Interface IIndexAwareFilter

IIndexAwareFilter is an extension to the EntryFilter interface that allows a filter to use a cache index to fully or partially evaluate itself.

Inherited Members
Namespace: Tangosol.Util.Filter
Assembly: Coherence.dll
Syntax
public interface IIndexAwareFilter : IEntryFilter, IFilter

Methods

ApplyIndex(IDictionary, ICollection)

Filter remaining keys using an IDictionary of available indexes.

Declaration
IFilter ApplyIndex(IDictionary indexes, ICollection keys)
Parameters
Type Name Description
IDictionary indexes

The available ICacheIndex objects keyed by the related IValueExtractor; read-only.
ICollection keys

The mutable set of keys that remain to be filtered.
Returns
Type Description
IFilter

An IFilter object that can be used to process the remaining keys, or null if no additional filter processing is necessary.
Remarks

The filter is responsible for removing all keys from the passed set of keys that the applicable indexes can prove should be filtered. If the filter does not fully evaluate the remaining keys using just the index information, it must return a filter (which may be an IEntryFilter) that can complete the task using an iterating implementation. If, on the other hand, the filter does fully evaluate the remaining keys using just the index information, then it should return null to indicate that no further filtering is necessary.

CalculateEffectiveness(IDictionary, ICollection)

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.

Declaration
int CalculateEffectiveness(IDictionary indexes, ICollection keys)
Parameters
Type Name Description
IDictionary indexes

The available ICacheIndex objects keyed by the related IValueExtractor; read-only.
ICollection keys

The set of keys that will be filtered; read-only.
Returns
Type Description
int

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