaces of MetaDefItem in com.espertech.esper.epl.expression.baseagg

Modifier and Type	Interface and Description
interface	ExprAggregateNode Base expression node that represents an aggregation function such as 'sum' or 'count'.

Classes in com.espertech.esper.epl.expression.baseagg that implement MetaDefItem

Modifier and Type	Class and Description
class	ExprAggregateNodeBase Base expression node that represents an aggregation function such as 'sum' or 'count'.
class	ExprAggregateNodeGroupKey

Uses of MetaDefItem in com.espertech.esper.epl.expression.core

Subinterfaces of MetaDefItem in com.espertech.esper.epl.expression.core

Modifier and Type	Interface and Description
interface	ExprConstantNode Represents a constant in an expressiun tree.
interface	ExprIdentNode Represents an stream property identifier in a filter expressiun tree.
interface	ExprNode
interface	ExprStreamRefNode Represents a stream-reference.
interface	ExprStreamUnderlyingNode Represents an stream selector that returns the streams underlying event, or null if undefined.
interface	ExprVariableNode Represents a variable in an expression tree.

Classes in com.espertech.esper.epl.expression.core that implement MetaDefItem

Modifier and Type	Class and Description
class	ExprConstantNodeImpl Represents a constant in an expressiun tree.
class	ExprContextPropertyNodeImpl Represents an stream property identifier in a filter expressiun tree.
class	ExprCurrentEvaluationContextNode Represents the "current_evaluation_context" function in an expression tree.
class	ExprGroupingIdNode
class	ExprGroupingNode
class	ExprIdentNodeImpl Represents an stream property identifier in a filter expressiun tree.
class	ExprNamedParameterNodeImpl
class	ExprNodeBase Superclass for filter nodes in a filter expression tree.
class	ExprNodeValidated A placeholder for another expression node that has been validated already.
class	ExprNumberSetCronParam Expression for a parameter within a crontab.
class	ExprNumberSetFrequency Expression for use within crontab to specify a frequency.
class	ExprNumberSetList Expression for use within crontab to specify a list of values.
class	ExprNumberSetRange Expression for use within crontab to specify a range.
class	ExprOrderedExpr A placeholder expression for view/pattern object parameters that allow sorting expression values ascending or descending.
class	ExprStreamUnderlyingNodeImpl Represents an stream selector that returns the streams underlying event, or null if undefined.
class	ExprSubstitutionNode Represents a substitution value to be substituted in an expression tree, not valid for any purpose of use as an expression, however can take a place in an expression tree.
class	ExprTypedNoEvalNode Represents an expression node that returns the predefined type and that cannot be evaluated.
class	ExprVariableNodeImpl Represents a variable in an expression tree.
class	ExprWildcardImpl Expression for use within crontab to specify a wildcard.

Uses of MetaDefItem in com.espertech.esper.epl.expression.dot

Subinterfaces of MetaDefItem in com.espertech.esper.epl.expression.dot

Modifier and Type	Interface and Description
interface	ExprDotNode Represents an Dot-operator expression, for use when "(expression).method(...).method(...)"

Classes in com.espertech.esper.epl.expression.dot that implement MetaDefItem

Modifier and Type	Class and Description
class	ExprAppDotMethodImpl
class	ExprDotNodeImpl Represents an Dot-operator expression, for use when "(expression).method(...).method(...)"

Uses of MetaDefItem in com.espertech.esper.epl.expression.funcs

Classes in com.espertech.esper.epl.expression.funcs that implement MetaDefItem

Modifier and Type	Class and Description
class	ExprCaseNode Represents the case-when-then-else control flow function is an expression tree.
class	ExprCastNode Represents the CAST(expression, type) function is an expression tree.
class	ExprCoalesceNode Represents the COALESCE(a,b,...) function is an expression tree.
class	ExprInstanceofNode Represents the INSTANCEOF(a,b,...) function is an expression tree.
class	ExprIStreamNode Represents the RSTREAM() function in an expression tree.
class	ExprMinMaxRowNode Represents the MAX(a,b) and MIN(a,b) functions is an expression tree.
class	ExprPlugInSingleRowNode Represents an invocation of a plug-in single-row function in the expression tree.
class	ExprPropertyExistsNode Represents the EXISTS(property) function in an expression tree.
class	ExprTypeofNode Represents the TYPEOF(a) function is an expression tree.

