Package com.arjuna.ats.arjuna

Class StateManager

  • Direct Known Subclasses:
    AbstractRecord, BasicAction, Lock, LockManager, StateManagerWrapper
    public class StateManager
extends Object
    The root of the Arjuna class hierarchy. This class provides state management facilities than can be automatically used by other classes by inheritance.
    Since:
    JTS 1.0.
    Version:
    $Id: StateManager.java 2342 2006-03-30 13:06:17Z $
    Author:
    Mark Little (mark@arjuna.com)

    • Field Detail

      • modifyingActions

        protected Hashtable modifyingActions

      • usingActions

        protected Hashtable usingActions

      • objectUid

        protected final Uid objectUid

      • objectModel

        protected int objectModel

    • Constructor Detail

      • StateManager

        protected StateManager​(Uid objUid)
        Create object with specific uid. This constructor is primarily used when recreating an existing object. The object type is set to 'ANDPERSISTENT' this is equivalent to invoking persist in the object constructor.

      • StateManager

        protected StateManager​(Uid objUid,
                       int ot)

      • StateManager

        protected StateManager​(Uid objUid,
                       int ot,
                       int om)

      • StateManager

        protected StateManager()

      • StateManager

        protected StateManager​(int ot)

      • StateManager

        protected StateManager​(int ot,
                       int om)

    • Method Detail

      • save_state

        public boolean save_state​(OutputObjectState os,
                          int ot)
        These methods must be used by a derived class. They are responsible for packing and unpacking an object's state to/from a state buffer. StateManager calls them at appropriate times during the lifetime of the object, and may then pass the buffer to a persistent object store for saving. If a derived class calls super.save_state then it must be called before packing any other data item.
        Returns:
        true on success, false otherwise.

      • restore_state

        public boolean restore_state​(InputObjectState os,
                             int ot)
        These methods must be provided by a derived class. They are responsible for packing and unpacking an object's state to/from a state buffer. StateManager calls them at appropriate times during the lifetime of the object, and may then pass the buffer to a persistent object store for saving. Data items must be unpacked in the same order that they were packed.
        Returns:
        true on success, false otherwise.

      • activate

        public boolean activate()
        This operation activates an object. Activation of an object may entail loading its passive state from the object store and unpacking it into the memory resident form, or it may simply be a no-op. Full activation is only necessary if the object is currently marked as being PASSIVE (that is, the object was constructed as being of type ANDPERSISTENT with an existing uid and has not already been activated). Objects that are not of type ANDPERSISTENT or are persistent but have not yet been saved in an object store (so-called new persistent objects) are unaffected by this function. Returns false if PASSIVE object cannot be loaded from object store, true otherwise. The root of the object store is taken as null.
        Returns:
        true on success, false otherwise.
        See Also:
        ObjectStore

      • activate

        public boolean activate​(String rootName)
        This operation activates an object. Activation of an object may entail loading its passive state from the object store and unpacking it into the memory resident form, or it may simply be a no-op. Full activation is only necessary if the object is currently marked as being PASSIVE (that is, the object was constructed as being of type ANDPERSISTENT with an existing uid and has not already been activated). Objects that are not of type ANDPERSISTENT or are persistent but have not yet been saved in an object store (so-called new persistent objects) are unaffected by this function. Returns false if PASSIVE object cannot be loaded from object store, true otherwise.
        Returns:
        true on success, false otherwise.
        See Also:
        ObjectStore

      • deactivate

        public boolean deactivate()
        This operation deactivates a persistent object. It behaves in a similar manner to the activate operation, but has an extra argument which defines whether the object's state should be committed or written as a shadow. The root of the object store is null. It is assumed that this is being called during a transaction commit.
        Returns:
        true on success, false otherwise.

      • deactivate

        public boolean deactivate​(String rootName)
        This operation deactivates a persistent object. It behaves in a similar manner to the activate operation, but has an extra argument which defines whether the object's state should be commited now or not. It is assumed that this is being called during a transaction commit.
        Returns:
        true on success, false otherwise.

      • deactivate

        public boolean deactivate​(String rootName,
                          boolean commit)
        This operation deactivates a persistent object. It behaves in a similar manner to the activate operation, but has an extra argument which defines whether the object's state should be commited now or not.
        Returns:
        true on success, false otherwise.

      • status

        public int status()
        Returns:
        the object's current status (active, passive, ...)

