Package com.j_spaces.kernel.list

Class ExternallyLockedStoredList<T>

java.lang.Object
com.j_spaces.kernel.list.ExternallyLockedStoredList<T>
All Implemented Interfaces:
IHashEntry<Object,IStoredList<T>>, ICollection<T>, IOrderedList<T>, IStoredList<T>, IObjectsList
public class ExternallyLockedStoredList<T> extends Object implements IStoredList<T>, IOrderedList<T>
no Lock version of StoredList locks should be external to this class scanning after establishing a starting position should be left lock free

  • Constructor Details

    • ExternallyLockedStoredList

      public ExternallyLockedStoredList(boolean Support_Random_Scans)

  • Method Details

    • size

      public int size()
      Description copied from interface: ICollection
      Returns the amount of elements in the StoredList.
      Specified by:
      size in interface ICollection<T>
      Returns:
      size of the StoredList
      See Also:

    • optimizeScanForSingleObject

      public boolean optimizeScanForSingleObject()
      return true if we can save iterator creation and get a single entry
      Specified by:
      optimizeScanForSingleObject in interface IStoredList<T>
      Returns:
      true if we can optimize

    • isEmpty

      public boolean isEmpty()
      Description copied from interface: ICollection
      Returns true if this list is empty, i.e. has no elements. [Tail] - [Head]
      Specified by:
      isEmpty in interface ICollection<T>
      Returns:
      true if list is empty; false otherwise.

    • getHead

      public IObjectInfo<T> getHead()
      get head of SL
      Specified by:
      getHead in interface IStoredList<T>
      Returns:
      the head of the list

    • getObjectFromHead

      public T getObjectFromHead()
      get object from head of SL
      Specified by:
      getObjectFromHead in interface IStoredList<T>
      Returns:
      the value of the head of the list

    • establishPos

      protected ExternallyLockedStoredList.StoredListIterator<T> establishPos(boolean random_scan, ExternallyLockedStoredList.StoredListIterator<T> res)

    • establishOrderedPos

      protected ExternallyLockedStoredList.StoredListIterator<T> establishOrderedPos(ExternallyLockedStoredList.ObjectInfo<T> OrderedScanPivot, boolean ascending, ExternallyLockedStoredList.StoredListIterator<T> res)

    • nextPos

      protected IStoredListIterator<T> nextPos(ExternallyLockedStoredList.StoredListIterator<T> slh)

    • add

      public IObjectInfo<T> add(T subject)
      store an element
      Specified by:
      add in interface ICollection<T>
      Parameters:
      subject - element to store.
      Returns:
      an information node representing the inserted element; null if StoredList has been invalidated.

    • addUnlocked

      public IObjectInfo<T> addUnlocked(T subject)
      store an element, while the SL is unlocked
      Specified by:
      addUnlocked in interface IStoredList<T>
      Parameters:
      subject - element to store.
      Returns:
      an information node representing the inserted element; null if StoredList has been invalidated.

    • storeBeforeCeiling

      public IObjectInfo<T> storeBeforeCeiling(IObjectInfo<T> theCeiling, T subject)
      given an ObjectInfo of an existing element, store a new element right "before" this one. Method used in OrderedIndex object when the MasterList reflects the order of elements- head is the largest, tail the smallest
      Specified by:
      storeBeforeCeiling in interface IOrderedList<T>
      Parameters:
      theCeiling - a ceiling to the new element (towards the head); when null, the ceiling will be the Head.
      subject - a new element, to be inserted before the ceiling (towards the tail)
      Returns:
      an information node representing the inserted element.

      Note: not relevant for random scans

    • getLargerInOrder

      public IObjectInfo<T> getLargerInOrder(IObjectInfo<T> ref)
      in an ordered SL, get the element larger than ref
      Specified by:
      getLargerInOrder in interface IOrderedList<T>
      Parameters:
      ref - a reference to an OI (element in the )
      Returns:
      the next largest element to ref (towards head)

    • getSmallerInOrder

      public IObjectInfo<T> getSmallerInOrder(IObjectInfo<T> ref)
      in an ordered SL, get the element smaller than ref
      Specified by:
      getSmallerInOrder in interface IOrderedList<T>
      Parameters:
      ref - a reference to an OI (element in the )
      Returns:
      the next smallest to ref (towards tail)

    • remove

      public void remove(IObjectInfo<T> oi)
      remove an element described by ObjectInfo
      Specified by:
      remove in interface IStoredList<T>
      Parameters:
      oi - an existing element between Tail and Head