Uses of MetaDefItem in com.espertech.esper.epl.expression.methodagg

Classes in com.espertech.esper.epl.expression.methodagg that implement MetaDefItem

Modifier and Type	Class and Description
class	ExprAvedevNode Represents the avedev(...) aggregate function is an expression tree.
class	ExprAvgNode Represents the avg(...) aggregate function is an expression tree.
class	ExprCountEverNode Represents the "countever" aggregate function is an expression tree.
class	ExprCountNode Represents the count(...) and count(*) and count(distinct ...) aggregate function is an expression tree.
class	ExprFirstEverNode Represents the "firstever" aggregate function is an expression tree.
class	ExprLastEverNode Represents the "lastever" aggregate function is an expression tree.
class	ExprLeavingAggNode Represents the leaving() aggregate function is an expression tree.
class	ExprMedianNode Represents the median(...) aggregate function is an expression tree.
class	ExprMinMaxAggrNode Represents the min/max(distinct? ...) aggregate function is an expression tree.
class	ExprNthAggNode Represents the nth(...) and aggregate function is an expression tree.
class	ExprPlugInAggNode Represents a custom aggregation function in an expresson tree.
class	ExprRateAggNode Represents the rate(...) and aggregate function is an expression tree.
class	ExprStddevNode Represents the stddev(...) aggregate function is an expression tree.
class	ExprSumNode Represents the sum(...) aggregate function is an expression tree.

Uses of MetaDefItem in com.espertech.esper.epl.expression.ops

Subinterfaces of MetaDefItem in com.espertech.esper.epl.expression.ops

Modifier and Type	Interface and Description
interface	ExprAndNode Represents an And-condition.
interface	ExprBetweenNode Represents the between-clause function in an expression tree.
interface	ExprEqualsNode Represents an equals (=, !=, <>, is, is not) comparator in a filter expressiun tree.
interface	ExprInNode Represents the in-clause (set check) function in an expression tree.
interface	ExprRelationalOpNode Represents a lesser or greater then (</<=/>/>=) expression in a filter expression tree.

Classes in com.espertech.esper.epl.expression.ops that implement MetaDefItem

Modifier and Type	Class and Description
class	ExprAndNodeImpl Represents an And-condition.
class	ExprArrayNode Represents an array in a filter expressiun tree.
class	ExprBetweenNodeImpl Represents the between-clause function in an expression tree.
class	ExprBitWiseNode Represents the bit-wise operators in an expression tree.
class	ExprConcatNode Represents a string concatenation.
class	ExprEqualsAllAnyNode Represents an equals-for-group (= ANY/ALL/SOME (expression list)) comparator in a expression tree.
class	ExprEqualsNodeImpl Represents an equals (=) comparator in a filter expressiun tree.
class	ExprInNodeImpl Represents the in-clause (set check) function in an expression tree.
class	ExprLikeNode Represents the like-clause in an expression tree.
class	ExprMathNode Represents a simple Math (+/-/divide/*) in a filter expression tree.
class	ExprNewInstanceNode Represents the "new Class(...)" operator in an expression tree.
class	ExprNewStructNode Represents the "new {...}" operator in an expression tree.
class	ExprNotNode Represents a NOT expression in an expression tree.
class	ExprOrNode Represents an OR expression in a filter expression tree.
class	ExprRegexpNode Represents the regexp-clause in an expression tree.
class	ExprRelationalOpAllAnyNode Represents a lesser or greater then (</<=/>/>=) expression in a filter expression tree.
class	ExprRelationalOpNodeImpl Represents a lesser or greater then (</<=/>/>=) expression in a filter expression tree.

Uses of MetaDefItem in com.espertech.esper.epl.expression.prev

Classes in com.espertech.esper.epl.expression.prev that implement MetaDefItem

Modifier and Type	Class and Description
class	ExprPreviousMatchRecognizeNode Represents the 'prev' previous event function in match-recognize "define" item.
class	ExprPreviousNode Represents the 'prev' previous event function in an expression node tree.

