com.tangosol.util.filter
Class ContainsFilter

java.lang.Object
  com.tangosol.util.Base
      com.tangosol.util.BitHelper
          com.tangosol.util.ExternalizableHelper
              com.tangosol.util.filter.ExtractorFilter
                  com.tangosol.util.filter.ComparisonFilter
                      com.tangosol.util.filter.ContainsFilter

All Implemented Interfaces:

ExternalizableLite, PortableObject, Filter, EntryFilter, IndexAwareFilter, java.io.Serializable

public class ContainsFilter
extends ComparisonFilter
implements IndexAwareFilter

Filter which tests a Collection or Object array value returned from a method invocation for containment of a given value.

More formally, if the specified extractor returns a Collection, evaluate(o) is functionally equivalent to the following code:

 return ((Collection) extract(o)).contains(getValue());
 

If the specified method returns an Object array, evaluate(o) is functionally equivalent to the following code:

 return Collections.asList((Object[]) extract(o)).contains(getValue());
 

Author:

jh 2005.06.06

Field Summary

Fields inherited from class com.tangosol.util.filter.ComparisonFilter

m_oValue

Fields inherited from class com.tangosol.util.filter.ExtractorFilter

EVAL_COST, m_extractor

Constructor Summary

ContainsFilter()
Default constructor (necessary for the ExternalizableLite interface).

ContainsFilter(java.lang.String sMethod, java.lang.Object oValue)
Construct an ContainsFilter for testing containment of the given object.

ContainsFilter(ValueExtractor extractor, java.lang.Object oValue)
Construct an ContainsFilter for testing containment of the given object.

Method Summary

Filter	applyIndex(java.util.Map mapIndexes, java.util.Set setKeys) Filter remaining keys using a Map of available indexes.
int	calculateEffectiveness(java.util.Map mapIndexes, java.util.Set setKeys) Given a Map of available indexes, determine if this IndexAwareFilter can use any of the indexes to assist in its processing, and if so, determine how effective the use of that index would be.
protected boolean	evaluateExtracted(java.lang.Object oExtracted) Evaluate the specified extracted value.

Methods inherited from class com.tangosol.util.filter.ComparisonFilter

calculateIteratorEffectiveness, calculateMatchEffectiveness, calculateRangeEffectiveness, equals, getValue, hashCode, readExternal, readExternal, toString, writeExternal, writeExternal

Methods inherited from class com.tangosol.util.filter.ExtractorFilter

evaluate, evaluateEntry, extract, getValueExtractor

Methods inherited from class com.tangosol.util.BitHelper

countBits, countBits, countBits, indexOfLSB, indexOfLSB, indexOfLSB, indexOfMSB, indexOfMSB, indexOfMSB, toBitString, toBitString, toBitString

Methods inherited from interface com.tangosol.util.filter.EntryFilter

evaluateEntry

Methods inherited from interface com.tangosol.util.Filter

evaluate

Constructor Detail

ContainsFilter

public ContainsFilter()

Default constructor (necessary for the ExternalizableLite interface).

ContainsFilter

public ContainsFilter(ValueExtractor extractor,
                      java.lang.Object oValue)

Construct an ContainsFilter for testing containment of the given object.

Parameters:

extractor - the ValueExtractor used by this filter

oValue - the object that a Collection or Object array is tested to contain

ContainsFilter

public ContainsFilter(java.lang.String sMethod,
                      java.lang.Object oValue)

Construct an ContainsFilter for testing containment of the given object.

Parameters:

sMethod - the name of the method to invoke via reflection

oValue - the object that a Collection or Object array is tested to contain

Method Detail

evaluateExtracted

protected boolean evaluateExtracted(java.lang.Object oExtracted)

Evaluate the specified extracted value.

Specified by:

evaluateExtracted in class ExtractorFilter

Parameters:

oExtracted - an extracted value to evaluate

calculateEffectiveness

public int calculateEffectiveness(java.util.Map mapIndexes,
                                  java.util.Set setKeys)

Given a Map of available indexes, determine if this IndexAwareFilter can use any of the indexes to assist in its processing, and if so, determine how effective the use of that index would be.

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 keySet.size() * <evaluation cost> then a user could avoid using the index and iterate through the keySet calling evaluate rather then applyIndex.

Specified by:

calculateEffectiveness in interface IndexAwareFilter

Parameters:

mapIndexes - the available MapIndex objects keyed by the related ValueExtractor; read-only

setKeys - the set of keys that will be filtered; read-only

Returns:

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

applyIndex

public Filter applyIndex(java.util.Map mapIndexes,
                         java.util.Set setKeys)

Filter remaining keys using a Map of available indexes.

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 EntryFilter) 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.

Specified by:

applyIndex in interface IndexAwareFilter

Parameters:

mapIndexes - the available MapIndex objects keyed by the related ValueExtractor; read-only

setKeys - the mutable set of keys that remain to be filtered

Returns:

a Filter object (which may be an EntryFilter) that can be used to process the remaining keys, or null if no additional filter processing is necessary