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Oracle® Coherence Java API Reference Release 12.1.2.0.3 E26043-02 |
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java.lang.Object
com.tangosol.util.Base
com.tangosol.util.BitHelper
com.tangosol.util.ExternalizableHelper
com.tangosol.util.filter.AbstractQueryRecorderFilter
com.tangosol.util.filter.ExtractorFilter
public abstract class ExtractorFilter
Base Filter implementation for doing extractor-based processing.
Field Summary | |
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static int |
EVAL_COST The evaluation cost as a factor to the single index access operation. |
protected ValueExtractor |
m_extractor The ValueExtractor used by this filter. |
Constructor Summary | |
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ExtractorFilter() Default constructor (necessary for the ExternalizableLite interface). |
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ExtractorFilter(java.lang.String sMethod) Construct an ExtractorFilter for a given method name. |
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ExtractorFilter(ValueExtractor extractor) Construct a ExtractorFilter for a given ValueExtractor. |
Method Summary | |
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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. |
static int |
calculateIteratorEffectiveness(int cKeys) Helper method to calculate effectiveness (or rather ineffectiveness) of a simple iteration against a key set that has to be performed due to an absence of corresponding index. |
boolean |
evaluate(java.lang.Object oTarget) Apply the test to the object. |
boolean |
evaluateEntry(java.util.Map.Entry entry) Apply the test to a Map Entry. |
protected abstract boolean |
evaluateExtracted(java.lang.Object oExtracted) Evaluate the specified extracted value. |
protected java.lang.Object |
extract(java.lang.Object o) Get the result of ValueExtractor invocation. |
ValueExtractor |
getValueExtractor() Obtain the ValueExtractor used by this filter. |
void |
readExternal(java.io.DataInput in) Restore the contents of this object by loading the object's state from the passed DataInput object. |
void |
readExternal(PofReader in) Restore the contents of a user type instance by reading its state using the specified PofReader object. |
void |
writeExternal(java.io.DataOutput out) Save the contents of this object by storing the object's state into the passed DataOutput object. |
void |
writeExternal(PofWriter out) Save the contents of a POF user type instance by writing its state using the specified PofWriter object. |
Methods inherited from class com.tangosol.util.filter.AbstractQueryRecorderFilter |
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explain, explain, explain, trace, trace, trace, trace, trace |
Methods inherited from class com.tangosol.util.BitHelper |
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countBits, countBits, countBits, indexOfLSB, indexOfLSB, indexOfLSB, indexOfMSB, indexOfMSB, indexOfMSB, rotateLeft, rotateLeft, rotateLeft, rotateRight, rotateRight, rotateRight, toBitString, toBitString, toBitString |
Field Detail |
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public static int EVAL_COST
IndexAwareFilter.calculateEffectiveness(Map, Set)
protected ValueExtractor m_extractor
Constructor Detail |
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public ExtractorFilter()
public ExtractorFilter(ValueExtractor extractor)
extractor
- the ValueExtractor to use by this filterpublic ExtractorFilter(java.lang.String sMethod)
sMethod
- a method name to make a ReflectionExtractor
for; this parameter can also be a dot-delimited sequence of method names which would result in an ExtractorFilter based on the ChainedExtractor
that is based on an array of corresponding ReflectionExtractor objectsMethod Detail |
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public boolean evaluate(java.lang.Object oTarget)
evaluate
in interface Filter
oTarget
- the object to testpublic boolean evaluateEntry(java.util.Map.Entry entry)
evaluateEntry
in interface EntryFilter
entry
- the Map Entry to evaluate; never nullprotected abstract boolean evaluateExtracted(java.lang.Object oExtracted)
oExtracted
- an extracted value to evaluateprotected java.lang.Object extract(java.lang.Object o)
o
- the object on which to invoke the ValueExtractor; must not be nullWrapperException
- if this ValueExtractor encounters an exception in the course of extracting the valuepublic ValueExtractor getValueExtractor()
public int calculateEffectiveness(java.util.Map mapIndexes, java.util.Set setKeys)
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.
calculateEffectiveness
in interface IndexAwareFilter
mapIndexes
- the available MapIndex
objects keyed by the related ValueExtractor; read-onlysetKeys
- the set of keys that will be filtered; read-onlypublic Filter applyIndex(java.util.Map mapIndexes, java.util.Set setKeys)
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.
applyIndex
in interface IndexAwareFilter
mapIndexes
- the available MapIndex
objects keyed by the related ValueExtractor; read-onlysetKeys
- the mutable set of keys that remain to be filteredFilter
object (which may be an EntryFilter
) that can be used to process the remaining keys, or null if no additional filter processing is necessarypublic static int calculateIteratorEffectiveness(int cKeys)
cKeys
- the number of keys to iterate throughpublic void readExternal(java.io.DataInput in) throws java.io.IOException
readExternal
in interface ExternalizableLite
in
- the DataInput stream to read data from in order to restore the state of this objectjava.io.IOException
- if an I/O exception occursjava.io.NotActiveException
- if the object is not in its initial state, and therefore cannot be deserialized intopublic void writeExternal(java.io.DataOutput out) throws java.io.IOException
writeExternal
in interface ExternalizableLite
out
- the DataOutput stream to write the state of this object tojava.io.IOException
- if an I/O exception occurspublic void readExternal(PofReader in) throws java.io.IOException
readExternal
in interface PortableObject
in
- the PofReader from which to read the object's statejava.io.IOException
- if an I/O error occurspublic void writeExternal(PofWriter out) throws java.io.IOException
writeExternal
in interface PortableObject
out
- the PofWriter to which to write the object's statejava.io.IOException
- if an I/O error occurs
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Oracle® Coherence Java API Reference Release 12.1.2.0.3 E26043-02 |
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