Package com.tangosol.util

Class ForwardOnlyMapIndex

java.lang.Object
com.tangosol.util.ForwardOnlyMapIndex
All Implemented Interfaces:
MapIndex
public class ForwardOnlyMapIndex extends Object implements MapIndex
ForwardOnlyMapIndex is a MapIndex implementation that unlike the SimpleMapIndex maintains only a forward index and not the inverse index. As a result, the content of getIndexContents() is always empty, so this index cannot be used for querying by IndexAwareFilter, with its primary use as a deserialization optimization.
Since:
Coherence 12.1.3
Author:
gg/hr/jh 2014.03.07

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    protected final BackingMapContext
    f_ctx
    The context associated with this index.
    protected final ValueExtractor
    f_extractor
    ValueExtractor object that this MapIndex uses to extract an indexable property value from a [converted] value stored in the resource map.
    protected boolean
    f_fLazy
    The "lazy" flag.
    protected final Map
    f_mapForward
    Map that contains the index values (forward index).

    Fields inherited from interface com.tangosol.util.MapIndex

    NO_VALUE

  • Constructor Summary

    Constructors
    Constructor
    Description
    ForwardOnlyMapIndex(ValueExtractor extractor, BackingMapContext ctx, boolean fOnDemand)
    Construct an index for the given map.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    delete(Map.Entry entry)
    Update this index in response to a remove operation on a cache.
    protected void
    deleteInternal(Map.Entry entry)
    Update this index in response to a remove operation on a cache.
    boolean
    equals(Object o)
    Compares the specified object with this index for equality.
    Object
    get(Object oKey)
    Using the index information if possible, get the value associated with the specified key.
    Comparator
    getComparator()
    Get the Comparator used to sort the index.
    Map
    getIndexContents()
    Get the Map that contains the index contents.
    ValueExtractor
    getValueExtractor()
    Obtain the ValueExtractor object that the MapIndex uses to extract an indexable Object from a value stored in the indexed Map.
    int
    hashCode()
    Returns the hash code value for this MapIndex.
    void
    insert(Map.Entry entry)
    Update this index in response to a insert operation on a cache.
    protected Map
    instantiateForwardIndex()
    Instantiate the forward index.
    boolean
    isOrdered()
    Determine if the MapIndex orders the contents of the indexed information.
    boolean
    isPartial()
    Determine if indexed information for any entry in the indexed Map has been excluded from this index.
    String
    toString()
    Returns a string representation of this SimpleMapIndex.
    void
    update(Map.Entry entry)
    Update this index in response to an update operation on a cache.
    protected void
    updateInternal(Map.Entry entry)
    Update this index in response to an update operation on a cache.

    Methods inherited from class java.lang.Object

    clone, finalize, getClass, notify, notifyAll, wait, wait, wait

    Methods inherited from interface com.tangosol.util.MapIndex

    getUnits

  • Field Details

    • f_extractor

      protected final ValueExtractor f_extractor
      ValueExtractor object that this MapIndex uses to extract an indexable property value from a [converted] value stored in the resource map.

    • f_mapForward

      protected final Map f_mapForward
      Map that contains the index values (forward index). The keys of the Map are the keys to the map being indexed and the values are the extracted values. This map is used by the IndexAwareComparators to avoid a conversion and value extraction steps.

    • f_ctx

      protected final BackingMapContext f_ctx
      The context associated with this index.

    • f_fLazy

      protected boolean f_fLazy
      The "lazy" flag.

  • Constructor Details

    • ForwardOnlyMapIndex

      public ForwardOnlyMapIndex(ValueExtractor extractor, BackingMapContext ctx, boolean fOnDemand)
      Construct an index for the given map.
      Parameters:
      extractor - the ValueExtractor that is used to extract an indexed value from a resource map entry
      ctx - the context associated with the indexed cache
      fOnDemand - if true, the forward index will be created "on-demand" as the values are attempted to be accessed; otherwise the forward index is populated proactively

