com.espertech.esper.filter

Class IndexHelper

java.lang.Object

com.espertech.esper.filter.IndexHelper

public class IndexHelper
extends Object

Utility class for matching filter parameters to indizes. Matches are indicated by the index FilterParamIndexBase and the filter parameter FilterSpecParam featuring the same event property name and filter operator.

Constructor Summary

Constructors

Constructor and Description
IndexHelper()

Method Summary

Modifier and Type	Method and Description
static Pair<FilterValueSetParam,FilterParamIndexBase>	findIndex(ArrayDeque<FilterValueSetParam> parameters, List<FilterParamIndexBase> indizes) Find an index that matches one of the filter parameters passed.
static FilterValueSetParam	findParameter(ArrayDeque<FilterValueSetParam> parameters, FilterParamIndexBase index) Determine among the passed in filter parameters any parameter that matches the given index on property name and filter operator type.

Methods inherited from class java.lang.Object

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

Constructor Detail

IndexHelper

public IndexHelper()

Method Detail

findIndex

public static Pair<FilterValueSetParam,FilterParamIndexBase> findIndex(ArrayDeque<FilterValueSetParam> parameters,
                                                                       List<FilterParamIndexBase> indizes)

Find an index that matches one of the filter parameters passed. The parameter type and index type match up if the property name and filter operator are the same for the index and the filter parameter. For instance, for a filter parameter of "count EQUALS 10", the index against property "count" with operator type EQUALS will be returned, if present. NOTE: The caller is expected to obtain locks, if necessary, on the collections passed in. NOTE: Doesn't match non-property based index - thus boolean expressions don't get found and are always entered as a new index

Parameters:

parameters - is the list of sorted filter parameters

indizes - is the collection of indexes

Returns:

A matching pair of filter parameter and index, if any matches were found. Null if no matches were found.

findParameter

public static FilterValueSetParam findParameter(ArrayDeque<FilterValueSetParam> parameters,
                                                FilterParamIndexBase index)

Determine among the passed in filter parameters any parameter that matches the given index on property name and filter operator type. Returns null if none of the parameters matches the index.

Parameters:

parameters - is the filter parameter list

index - is a filter parameter constant value index

Returns:

filter parameter, or null if no matching parameter found.