Package com.tangosol.util.filter

Class InKeySetFilter<T>

java.lang.Object
com.tangosol.util.Base
com.tangosol.util.BitHelper
com.tangosol.util.ExternalizableHelper
com.tangosol.util.filter.AbstractQueryRecorderFilter<T>
com.tangosol.util.filter.InKeySetFilter<T>
All Implemented Interfaces:
ExternalizableLite, PortableObject, Filter<T>, EntryFilter<Object,T>, IndexAwareFilter<Object,T>, QueryRecorderFilter<T>, Serializable
public class InKeySetFilter<T> extends AbstractQueryRecorderFilter<T> implements EntryFilter<Object,T>, IndexAwareFilter<Object,T>, ExternalizableLite, PortableObject
Filter that limits the underlying filter evaluation only to the specified set of keys.

When used in the context of NamedMap.addMapListener, InKeySetFilter is used as a vessel to portray an intent to listen to the provided set of keys, and as such, should not be wrapped by another filter. InKeySetFilter should also not be used as the view filter for a ContinuousQueryCache or a View Cache. For these use cases, equivalent functionality is possible by using an InFilter with a KeyExtractor.

For example: 

 new InKeySetFilter(Filters.equal(Person::getLastName, "Rabbit"), setKeys)
or 
 Filters.equal(Person::getLastName, "Rabbit").forKeys(setKeys);
can be converted to: 
 Filters.in(ValueExtractor.identity().fromKey(), setKeys).and(Filters.equal(Person::getLastName, "Rabbit"))
Author:
gg 2006.06.12
See Also:

  • Constructor Details

    • InKeySetFilter

      public InKeySetFilter()
      Default constructor (necessary for the ExternalizableLite interface).

    • InKeySetFilter

      public InKeySetFilter(Filter<T> filter, Set<K> setKeys)
      Construct an InFilter for testing "In" condition.
      Type Parameters:
      K - the key type
      Parameters:
      filter - the underlying filter
      setKeys - the set of keys to limit the filter evaluation to

  • Method Details

    • evaluate

      public boolean evaluate(T o)
      Apply the test to the input argument.
      Specified by:
      evaluate in interface Filter<T>
      Parameters:
      o - the input argument to evaluate
      Returns:
      true if the input argument matches the filter, otherwise false

    • evaluateEntry

      public boolean evaluateEntry(Map.Entry entry)
      Apply the test to a Map Entry.
      Specified by:
      evaluateEntry in interface EntryFilter<Object,T>
      Parameters:
      entry - the Map Entry to evaluate; never null
      Returns:
      true if the test passes, false otherwise

    • calculateEffectiveness

      public int calculateEffectiveness(Map mapIndexes, 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<Object,T>
      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(Map mapIndexes, 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<Object,T>
      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

    • getFilter

      public Filter<T> getFilter()
      Obtain the underlying Filter.
      Returns:
      the underlying filter

    • getKeys

      public Set<?> getKeys()
      Obtain the underlying key set.
      Returns:
      the underlying key set

    • ensureConverted

      public void ensureConverted(Converter converter)
      Ensure that the underlying keys are converted using the specified converter.

      This method must be called prior to index application or evaluation when the keys being evaluated exist in an internal form.

      Note: for convenience, this method will be automatically called by the partitioned cache service when this filter appears as the outermost filter in a query.

      Parameters:
      converter - the converter that should be used for key conversions

    • ensureUnconverted

      public void ensureUnconverted(Converter converter)
      Ensure that the underlying keys are un-converted using the specified converter.
      Parameters:
      converter - the converter that should be used for key un-conversions
      Since:
      Coherence 12.2.1.1.0

    • isConverted

      public boolean isConverted()
      Check if the underlying key set has been converted.
      Returns:
      true if the underlying key has been converted
      Since:
      Coherence 12.2.1.1.0

    • markConverted

      public void markConverted()
      Mark the underlying keys set as converted.
      Since:
      Coherence 12.2.1.1.0

    • toString

      public String toString()
      Return a human-readable description for this Filter.
      Overrides:
      toString in class Object
      Returns:
      a String description of the Filter

    • readExternal

      public void readExternal(DataInput in) throws IOException
      Restore the contents of this object by loading the object's state from the passed DataInput object.
      Specified by:
      readExternal in interface ExternalizableLite
      Parameters:
      in - the DataInput stream to read data from in order to restore the state of this object
      Throws:
      IOException - if an I/O exception occurs

    • writeExternal

      public void writeExternal(DataOutput out) throws IOException
      Save the contents of this object by storing the object's state into the passed DataOutput object.
      Specified by:
      writeExternal in interface ExternalizableLite
      Parameters:
      out - the DataOutput stream to write the state of this object to
      Throws:
      IOException - if an I/O exception occurs

    • readExternal

      public void readExternal(PofReader in) throws IOException
      Restore the contents of a user type instance by reading its state using the specified PofReader object.
      Specified by:
      readExternal in interface PortableObject
      Parameters:
      in - the PofReader from which to read the object's state
      Throws:
      IOException - if an I/O error occurs

    • writeExternal

      public void writeExternal(PofWriter out) throws IOException
      Save the contents of a POF user type instance by writing its state using the specified PofWriter object.
      Specified by:
      writeExternal in interface PortableObject
      Parameters:
      out - the PofWriter to which to write the object's state
      Throws:
      IOException - if an I/O error occurs