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ArrayFilterCalculateEffectiveness Method

Oracle® Fusion Middleware .NET API Reference for Oracle Coherence
14c (14.1.1.0)
F23534-02
Given an IDictionary of available indexes, determine if this IIndexAwareFilter can use any of the indexes to assist in its processing, and if so, determine how effective the use of that index would be.

Namespace:  Tangosol.Util.Filter
Assembly:  Coherence (in Coherence.dll) Version: 14.1.1.14 (14.1.1.14)
Syntax
C#
Copy
public abstract int CalculateEffectiveness(
	IDictionary indexes,
	ICollection keys
)

Parameters

indexes
Type: System.CollectionsIDictionary
The available ICacheIndex objects keyed by the related IValueExtractor; read-only.
keys
Type: System.CollectionsICollection
The set of keys that will be filtered; read-only.

Return Value

Type: Int32
An effectiveness estimate of how well this filter can use the specified indexes to filter the specified keys.

Implements

IIndexAwareFilterCalculateEffectiveness(IDictionary, ICollection)
Remarks

The returned value is an effectiveness estimate of how well this filter can use the specified indexes to filter the specified keys. An operation that requires no more than a single access to the index content (i.e. Equals, NotEquals) has an effectiveness of one. Evaluation of a single entry is assumed to have an effectiveness that depends on the index implementation and is usually measured as a constant number of the single operations. This number is referred to as evaluation cost.

If the effectiveness of a filter evaluates to a number larger than the keys.size() then a user could avoid using the index and iterate through the keys calling Evaluate rather than ApplyIndex.

See Also