  • Method Details

    • getValueExtractor

      public ValueExtractor getValueExtractor()
      Obtain the ValueExtractor object that the MapIndex uses to extract an indexable Object from a value stored in the indexed Map. This property is never null.
      Specified by:
      getValueExtractor in interface MapIndex
      Returns:
      a ValueExtractor object, never null

    • isOrdered

      public boolean isOrdered()
      Determine if the MapIndex orders the contents of the indexed information. To determine in which way the contents are ordered, get the Comparator from the index contents SortedMap object.
      Specified by:
      isOrdered in interface MapIndex
      Returns:
      true if the index contents are ordered, false otherwise

    • isPartial

      public boolean isPartial()
      Determine if indexed information for any entry in the indexed Map has been excluded from this index. This information is used for IndexAwareFilter implementations to determine the most optimal way to apply the index.

      Note: Queries that use a partial index are allowed not to return entries that are not indexed even though they would match the corresponding filter were they evaluated during the full scan (if there were no index). However, it's not allowable for a query to return entries that do not match the corresponding filter, regardless of their presence in the index.

      Specified by:
      isPartial in interface MapIndex
      Returns:
      true if any entry of the indexed Map has been excluded from the index, false otherwise

    • getComparator

      public Comparator getComparator()
      Get the Comparator used to sort the index.
      Specified by:
      getComparator in interface MapIndex
      Returns:
      the comparator

    • getIndexContents

      public Map getIndexContents()
      Get the Map that contains the index contents.

      The keys of the Map are the return values from the ValueExtractor operating against the indexed Map's values, and for each key, the corresponding value stored in the Map is a Set of keys to the indexed Map.

      If the MapIndex is known to be ordered, then the returned Map object will be an instance of SortedMap. The SortedMap may or may not have a Comparator object associated with it; see SortedMap.comparator().

      A client should assume that the returned Map object is read-only and must not attempt to modify it.

      Specified by:
      getIndexContents in interface MapIndex
      Returns:
      a Map (or a SortedMap) of the index contents

    • get

      public Object get(Object oKey)
      Using the index information if possible, get the value associated with the specified key. This is expected to be more efficient than using the ValueExtractor against an object containing the value, because the index should already have the necessary information at hand.
      Specified by:
      get in interface MapIndex
      Parameters:
      oKey - the key that specifies the object to extract the value from
      Returns:
      the value that would be extracted by this MapIndex's ValueExtractor from the object specified by the passed key; NO_VALUE if the index does not have the necessary information

    • insert

      public void insert(Map.Entry entry)
      Update this index in response to a insert operation on a cache.
      Specified by:
      insert in interface MapIndex
      Parameters:
      entry - the entry representing the object being inserted

    • update

      public void update(Map.Entry entry)
      Update this index in response to an update operation on a cache.
      Specified by:
      update in interface MapIndex
      Parameters:
      entry - the entry representing the object being updated

    • delete

      public void delete(Map.Entry entry)
      Update this index in response to a remove operation on a cache.
      Specified by:
      delete in interface MapIndex
      Parameters:
      entry - the entry representing the object being removed

    • instantiateForwardIndex

      protected Map instantiateForwardIndex()
      Instantiate the forward index.
      Returns:
      the forward index

    • updateInternal

      protected void updateInternal(Map.Entry entry)
      Update this index in response to an update operation on a cache.
      Parameters:
      entry - the entry representing the object being updated

    • deleteInternal

      protected void deleteInternal(Map.Entry entry)
      Update this index in response to a remove operation on a cache.
      Parameters:
      entry - the entry representing the object being removed

    • toString

      public String toString()
      Returns a string representation of this SimpleMapIndex.
      Overrides:
      toString in class Object
      Returns:
      a String representation of this SimpleMapIndex

    • equals

      public boolean equals(Object o)
      Compares the specified object with this index for equality. Returns true if the given object is also a SimpleMapIndex and the two represent the same index.
      Overrides:
      equals in class Object
      Parameters:
      o - object to be compared for equality with this MapIndex
      Returns:
      true if the specified object is equal to this index

    • hashCode

      public int hashCode()
      Returns the hash code value for this MapIndex.
      Overrides:
      hashCode in class Object
      Returns:
      the hash code value for this MapIndex