    • removeUnlocked

      public void removeUnlocked(IObjectInfo<T> oi)
      remove an element described by ObjectInfo, while the SL is unlocked
      Specified by:
      removeUnlocked in interface IStoredList<T>
      Parameters:
      oi - an existing element between Tail and Head

    • removeByObject

      public boolean removeByObject(T obj)
      given an object scan the list, find it and remove it, returns true if found
      Specified by:
      removeByObject in interface ICollection<T>
      Parameters:
      obj - element to remove
      Returns:
      true if object was removed; false otherwise (if element wasn't found)

    • contains

      public boolean contains(T obj)
      is this object contained in the SL ?
      Specified by:
      contains in interface ICollection<T>
      Parameters:
      obj - the element to search for
      Returns:
      true if element exists in the StoredList; false otherwise.

    • invalidate

      public boolean invalidate()
      Sets an indication that this StoredList is invalid. if isEmpty() returns true, the indication is set; otherwise the indication remains false. Called by PersistentGC when scanning for empty StoredList that can be garbage collected.
      Specified by:
      invalidate in interface IStoredList<T>
      Returns:
      true if StoredList was set to invalid; false otherwise.

    • isInvalid

      protected boolean isInvalid()
      Returns:
      true if the list is invalid

    • dump

      public void dump(org.slf4j.Logger logger, String msg)
      Description copied from interface: IStoredList
      Dump list content, used for Debug.
      Specified by:
      dump in interface IStoredList<T>
      Parameters:
      logger - logger to use
      msg - message to add in log

    • establishListScan

      public ExternallyLockedStoredList.StoredListIterator<T> establishListScan(boolean random_scan)
      establish a scan position. if random scanning supported we select a random position
      Specified by:
      establishListScan in interface ICollection<T>
      Parameters:
      random_scan - true enable random scan; false start from head.
      Returns:
      a Holder for this scan. This Resource should be released if scan ended prematurely.

    • establishListOrderedScan

      public IStoredListIterator<T> establishListOrderedScan(IObjectInfo<T> OrderedScanPivot, boolean ascending)
      establish a scan position in one direction ascending (twrds head) or descending (towards tail). if random scanning supported starting at a predefined pos this API is used by the OrderedIndex masterList to establish an index scan
      Specified by:
      establishListOrderedScan in interface IOrderedList<T>
      Parameters:
      OrderedScanPivot - a pivot from which to start this scan. if null, pivot is Head (if ascending is true); Tail otherwise
      ascending - if true scan from pivot towards head; if false scan from pivot towards tail.
      Returns:
      returns a Holder of this scan. This Resource should be released if scan ended prematurely.

    • next

      public IStoredListIterator<T> next(IStoredListIterator<T> slh)
      get the next element in scan order
      Specified by:
      next in interface ICollection<T>
      Parameters:
      slh - Holder representing a pivot position.
      Returns:
      the next pivot position in this scan; null if reached end of scan.

    • freeSLHolder

      public void freeSLHolder(IStoredListIterator<T> slh)
      this method is called by outside scan that want to quit the scan and return the slholder to the factory
      Specified by:
      freeSLHolder in interface IStoredList<T>
      Parameters:
      slh - Holder resource to return to pool; can be null.

    • isMultiObjectCollection

      public boolean isMultiObjectCollection()
      Description copied from interface: ICollection
      is it an actual multi object container.
      Specified by:
      isMultiObjectCollection in interface ICollection<T>
      Returns:
      true if its an actual list; false otherwise

    • isIterator

      public boolean isIterator()
      Description copied from interface: IObjectsList
      is the list an iterator or basic list ?
      Specified by:
      isIterator in interface IObjectsList

    • getHashCode

      public int getHashCode(int id)
      Specified by:
      getHashCode in interface IHashEntry<Object,IStoredList<T>>

    • getKey

      public Object getKey(int id)
      Specified by:
      getKey in interface IHashEntry<Object,IStoredList<T>>

    • getValue

      public IStoredList<T> getValue(int id)
      Specified by:
      getValue in interface IHashEntry<Object,IStoredList<T>>

    • isNativeHashEntry

      public boolean isNativeHashEntry()
      Specified by:
      isNativeHashEntry in interface IHashEntry<Object,IStoredList<T>>
      Returns:
      true if this is a native hashmap entry