Uses of MetaDefItem in com.espertech.esper.epl.expression.prior

Classes in com.espertech.esper.epl.expression.prior that implement MetaDefItem

Modifier and Type	Class and Description
class	ExprPriorNode Represents the 'prior' prior event function in an expression node tree.

Uses of MetaDefItem in com.espertech.esper.epl.expression.subquery

Classes in com.espertech.esper.epl.expression.subquery that implement MetaDefItem

Modifier and Type	Class and Description
class	ExprSubselectAllSomeAnyNode Represents a subselect in an expression tree.
class	ExprSubselectExistsNode Represents an exists-subselect in an expression tree.
class	ExprSubselectInNode Represents a subselect in an expression tree.
class	ExprSubselectNode Represents a subselect in an expression tree.
class	ExprSubselectRowNode Represents a subselect in an expression tree.

Uses of MetaDefItem in com.espertech.esper.epl.expression.table

Classes in com.espertech.esper.epl.expression.table that implement MetaDefItem

Modifier and Type	Class and Description
class	ExprTableAccessNode
class	ExprTableAccessNodeKeys
class	ExprTableAccessNodeSubprop
class	ExprTableAccessNodeSubpropAccessor
class	ExprTableAccessNodeTopLevel
class	ExprTableIdentNode
class	ExprTableIdentNodeSubpropAccessor

Uses of MetaDefItem in com.espertech.esper.epl.expression.time

Subinterfaces of MetaDefItem in com.espertech.esper.epl.expression.time

Modifier and Type	Interface and Description
interface	ExprTimePeriod Expression representing a time period.

Classes in com.espertech.esper.epl.expression.time that implement MetaDefItem

Modifier and Type	Class and Description
class	ExprTimePeriodImpl Expression representing a time period.
class	ExprTimestampNode Represents the CURRENT_TIMESTAMP() function or reserved keyword in an expression tree.

Uses of MetaDefItem in com.espertech.esper.epl.script

Classes in com.espertech.esper.epl.script that implement MetaDefItem

Modifier and Type	Class and Description
class	ExprNodeScript

Uses of MetaDefItem in com.espertech.esper.epl.spec

Subinterfaces of MetaDefItem in com.espertech.esper.epl.spec

Modifier and Type	Interface and Description
interface	SelectClauseElementRaw Marker interface for elements in a select clause that is in the raw (storable) form.
interface	StreamSpec Specification for a stream, consists simply of an optional stream name and a list of views on to of the stream.
interface	StreamSpecCompiled Validated stream specifications generally have expression nodes that are valid and event types exist.
interface	StreamSpecRaw An uncompiled, unoptimize for of stream specification created by a parser.