      • objectType

        public int objectType()
        Returns:
        the type of the object (persistent, recoverable, ...)

      • getObjectModel

        public int getObjectModel()

      • get_uid

        public final Uid get_uid()
        Returns:
        the object's unique identifier.

      • destroy

        public boolean destroy()
        Destroy the object (e.g., remove its state from the persistent store.) Calls to destroy for volatile objects (ones not maintained within the volatile object store) are ignored, and FALSE is returned.
        Returns:
        true on success, false otherwise.

      • disable

        public void disable()
        The following function disables recovery for an object by setting the ObjectType to NEITHER (RECOVERABLE or ANDPERSISTENT). The value of this variable is checked in the modified operation so that no recovery information is created if myType is set to NEITHER.

      • print

        public void print​(PrintWriter strm)
        Print out information about the object.

      • type

        public String type()
        The object's type. Derived classes should override this to reflect their type structure. Typically this string is used for locating the object state in an object store, and reflects the hierarchy structure of the object.

      • getStoreRoot

        public final String getStoreRoot()
        Returns:
        the root of the object store this instance will use if it has to save the state of the object to storage.

      • getStore

        public ParticipantStore getStore()
        Returns:
        the object store this instance will used if it has to save the state of the object to storage.

      • packHeader

        protected void packHeader​(OutputObjectState os,
                          com.arjuna.ats.internal.arjuna.Header hdr)
                   throws IOException
        Pack the necessary information for crash recovery.
        Throws:
        IOException
        Since:
        JTS 2.1.

      • unpackHeader

        protected void unpackHeader​(InputObjectState os,
                            com.arjuna.ats.internal.arjuna.Header hdr)
                     throws IOException
        Unpack the crash recovery state header information and return it.
        Parameters:
        os - the identity of the transaction that last caused the state to be written to the object store.
        Throws:
        IOException
        Since:
        JTS 2.1.

      • terminate

        protected void terminate()
        The following function checks to see if the object is going out of scope while an action is still running.

      • setStatus

        protected final void setStatus​(int s)

      • modified

        protected boolean modified()
        The object's state is about to be modified, and StateManager should take a snapshot of the state if the object is being used within a transaction.
        Returns:
        true on success, false otherwise.

      • persist

        protected final void persist()
        The persist function changes the type of the object from RECOVERABLE to ANDPERSISTENT. No changes are made unless the status of the object is ACTIVE, so it is not possible to change the type of the object if it has been modified.

      • cleanup

        protected final void cleanup​(boolean fromTerminate)
        Object cleanup. Attempt sane cleanup when object is deleted. Handle perverse cases where multiple actions are still active as object dies.
        Parameters:
        fromTerminate - indicates whether this method is being called from the terminate method, or from elsewhere.
        See Also:
        terminate()

      • setupStore

        protected final void setupStore()
        Make sure the object store is set up, if required. The root of the object store is assumed to be null.

      • setupStore

        protected void setupStore​(String rootName)

      • setupStore

        protected void setupStore​(String rootName,
                          String objectStoreType)
        Make sure the object store is set up, if required.
        Parameters:
        rootName - indicates the root of the object store.

      • loadObjectState

        protected final boolean loadObjectState()
        Do we need to load the object's state?
        Returns:
        true if the object state should be loaded, false otherwise.

      • forgetAction

        protected final boolean forgetAction​(BasicAction action,
                                     boolean committed,
                                     int recordType)
        Remove action from list of using actions. If the action list empties reset state to PASSIVE. The second param tells why the action should be forgotten. This aids in resetting the state correctly.

      • rememberAction

        protected final boolean rememberAction​(BasicAction action,
                                       int recordType,
                                       int state)
        Remember that the specified transaction is using the object.

      • getMutex

        protected final ReentrantLock getMutex()
        Returns:
        the mutex object used to lock this object.
        Since:
        JTS 2.1.

      • lockMutex

        protected final boolean lockMutex()
        Returns:
        the result of the attempt to lock this object.
        Since:
        JTS 2.1.

      • unlockMutex

        protected final boolean unlockMutex()
        Returns:
        the result of the attempt to unlock this object.
        Since:
        JTS 2.1.

      • tryLockMutex

        protected final boolean tryLockMutex()
        Returns:
        true if the object was locked, false if the attempt would cause the thread to block.
        Since:
        JTS 2.1.

      • createLists

        protected void createLists()