Class KeyFilter

EntryFilter which checks whether an entry key belongs to a set.

Inheritance
object
KeyFilter
Implements
Inherited Members
Namespace: Tangosol.Util.Filter
Assembly: Coherence.dll
Syntax
public class KeyFilter : IIndexAwareFilter, IEntryFilter, IFilter
Remarks

Note: this filter is not serializable and intended to be used only internally by other composite filters to reduce the remaining key set. As of Coherence 3.2, an equivalent functionality could be achieved using the InFilter as follows:

  new InFilter(new KeyExtractor(IdentityExtractor.INSTANCE), setKeys);

Constructors

KeyFilter(ICollection)

Construct a key filter.

Declaration
public KeyFilter(ICollection keys)
Parameters
Type Name Description
ICollection keys

The keys that this filter will evaluate to true.

Methods

ApplyIndex(IDictionary, ICollection)

Filter remaining keys using an IDictionary of available indexes.

Declaration
public 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
public 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.

Evaluate(object)

Apply the test to the object.

Declaration
public virtual bool Evaluate(object o)
Parameters
Type Name Description
object o

An object to which the test is applied.
Returns
Type Description
bool

true if the test passes, false otherwise.

EvaluateEntry(ICacheEntry)

Apply the test to an ICacheEntry.

Declaration
public bool EvaluateEntry(ICacheEntry entry)
Parameters
Type Name Description
ICacheEntry entry

The ICacheEntry to evaluate; never null.
Returns
Type Description
bool

true if the test passes, false otherwise.

ToString()

Return a human-readable description for this KeyAssociatedFilter.

Declaration
public override string ToString()
Returns
Type Description
string

A string description of the KeyFilter.
Overrides

Implements