Class LimitFilter<T>

    • Constructor Detail

      • LimitFilter

        public LimitFilter()
        Default constructor (necessary for the ExternalizableLite interface).
      • LimitFilter

        public LimitFilter​(Filter<T> filter,
                           int cPageSize)
        Construct a limit filter.
        Parameters:
        filter - the filter whose results this Filter truncates
        cPageSize - the page size
    • 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 many keys will remain in the set after the index is applied. If no keys will remain in the set after the index is applied, this method should return 0. If all the keys will remain in the set, implying that no entries would be filtered out based on this filter, this method should return setKeys.size(). Otherwise, it should return the value between 0 and setKeys.size(). If there is no index in the specified index map that can be used by this filter, this method should return a negative integer.

        The effectiveness returned will be used by the composite filters to reorder nested filters from most to least effective, in order to optimize query execution.

        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 Filter whose results are truncated by this filter.
        Returns:
        the filter whose results are truncated by this filter
      • getPageSize

        public int getPageSize()
        Obtain the page size (expressed as a number of entries per page).
        Returns:
        the page size
      • setPageSize

        public void setPageSize​(int cPageSize)
        Set the page size (expressed as a number of entries per page).
        Parameters:
        cPageSize - the page size
      • getPage

        public int getPage()
        Obtain a current page number (zero-based).
        Returns:
        the page number
      • setPage

        public void setPage​(int nPage)
        Set the page number (zero-based). Setting the page number to zero will reset the filter's state.
        Parameters:
        nPage - the page number
      • getComparator

        public Comparator getComparator()
        Obtain the Comparator used to partition the entry values into pages.

        This method is intended to be used only by query processors. Clients should not modify the content of this property.

        Returns:
        the Comparator object
      • setComparator

        public void setComparator​(Comparator comparator)
        Set the Comparator used to partition the values into pages.

        This method is intended to be used only by query processors. Clients should not modify the content of this property.

        Parameters:
        comparator - Comparator object
      • getTopAnchor

        public Object getTopAnchor()
        Obtain the top anchor object, which is the last value object on a previous page.

        This method is intended to be used only by query processors. Clients should not modify the content of this property.

        Returns:
        top anchor object
      • setTopAnchor

        public void setTopAnchor​(Object oAnchor)
        Set the top anchor object.

        This method is intended to be used only by query processors. Clients should not modify the content of this property.

        Parameters:
        oAnchor - the top anchor object
      • getBottomAnchor

        public Object getBottomAnchor()
        Obtain the bottom anchor object, which is the last value object on the current page.

        This method is intended to be used only by query processors. Clients should not modify the content of this property.

        Returns:
        bottom anchor object
      • setBottomAnchor

        public void setBottomAnchor​(Object oAnchor)
        Set the bottom anchor object.

        This method is intended to be used only by query processors. Clients should not modify the content of this property.

        Parameters:
        oAnchor - the bottom anchor object
      • getCookie

        public Object getCookie()
        Obtain the cookie object.

        This method is intended to be used only by query processors. Clients should not modify the content of this property.

        Returns:
        cookie object
      • setCookie

        public void setCookie​(Object oCookie)
        Set the cookie object.

        This method is intended to be used only by query processors. Clients should not modify the content of this property.

        Parameters:
        oCookie - the cookie object
      • getBatchSize

        public int getBatchSize()
        Return the number of members query concurrently.
        Returns:
        batch size
      • setBatchSize

        public int setBatchSize​(int cBatch)
        Set the number of members query concurrently.
        Parameters:
        cBatch - batch size
        Returns:
        the set batch size
      • nextPage

        public void nextPage()
        Switch to the next page.
      • previousPage

        public void previousPage()
        Switch to the previous page.
      • extractPage

        public Object[] extractPage​(Object[] aEntry)
        Extract a subset of the specified array to fit the filter's parameters (i.e. page size and page number). If this filter has a comparator, the specified array is presumed to be sorted accordingly.

        The returned array is guaranteed to iterate exactly in the same order as the original array.

        Parameters:
        aEntry - an original array of entries
        Returns:
        an array of entries extracted accordingly to the filter parameters
      • extractPage

        public Set extractPage​(Set set)
        Extract a subset of the specified set to fit the filter's parameters (i.e. page size and page number). If this filter has a comparator, the specified Set is presumed to be sorted accordingly.

        The returned set is guaranteed to iterate exactly in the same order as the original set.

        Parameters:
        set - an original set of entries
        Returns:
        a set of entries extracted accordingly to the filter parameters
      • extractPage

        public Object[] extractPage​(Iterator iter)
        Extract a subset of the specified iterator to fit the filter's parameters (i.e. page size and page number). The returned array is guaranteed to iterate exactly in the same order as the original iterator.
        Parameters:
        iter - an original entry iterator
        Returns:
        an array of entries extracted accordingly to the filter parameters
      • toString

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

        public Object clone()
        Clone this filter.
        Overrides:
        clone in class Object
        Returns:
        a clone of this 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