HintEnum (Esper API Documentation)

java.lang.Object
- java.lang.Enum<HintEnum>
- - com.espertech.esper.client.annotation.HintEnum

All Implemented Interfaces:

Serializable, Comparable<HintEnum>
```
public enum HintEnum
extends Enum<HintEnum>
```
Enumeration of hint values. Since hints may be a comma-separate list in a single @Hint annotation they are listed as enumeration values here.

Enum Constant Summary

Enum Constants
Enum Constant and Description
`DISABLE_RECLAIM_GROUP` For use with group-by, disabled reclaim groups.
`DISABLE_UNIQUE_IMPLICIT_IDX` For use everywhere where unique data window are used
`DISABLE_WHEREEXPR_MOVETO_FILTER` For use everywhere where unique data window are used
`DISABLE_WINDOW_SUBQUERY_INDEXSHARE` If ENABLE_WINDOW_SUBQUERY_INDEXSHARE is not specified for a named window (the default) then this instruction is ignored.
`ENABLE_OUTPUTLIMIT_OPT` For use with output rate limiting to enable certain optimization that may however change output.
`ENABLE_WINDOW_SUBQUERY_INDEXSHARE` For use with create-named-window statements only, to indicate that statements that subquery the named window use named window data structures (unless the subquery statement specifies below DISBABLE hint and as listed below).
`EXCLUDE_PLAN` For use where query planning applies.
`FORCE_NESTED_ITER` For use with join query plans to force a nested iteration plan.
`INDEX` For use everywhere where indexes are used (subquery, joins, fire-and-forget, onl-select etc.), index hint.
`ITERATE_ONLY` For use with match_recognize, iterate-only matching.
`MAX_FILTER_WIDTH` For use when filter expression optimization may widen the filter expression.
`PREFER_MERGE_JOIN` For use with join query plans to indicate preferance of the merge-join query plan.
`RECLAIM_GROUP_AGED` For use with group-by and std:groupwin, reclaim groups for unbound streams based on time.
`RECLAIM_GROUP_FREQ` For use with group-by and std:groupwin, reclaim groups for unbound streams based on time, this number is the frequency in seconds at which a sweep occurs for aged groups, if not provided then the sweep frequency is the same number as the age.
`SET_NOINDEX` For use with subqueries and on-select, on-merge, on-update and on-delete to specify the query engine neither build an implicit index nor use an existing index, always performing a full table scan.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`Hint`	`getHint(Annotation[] annotations)` Check if the hint is present in the annotations provided.
`String`	`getHintAssignedValue(Hint annotation)` Returns hint value.
`List<String>`	`getHintAssignedValues(Annotation[] annotations)` Returns all values assigned for a given hint, if any
`String`	`getValue()` Returns the constant.
`boolean`	`isAcceptsParameters()` True if the hint accepts params.
`boolean`	`isRequiresParameters()` True if the hint requires params.
`static String[]`	`splitCommaUnlessInParen(String line)` Split a line of comma-separated values allowing parenthesis.
`static Map<HintEnum,List<String>>`	`validateGetListed(Annotation annotation)` Validate a hint annotation ensuring it contains only recognized hints.
`static HintEnum`	`valueOf(String name)` Returns the enum constant of this type with the specified name.
`static HintEnum[]`	`values()` Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum
clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object
getClass, notify, notifyAll, wait, wait, wait

