Class DB2DataStoreHelper

    • Constructor Detail

      • DB2DataStoreHelper

        public DB2DataStoreHelper​(java.util.Properties props)
        This DB2DataStoreHelper constructor creates a new DB2DataStoreHelper based on the DataStoreHelper properties provided. All implementations inheriting from a data store helper must supply this same list of properties to their super class by invoking the constructor of their super class with the list of properties.
        Parameters:
        props - DataStoreHelper properties.
    • Method Detail

      • doConnectionSetup

        public void doConnectionSetup​(java.sql.Connection conn)
                               throws java.sql.SQLException

        This method configures a connection before first use. This method is invoked only when a new connection to the database is created. It is not invoked when connections are reused from the connection pool.

        This class will set a variable db2ZOS to FALSE as default value. This method sets to TRUE if the backend system is zOS.

        GenericDataStoreHelper does not perform any connection setup.

        Specified by:
        doConnectionSetup in interface DataStoreHelper
        Overrides:
        doConnectionSetup in class GenericDataStoreHelper
        Parameters:
        conn - the connection to set up.
        Throws:
        java.sql.SQLException - if connection setup cannot be completed successfully.
      • doStatementCleanup

        public void doStatementCleanup​(java.sql.PreparedStatement stmt)
                                throws java.sql.SQLException

        This method cleans up a statement before the statement is returned to the statement cache. This method is called only for statements being cached. It is called when at least one of the following statement properties has changed,

        • cursorName
        • fetchDirection
        • maxFieldSize
        • maxRows
        • queryTimeout

        DB2DataStoreHelper resets all of the statement properties listed above except for the cursorName property.

        The following operations do not need to be included in the statement cleanup since they are automatically performed by WebSphere when caching statements:

        • setFetchSize(0)
        • clearParameters()
        • clearWarnings()

        A helper class implementing this method can choose to do additional cleanup for the statement. However, this must never include closing the statement, since the statement is intended to be cached.

        Specified by:
        doStatementCleanup in interface DataStoreHelper
        Overrides:
        doStatementCleanup in class GenericDataStoreHelper
        Parameters:
        stmt - the PreparedStatement.
        Throws:
        java.sql.SQLException - if an error occurs cleaning up the statement.
      • findMappingClass

        public final java.lang.Class findMappingClass​(java.sql.SQLException e)

        This method locates the com.ibm.websphere.ce.cm.PortableSQLException subclass corresponding to the specified SQLException, as defined by the DB2DataStoreHelper, GenericDataStoreHelper, and user-defined SQLException maps. Precedence and related details of SQLException mapping are described on the DataStoreHelper.setUserDefinedMap method.

        Overriding this method is one of three options you have for modifying SQLException mapping. The other two options are overriding the mapException method and invoking the setUserDefinedMap method to add a user-defined SQLException map.

        Overrides:
        findMappingClass in class GenericDataStoreHelper
        Parameters:
        e - The SQLException for which to locate a com.ibm.websphere.ce.cm.PortableSQLException subclass.
        Returns:
        The com.ibm.websphere.ce.cm.PortableSQLException subclass matching the SQLException, or null if no match was found.
        See Also:
        SQLException, PortableSQLException
      • getIsolationLevel

        public int getIsolationLevel​(AccessIntent intent)
                              throws javax.resource.ResourceException
        This method determines the transaction isolation level to use as default for the database backend. The default transaction isolation level for DB2DataStoreHelper is Connection.TRANSACTION_REPEATABLE_READ.
        Specified by:
        getIsolationLevel in interface DataStoreHelper
        Overrides:
        getIsolationLevel in class GenericDataStoreHelper
        Parameters:
        intent - always null in Liberty.
        Returns:
        A transaction isolation level appropriate for the specified database.
        Throws:
        javax.resource.ResourceException - If a transaction isolation level cannot be determined.
      • showLockInfo

        public final java.lang.String showLockInfo​(java.util.Properties props)
                                            throws java.lang.Exception

        This method returns DB2 lock information. It is unused in Liberty. The props parameter can include the following properties:

        1. db2Install - DB2 bin directory
        2. outputFile - the output file for storing the lock information. If this property is not specifed, no output is generated and null is returned.
        3. workingDir - a directory with write permission for the method caller where temporary files can be created. If this property is not specified, the current directory is used.
        4. databaseName - the DB2 database name for which to collect lock information. If this property is not specified, the value defaults to "SAMPLE".
        Overrides:
        showLockInfo in class GenericDataStoreHelper
        Parameters:
        props - properties containing information needed to connect to the database.
        Returns:
        the lock information.
        Throws:
        java.lang.Exception - if an error occurs while collecting the lock information.
      • setUserDefinedMap

        public final void setUserDefinedMap​(java.util.Map newmap)

        This method configures a user-defined SQLException map that supersedes default SQLException mappings for the DataStoreHelper. The DataStoreHelper implementations provided by the application server use SQLException maps to detect fatal connection errors, as well as other specific types of connection errors. A custom DataStoreHelper can alter the default mappings by invoking this method. Do not invoke this method from a custom DataStoreHelper if you also configure identifyException for a dataSource. When you configure identifyException, the application server invokes this method to overlay the default error mappings with the error mappings that are specified in the custom property. Do not invoke this method directly from application code.

        Example usage of the setUserDefinedMap method:

            public MyCustomDataStoreHelper()
            {
               ...
               java.util.HashMap MyErrorMap = new java.util.HashMap(2);
               myErrorMap.put(-801, MyDuplicateKeyException.class);
               myErrorMap.put(-1015, MyStaleConnectionException.class);
               setUserDefinedMap(myErrorMap);
               ...
            }
         

        User-defined exception mapping takes priority over all other exception mapping done by a DataStoreHelper.

        For example, assume the following exception mappings are defined:

         User-defined mappings
         SQL State  S1000: UserDefinedException
        
         Default mappings
         Error Code 23505: DuplicateKeyException
         SQL State  S1000: StaleConnectionException
         

        Given the above mappings, if a SQLException is received with SQL State S1000 and Error Code 23505, the DataStoreHelper implementations map the exception to UserDefinedException.

        Additionally, mapping done by the DataStoreHelpers does not include mapping by chained exceptions when no match is found for the original exception.

        Specified by:
        setUserDefinedMap in interface DataStoreHelper
        Overrides:
        setUserDefinedMap in class GenericDataStoreHelper
        Parameters:
        newmap - a mapping of SQLException SQL States and Error Codes to com.ibm.websphere.ce.cm.PortableSQLException subclasses. The key for the Map must be a String (representing the SQL State) or an Integer (representing the Error Code). The value for the Map must be a subclass of com.ibm.websphere.ce.cm.PortableSQLException. User-defined subclasses are permitted, but are required to declare a public constructor accepting a SQLException as the single parameter. You can also use Void.class for the value, in which case any existing mapping for the specified SQL State or Error Code is removed.
      • getPrintWriter

        public java.io.PrintWriter getPrintWriter()
        This method is used to obtain the java.io.PrintWriter to use for logging when database logging is enabled (for example: WAS.database=all=enabled). By default, null is returned and a java.io.PrintWriter instance created is used. You can override this method to return a different java.io.PrintWriter instance instead of the default.
        Specified by:
        getPrintWriter in interface DataStoreHelper
        Overrides:
        getPrintWriter in class GenericDataStoreHelper
        Returns:
        java.io.PrintWriter.
      • getXAExceptionContents

        public java.lang.String getXAExceptionContents​(javax.transaction.xa.XAException x)
        This method provides a plug-in point for providing meaningful logging information for an XAException. The information can include details of the original exception that caused the XAException, if applicable. This method is used to obtain trace information for XAExceptions to include in trace.
        Specified by:
        getXAExceptionContents in interface DataStoreHelper
        Overrides:
        getXAExceptionContents in class GenericDataStoreHelper
        Parameters:
        x - the XAException.
        Returns:
        detailed information about the XAException, for inclusion in trace.