Package com.ibm.di.queue

Class MemBufferQ

  • public class MemBufferQ
extends java.lang.Object
    A FIFO queue

    • Constructor Summary

      Constructors 
      Constructor Description
      MemBufferQ​(int nEntries)
      Deprecated.
      MemBufferQ​(int nEntries, int pagesize)
      Constructor Initializes the memory buffer pipe when paging is enabled.
      MemBufferQ​(int nEntries, int pagesize, boolean doNotInitialiseDB)
      Constructor Initializes the memory buffer pipe when paging is enabled.Initialization of the DB properties is done only when the queue is being created from the UserFunctions.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void acquireLock()  
      void blockAdd​(boolean enable)
      Enable disable blocking add this is used only when paging support is disabled.
      void enablePersistence​(boolean enable)
      enablePersistence : enable/disable paging support using system store
      DBHandler getDbHandler()  
      int getPercentMemoryUse()  
      void initDB​(java.lang.String sDBName, java.lang.String jdbcLogin, java.lang.String jdbcPassword, java.lang.String sTblName)
      Initializes the system store paramemters.
      boolean isEmpty()  
      boolean isMemoryAvailable()
      Checks if there is enough memory available as specified by the user
      boolean isPurging()  
      java.lang.Object peek()
      Same as read but does not remove data from the memq
      void purgeQueue()
      Purges the queue.
      java.lang.Object read()
      synchronized method: The first item inserted in the queue and not yet removed.
      java.lang.Object read​(int timeout)
      synchronized method: The first item inserted in the queue and not yet removed.
      void releaseLock()  
      void setDbHandler​(DBHandler dbHandler)  
      void setPercentMemoryUse​(int percentMemoryUse)  
      int size()  
      void terminate​(boolean dropSystemStore)
      terminates the system store threads and drops table if dropSystemStore set to true
      void write​(java.lang.Object x)
      write : add an object to the end of memq

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Constructor Detail

      • MemBufferQ

        public MemBufferQ​(int nEntries,
                  int pagesize)
           throws java.lang.Exception
        Constructor Initializes the memory buffer pipe when paging is enabled.
        Throws:
        java.lang.Exception

      • MemBufferQ

        public MemBufferQ​(int nEntries,
                  int pagesize,
                  boolean doNotInitialiseDB)
           throws java.lang.Exception
        Constructor Initializes the memory buffer pipe when paging is enabled.Initialization of the DB properties is done only when the queue is being created from the UserFunctions. For queues being created from the MemQueue Connector or FC , the DB table name is required to be specified by the user.
        Throws:
        java.lang.Exception

      • MemBufferQ

        @Deprecated
public MemBufferQ​(int nEntries)
        Deprecated.
        Constructor Initializes the memory buffer pipe when paging is disabled

    • Method Detail

      • initDB

        public void initDB​(java.lang.String sDBName,
                   java.lang.String jdbcLogin,
                   java.lang.String jdbcPassword,
                   java.lang.String sTblName)
            throws java.lang.Exception
        Initializes the system store paramemters.
        Parameters:
        sDBName - system store database name
        jdbcLogin - username to connect to the db
        jdbcPassword - password to connect to the db
        sTblName - table name
        Throws:
        java.lang.Exception - if system store is not initialized properly

      • isEmpty

        public boolean isEmpty()
        Returns:
        True if memQ is empty

      • size

        public int size()
        Returns:
        Number of items in the memq.

      • read

        public java.lang.Object read()
                      throws java.lang.Exception
        synchronized method: The first item inserted in the queue and not yet removed. Requires !isEmpty (). Reading removes the item from the queue. read with no timeout.
        Throws:
        java.lang.Exception

      • read

        public java.lang.Object read​(int timeout)
                      throws java.lang.Exception
        synchronized method: The first item inserted in the queue and not yet removed. Requires !isEmpty (). Reading removes the item from the queue. Waits for timeout
        Throws:
        java.lang.Exception

      • acquireLock

        public void acquireLock()
                 throws java.lang.InterruptedException
        Throws:
        java.lang.InterruptedException

      • releaseLock

        public void releaseLock()

      • write

        public void write​(java.lang.Object x)
           throws java.lang.Exception
        write : add an object to the end of memq
        Parameters:
        x - object to be added
        Throws:
        java.lang.Exception - if add fails

      • peek

        public java.lang.Object peek()
        Same as read but does not remove data from the memq
        Returns:
        object read

      • enablePersistence

        public void enablePersistence​(boolean enable)
        enablePersistence : enable/disable paging support using system store
        Parameters:
        enable - paging support enabled if true and disabled if false

      • isPurging

        public boolean isPurging()
        Returns:
        isBeingPurged Returns if purging is enabled/disabled.

      • blockAdd

        public void blockAdd​(boolean enable)
        Enable disable blocking add this is used only when paging support is disabled.
        Parameters:
        enable - if true, add to memq blocks infinitely until there is space for an object to be added to memq if false, add throws an exception if memq is full

      • terminate

        public void terminate​(boolean dropSystemStore)
        terminates the system store threads and drops table if dropSystemStore set to true
        Parameters:
        dropSystemStore -

      • purgeQueue

        public void purgeQueue()
                throws java.lang.Exception
        Purges the queue. The isBeingPurged Flag is set which blocks all reader or writer threads until the purge operation is not completed. Deletes all data from the associated table in System Store if this queue has paging enabled.
        Throws:
        java.lang.Exception

      • getPercentMemoryUse

        public int getPercentMemoryUse()

      • setPercentMemoryUse

        public void setPercentMemoryUse​(int percentMemoryUse)

      • isMemoryAvailable

        public boolean isMemoryAvailable()
        Checks if there is enough memory available as specified by the user

      • getDbHandler

        public DBHandler getDbHandler()

      • setDbHandler

        public void setDbHandler​(DBHandler dbHandler)