Classes in com.espertech.esper.epl.spec that implement MetaDefItem

Modifier and Type	Class and Description
class	AnnotationDesc Describes an annotation.
class	ColumnDesc Describes a column name and type.
class	CreateIndexDesc Specification for creating a named window.
class	CreateIndexItem Specification for creating a named window index column.
class	CreateSchemaDesc Specification for creating an event type/schema.
class	CreateTableColumn
class	CreateTableDesc Descriptor for create-table statements.
class	CreateVariableDesc Descriptor for create-variable statements.
class	CreateWindowDesc Specification for creating a named window.
class	DBStatementStreamSpec Specification object for historical data poll via database SQL statement.
class	FilterSpecRaw Filter definition in an un-validated and un-resolved form.
class	FilterStreamSpecCompiled Specification for building an event stream out of a filter for events (supplying type and basic filter criteria) and views onto these events which are staggered onto each other to supply a final stream of events.
class	FilterStreamSpecRaw Unvalided filter-based stream specification.
class	ForClauseItemSpec
class	ForClauseSpec
class	InsertIntoDesc Descriptor generated by INSERT-INTO clauses specified in expressions to insert the results of statement as a stream to further statements.
class	MatchRecognizeDefineItem Specification for a "define" construct within a match_recognize.
class	MatchRecognizeInterval Interval specification within match_recognize.
class	MatchRecognizeMeasureItem Specification for measure definition item within match_recognize.
class	MatchRecognizeSkip Specification for the skip-part of match_recognize.
class	MatchRecognizeSpec Specification for match_recognize.
class	MethodStreamSpec Specification object for historical data poll via database SQL statement.
class	NamedWindowConsumerStreamSpec Specification for use of an existing named window.
class	ObjectSpec Encapsulates the information required to specify an object identification and construction.
class	OnTriggerDesc Specification for on-trigger statements.
class	OnTriggerMergeDesc Specification for the merge statement.
class	OnTriggerSetAssignment Descriptor for an on-set assignment.
class	OnTriggerSetDesc Specification for the on-set statement.
class	OnTriggerSplitStreamDesc Specification for the on-select splitstream statement.
class	OnTriggerWindowDesc Specification for the on-select and on-delete and on-update (via subclass) (no split-stream) statement.
class	OnTriggerWindowUpdateDesc Specification for the on-select and on-delete (no split-stream) statement.
class	OrderByItem Specification object to an element in the order-by expression.
class	OuterJoinDesc Contains the ON-clause criteria in an outer join.
class	OutputLimitSpec Spec for defining an output rate
class	PatternGuardSpec Specification for a pattern guard object consists of a namespace, name and guard object parameters.
class	PatternObserverSpec Specification for a pattern observer object consists of a namespace, name and object parameters.
class	PatternStreamSpecCompiled Specification for building an event stream out of a pattern statement and views staggered onto the pattern statement.
class	PatternStreamSpecRaw Pattern specification in unvalidated, unoptimized form.
class	PropertyEvalAtom Atom in a specification for property evaluation.
class	PropertyEvalSpec Specification for property evaluation.
class	RowLimitSpec Spec for defining a row limit.
class	SelectClauseElementWildcard Represents a wildcard as a select clause element.
class	SelectClauseExprRawSpec Represents a single item in a SELECT-clause, potentially unnamed as no "as" tag may have been supplied in the syntax.
class	SelectClauseSpecRaw Encapsulates the parsed select expressions in a select-clause in an EPL statement.
class	SelectClauseStreamRawSpec For use in select clauses for specifying a selected stream: select a.* from MyEvent as a, MyOther as b
class	StatementSpecRaw Specification object representing a complete EPL statement including all EPL constructs.
class	StreamSpecBase Abstract base specification for a stream, consists simply of an optional stream name and a list of views on to of the stream.
class	StreamSpecOptions Abstract base specification for a stream, consists simply of an optional stream name and a list of views on to of the stream.
class	TableQueryStreamSpec Specification for use of an existing table.
class	UpdateDesc Specification for the update statement.
class	ViewSpec Specification for a view object consists of a namespace, name and view object parameters.

Uses of MetaDefItem in com.espertech.esper.filter

Subinterfaces of MetaDefItem in com.espertech.esper.filter

Modifier and Type	Interface and Description
interface	FilterSpecParamFilterForEval
interface	FilterSpecParamFilterForEvalDouble
interface	FilterSpecParamInValue Denotes a value for use by the in-keyword within a list of values

Classes in com.espertech.esper.filter that implement MetaDefItem

Modifier and Type	Class and Description
class	DoubleRangeComparator Comparator for DoubleRange values.
class	FilterForEvalConstantAnyType Constant value in a list of values following an in-keyword.
class	FilterForEvalConstantDouble A Double-typed value as a filter parameter representing a range.
class	FilterForEvalConstantString A String-typed value as a filter parameter representing a range.
class	FilterForEvalContextPropDouble
class	FilterForEvalContextPropMayCoerce Event property value in a list of values following an in-keyword.
class	FilterForEvalContextPropString
class	FilterForEvalEventPropDouble An event property as a filter parameter representing a range.
class	FilterForEvalEventPropIndexedDouble An event property as a filter parameter representing a range.
class	FilterForEvalEventPropIndexedMayCoerce Event property value in a list of values following an in-keyword.
class	FilterForEvalEventPropMayCoerce Event property value in a list of values following an in-keyword.
class	FilterSpecLookupable
class	FilterSpecLookupableAdvancedIndex
class	FilterSpecParam This class represents one filter parameter in an FilterSpecCompiled filter specification.
class	FilterSpecParamAdvancedIndexQuadTreeMXCIF
class	FilterSpecParamAdvancedIndexQuadTreePointRegion
class	FilterSpecParamComparator Sort comparator for filter parameters that sorts filter parameters according to filter operator type.
class	FilterSpecParamConstant This class represents a single, constant value filter parameter in an FilterSpecCompiled filter specification.
class	FilterSpecParamContextProp This class represents a filter parameter containing a reference to a context property.
class	FilterSpecParamEventProp This class represents a filter parameter containing a reference to another event's property in the event pattern result, for use to describe a filter parameter in a FilterSpecCompiled filter specification.
class	FilterSpecParamEventPropIndexed This class represents a filter parameter containing a reference to another event's property in the event pattern result, for use to describe a filter parameter in a FilterSpecCompiled filter specification.
class	FilterSpecParamExprNode This class represents an arbitrary expression node returning a boolean value as a filter parameter in an FilterSpecCompiled filter specification.
class	FilterSpecParamIn This class represents a 'in' filter parameter in an FilterSpecCompiled filter specification.
class	FilterSpecParamRange This class represents a range filter parameter in an FilterSpecCompiled filter specification.

