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com.tangosol.util.filter
Class XorFilter

java.lang.Object
com.tangosol.util.Base
com.tangosol.util.BitHelper
com.tangosol.util.ExternalizableHelper
com.tangosol.util.filter.ArrayFilter
com.tangosol.util.filter.XorFilter

All Implemented Interfaces:

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

public class XorFilter

extends ArrayFilter

Filter which returns the logical exclusive or ("xor") of two other filters.

Author:

cp/gg 2002.10.27

Nested Class Summary

Nested classes/interfaces inherited from class com.tangosol.util.filter.ArrayFilter

ArrayFilter.WeightedFilter

Field Summary

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

m_aFilter

Constructor Summary

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

XorFilter(Filter filterLeft, Filter filterRight)
Construct a "xor" filter.

Method Summary

protected Filter	applyIndex(java.util.Map mapIndexes, java.util.Set setKeys, QueryContext ctx, QueryRecord.PartialResult.TraceStep step) Apply the specified IndexAwareFilter to the specified keySet.
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.
boolean	evaluate(java.lang.Object o) Apply the test to the object.
protected boolean	evaluateEntry(java.util.Map.Entry entry, QueryContext context, QueryRecord.PartialResult.TraceStep step) Check if the given entry passes the filter's evaluation.

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

applyFilter, applyIndex, calculateFilters, equals, evaluateEntry, evaluateFilter, explain, getFilters, hashCode, readExternal, readExternal, toString, trace, trace, writeExternal, writeExternal

Methods inherited from class com.tangosol.util.BitHelper

countBits, countBits, countBits, indexOfLSB, indexOfLSB, indexOfLSB, indexOfMSB, indexOfMSB, indexOfMSB, rotateLeft, rotateLeft, rotateLeft, rotateRight, rotateRight, rotateRight, toBitString, toBitString, toBitString, toBytes, toBytes, toBytes, toBytes, toInt, toInt, toLong, toLong

Constructor Detail

XorFilter

public XorFilter()

Default constructor (necessary for the ExternalizableLite interface).

XorFilter

public XorFilter(Filter filterLeft,
                 Filter filterRight)

Construct a "xor" filter. The result is defined as:

filterLeft ^ filterRight

Parameters:

filterLeft - the "left" filter

filterRight - the "right" filter

Method Detail

evaluate

public boolean evaluate(java.lang.Object o)

Apply the test to the object.

Parameters:

o - the object to test

Returns:

true if the test passes, false otherwise

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.

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

protected Filter applyIndex(java.util.Map mapIndexes,
                            java.util.Set setKeys,
                            QueryContext ctx,
                            QueryRecord.PartialResult.TraceStep step)

Apply the specified IndexAwareFilter to the specified keySet. Record the actual cost of execution for each of the participating filters if a query context is provided.

Specified by:

applyIndex in class ArrayFilter

Parameters:

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

setKeys - the set of keys that would be filtered

ctx - the query ctx; may be null

step - the step used to record the execution cost

Returns:

a Filter object that can be used to process the remaining keys, or null if no additional filter processing is necessary

evaluateEntry

protected boolean evaluateEntry(java.util.Map.Entry entry,
                                QueryContext context,
                                QueryRecord.PartialResult.TraceStep step)

Check if the given entry passes the filter's evaluation. Record the actual cost of execution for each of the participating filters if a query context is provided.

Specified by:

evaluateEntry in class ArrayFilter

Parameters:

entry - a key value pair to filter

context - the query ctx; may be null

step - the step used to record the execution cost

Returns:

true if the entry passes the filter, false otherwise

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