Package com.tangosol.util.filter

Class PresentFilter<T>

    • Field Detail

      • INSTANCE

        public static final PresentFilter INSTANCE
        An instance of the PresentFilter.

    • Constructor Detail

      • PresentFilter

        public PresentFilter()
        Construct a PresentFilter.

    • Method Detail

      • 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

      • equals

        public boolean equals​(Object o)
        Compare the PresentFilter with another object to determine equality.
        Overrides:
        equals in class Object
        Returns:
        true iff this PresentFilter and the passed object are equivalent PresentFilters

      • hashCode

        public int hashCode()
        Determine a hash value for the PresentFilter object according to the general Object.hashCode() contract.
        Overrides:
        hashCode in class Object
        Returns:
        an integer hash value for this PresentFilter object

      • 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
        NotActiveException - if the object is not in its initial state, and therefore cannot be deserialized into

      • 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

      • INSTANCE

        public static <T> PresentFilter<T> INSTANCE()
        Return an instance of the PresentFilter.
        Type Parameters:
        T - the type of the input argument to the filter
        Returns:
        a PresentFilter instance