Uses of MetaDefItem in com.espertech.esper.pattern.guard

Classes in com.espertech.esper.pattern.guard that implement MetaDefItem

Modifier and Type	Class and Description
class	ExpressionGuardFactory Factory for TimerWithinGuard instances.
class	TimerWithinGuardFactory Factory for TimerWithinGuard instances.
class	TimerWithinOrMaxCountGuardFactory

Uses of MetaDefItem in com.espertech.esper.pattern.observer

Classes in com.espertech.esper.pattern.observer that implement MetaDefItem

Modifier and Type	Class and Description
class	TimerAtObserverFactory Factory for 'crontab' observers that indicate truth when a time point was reached.
class	TimerIntervalObserverFactory Factory for making observer instances.
class	TimerScheduleObserverFactory Factory for ISO8601 repeating interval observers that indicate truth when a time point was reached.

Uses of MetaDefItem in com.espertech.esper.rowregex

Classes in com.espertech.esper.rowregex that implement MetaDefItem

Modifier and Type	Class and Description
class	RowRegexExprNode Base node for
class	RowRegexExprNodeAlteration Or-condition in a regex expression tree.
class	RowRegexExprNodeAtom Atom in a regex expression tree.
class	RowRegexExprNodeConcatenation Concatenation of atoms in a regular expression tree.
class	RowRegexExprNodeNested Nested () regular expression in a regex expression tree.
class	RowRegexExprNodePermute Permute () regular expression in a regex expression tree.
class	RowRegexExprRepeatDesc

Uses of MetaDefItem in com.espertech.esper.schedule

Classes in com.espertech.esper.schedule that implement MetaDefItem

Modifier and Type	Class and Description
class	ScheduleSpec Holds a schedule specification which consists of a set of integer values or a null value for each schedule unit to indicate a wildcard.

Uses of MetaDefItem in com.espertech.esper.type

Subinterfaces of MetaDefItem in com.espertech.esper.type

Modifier and Type	Interface and Description
interface	NumberSetParameter Interface to generate a set of integers from parameters that include ranges, lists and frequencies.

Classes in com.espertech.esper.type that implement MetaDefItem

Modifier and Type	Class and Description
class	FrequencyParameter Encapsulates a parameter specifying a frequency, i.e.
class	IntParameter Parameter supplying a single int value is a set of numbers.
class	ListParameter Represents a list of values in a set of numeric parameters.
class	RangeParameter Represents a range of numbers as a parameter.
class	WildcardParameter Represents a wildcard as a parameter.

Uses of MetaDefItem in com.espertech.esper.util

Classes in com.espertech.esper.util that implement MetaDefItem

Modifier and Type	Class and Description
class	MultiKeyCastingComparator A comparator on multikeys.
class	MultiKeyCollatingComparator A comparator on multikeys with string values and using the Collator for comparing.
class	MultiKeyComparator A comparator on multikeys.
class	ObjectCollatingComparator A comparator on objects that takes a boolean array for ascending/descending.
class	ObjectComparator A comparator on objects that takes a boolean array for ascending/descending.