- Enum Constant Detail
  - ITERATE_ONLY
```
public static final HintEnum ITERATE_ONLY
```
    For use with match_recognize, iterate-only matching.
  - DISABLE_RECLAIM_GROUP
```
public static final HintEnum DISABLE_RECLAIM_GROUP
```
    For use with group-by, disabled reclaim groups.
  - RECLAIM_GROUP_AGED
```
public static final HintEnum RECLAIM_GROUP_AGED
```
    For use with group-by and std:groupwin, reclaim groups for unbound streams based on time. The number of seconds after which a groups is reclaimed if inactive.
  - RECLAIM_GROUP_FREQ
```
public static final HintEnum RECLAIM_GROUP_FREQ
```
    For use with group-by and std:groupwin, reclaim groups for unbound streams based on time, this number is the frequency in seconds at which a sweep occurs for aged groups, if not provided then the sweep frequency is the same number as the age.
  - ENABLE_WINDOW_SUBQUERY_INDEXSHARE
```
public static final HintEnum ENABLE_WINDOW_SUBQUERY_INDEXSHARE
```
    For use with create-named-window statements only, to indicate that statements that subquery the named window use named window data structures (unless the subquery statement specifies below DISBABLE hint and as listed below).
    By default and if this hint is not specified or subqueries specify a stream filter on a named window, subqueries use statement-local data structures representing named window contents (table, index). Such data structure is maintained by consuming the named window insert and remove stream.
  - DISABLE_WINDOW_SUBQUERY_INDEXSHARE
```
public static final HintEnum DISABLE_WINDOW_SUBQUERY_INDEXSHARE
```
    If ENABLE_WINDOW_SUBQUERY_INDEXSHARE is not specified for a named window (the default) then this instruction is ignored.
    For use with statements that subquery a named window and that benefit from a statement-local data structure representing named window contents (table, index), maintained through consuming the named window insert and remove stream.
  - SET_NOINDEX
```
public static final HintEnum SET_NOINDEX
```
    For use with subqueries and on-select, on-merge, on-update and on-delete to specify the query engine neither build an implicit index nor use an existing index, always performing a full table scan.
  - FORCE_NESTED_ITER
```
public static final HintEnum FORCE_NESTED_ITER
```
    For use with join query plans to force a nested iteration plan.
  - PREFER_MERGE_JOIN
```
public static final HintEnum PREFER_MERGE_JOIN
```
    For use with join query plans to indicate preferance of the merge-join query plan.
  - INDEX
```
public static final HintEnum INDEX
```
    For use everywhere where indexes are used (subquery, joins, fire-and-forget, onl-select etc.), index hint.
  - EXCLUDE_PLAN
```
public static final HintEnum EXCLUDE_PLAN
```
    For use where query planning applies.
  - DISABLE_UNIQUE_IMPLICIT_IDX
```
public static final HintEnum DISABLE_UNIQUE_IMPLICIT_IDX
```
    For use everywhere where unique data window are used
  - MAX_FILTER_WIDTH
```
public static final HintEnum MAX_FILTER_WIDTH
```
    For use when filter expression optimization may widen the filter expression.
  - DISABLE_WHEREEXPR_MOVETO_FILTER
```
public static final HintEnum DISABLE_WHEREEXPR_MOVETO_FILTER
```
    For use everywhere where unique data window are used
  - ENABLE_OUTPUTLIMIT_OPT
```
public static final HintEnum ENABLE_OUTPUTLIMIT_OPT
```
    For use with output rate limiting to enable certain optimization that may however change output.
- Method Detail
  - values
```
public static HintEnum[] values()
```
    Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:
```
for (HintEnum c : HintEnum.values())
    System.out.println(c);
```
    Returns:
    
    an array containing the constants of this enum type, in the order they are declared
  - valueOf
```
public static HintEnum valueOf(String name)
```
    Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)
    
    Parameters:
    
    name - the name of the enum constant to be returned.
    
    Returns:
    
    the enum constant with the specified name
    
    Throws:
    
    IllegalArgumentException - if this enum type has no constant with the specified name
    
    NullPointerException - if the argument is null
  - getValue
```
public String getValue()
```
    Returns the constant.
    
    Returns:
    
    constant
  - isAcceptsParameters
```
public boolean isAcceptsParameters()
```
    True if the hint accepts params.
    
    Returns:
    
    indicator
  - isRequiresParameters
```
public boolean isRequiresParameters()
```
    True if the hint requires params.
    
    Returns:
    
    indicator
  - getHint
```
public Hint getHint(Annotation[] annotations)
```
    Check if the hint is present in the annotations provided.
    
    Parameters:
    
    annotations - the annotations to inspect
    
    Returns:
    
    indicator
  - validateGetListed
```
public static Map<HintEnum,List<String>> validateGetListed(Annotation annotation)
                                                    throws AnnotationException
```
    Validate a hint annotation ensuring it contains only recognized hints.
    
    Parameters:
    
    annotation - to validate
    
    Returns:
    
    validated hint enums and their parameter list
    
    Throws:
    
    AnnotationException - if an invalid text was found
  - getHintAssignedValue
```
public String getHintAssignedValue(Hint annotation)
```
    Returns hint value.
    
    Parameters:
    
    annotation - to look for
    
    Returns:
    
    hint assigned first value provided
  - getHintAssignedValues
```
public List<String> getHintAssignedValues(Annotation[] annotations)
```
    Returns all values assigned for a given hint, if any
    
    Parameters:
    
    annotations - to be interogated
    
    Returns:
    
    hint assigned values or null if none found
  - splitCommaUnlessInParen
```
public static String[] splitCommaUnlessInParen(String line)
```
    Split a line of comma-separated values allowing parenthesis.
    
    Parameters:
    
    line - to split
    
    Returns:
    
    parameters

Enum HintEnum

Enum Constant Summary

Method Summary

Methods inherited from class java.lang.Enum

Methods inherited from class java.lang.Object

Enum Constant Detail

ITERATE_ONLY

DISABLE_RECLAIM_GROUP

RECLAIM_GROUP_AGED

RECLAIM_GROUP_FREQ

ENABLE_WINDOW_SUBQUERY_INDEXSHARE

DISABLE_WINDOW_SUBQUERY_INDEXSHARE

SET_NOINDEX

FORCE_NESTED_ITER

PREFER_MERGE_JOIN

INDEX

EXCLUDE_PLAN

DISABLE_UNIQUE_IMPLICIT_IDX

MAX_FILTER_WIDTH

DISABLE_WHEREEXPR_MOVETO_FILTER

ENABLE_OUTPUTLIMIT_OPT

Method Detail

values

valueOf

getValue

isAcceptsParameters

isRequiresParameters

getHint

validateGetListed

getHintAssignedValue

getHintAssignedValues

splitCommaUnlessInParen