Class DB2DataStoreHelper

  • All Implemented Interfaces:
    Direct Known Subclasses:
    DB2390DataStoreHelper, DB2AS400DataStoreHelper, DB2UniversalDataStoreHelper

    public class DB2DataStoreHelper
    extends GenericDataStoreHelper
    DB2DataStoreHelper is a DataStoreHelper implementation customized for the DB2 legacy CLI-based JDBC driver. When mapping a SQLException, the SQLException mappings from the DB2DataStoreHelper are searched first; subsequently, if no match is found, the SQLException mappings from the GenericDataStoreHelper are searched. If you have additional requirements on DB2, consider subclassing this implementation.
    Note: This class and its methods can not be called or referenced directly by user applications.

    SQLException mappings specific to the DB2DataStoreHelper are the following:

    Error CodeSQL StatePortableSQLException subclass
    • Field Detail

      • db2Tc

        protected static final db2Tc
    • 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.
        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
        doConnectionSetup in class GenericDataStoreHelper
        conn - the connection to set up.
        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
        doStatementCleanup in class GenericDataStoreHelper
        stmt - the PreparedStatement.
        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 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.

        findMappingClass in class GenericDataStoreHelper
        e - The SQLException for which to locate a subclass.
        The subclass matching the SQLException, or null if no match was found.
        See Also:
        SQLException, PortableSQLException
      • getIsolationLevel

        public int getIsolationLevel(AccessIntent aIntent)
                              throws javax.resource.ResourceException
        This method determines the transaction isolation level based on the specified AccessIntent. If the AccessIntent parameter is null, a default value is returned that is appropriate for the database backend. The default transaction isolation level for DB2DataStoreHelper is Connection.TRANSACTION_REPEATABLE_READ.

        In the case where an AccessIntent is specified, DB2DataStoreHelper computes the transaction isolation level as follows:

        • If the concurrency control is AccessIntent.CONCURRENCY_CONTROL_OPTIMISTIC, a transaction isolation level of Connection.TRANSACTION_READ_COMMITTED is returned.

        • If the concurrency control is AccessIntent.CONCURRENCY_CONTROL_PESSIMISTIC and the access type is AccessIntent.ACCESS_TYPE_READ, a transaction isolation level of Connection.TRANSACTION_REPEATABLE_READ is returned.

        • If the concurrency control is AccessIntent.CONCURRENCY_CONTROL_PESSIMISTIC and the access type is AccessIntent.ACCESS_TYPE_UPDATE, the transation isolation level is determined from the following table based on the pessimistic update lock hint.

          pessimistic update lock hint transaction isolation level
        Specified by:
        getIsolationLevel in interface DataStoreHelper
        getIsolationLevel in class GenericDataStoreHelper
        intent - An AccessIntent
        A transaction isolation level appropriate for the specified AccessIntent.
        javax.resource.ResourceException - If a transaction isolation level cannot be determined from the AccessIntent.
        See Also:
        AccessIntent, Connection
      • getResultSetConcurrency

        public int getResultSetConcurrency(AccessIntent intent)
                                    throws javax.resource.ResourceException
        This method determines the result set concurrency based on the specified AccessIntent. DB2DataStoreHelper always returns java.sql.ResultSet.CONCUR_READ_ONLY.
        Specified by:
        getResultSetConcurrency in interface DataStoreHelper
        getResultSetConcurrency in class GenericDataStoreHelper
        intent - An AccessIntent.
        A result set concurrency constant defined on java.sql.ResultSet.
        javax.resource.ResourceException - If a result set concurrency cannot be determined from the AccessIntent.
        See Also:
        AccessIntent, ResultSet
      • showLockInfo

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

        This method returns DB2 lock information needed for the RAS subsystem. 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".
        showLockInfo in class GenericDataStoreHelper
        props - properties containing information needed to connect to the database.
        the lock information.
        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 WebSphere 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. Invoke this method only from DataStoreHelper classes subclassing this class. Do not invoke this method directly from application code. Internal WebSphere code does not invoke this method.

        Example usage of the setUserDefinedMap method:

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

        User-defined exception mapping takes priority over all other exception mapping done by a DataStoreHelper. This differs from the WAS 4.0 DataSource model where mapping by Error Code always takes precedence over mapping by SQL State.

        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 WebSphere DataStoreHelper implementations map the exception to UserDefinedException, whereas the WAS 4.0 DataSource map the exception to DuplicateKeyException.

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

        Specified by:
        setUserDefinedMap in interface DataStoreHelper
        setUserDefinedMap in class GenericDataStoreHelper
        newmap - a mapping of SQLException SQL States and Error Codes to 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 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.
        See Also:
        SQLException, PortableSQLException
      • getPrintWriter

        public getPrintWriter()
        This method is used to obtain the to use for logging when database logging is enabled (for example: WAS.database=all=enabled). By default, null is returned and a instance created by WebSphere is used. You can override this method to return a different instance instead of the default.
        Specified by:
        getPrintWriter in interface DataStoreHelper
        getPrintWriter in class GenericDataStoreHelper
        WAS 5.0.1
      • isBatchUpdateSupportedWithAccessIntent

        public boolean isBatchUpdateSupportedWithAccessIntent(AccessIntent accessIntent)
        This method is used to determine if CMP Entity Beans can support batch updates with the given AccessIntent. There are some AccessIntents (for example, WebSphere Optimistic Concurrency Control intent) for which some databases are not always capable of determining the number of updated rows. This prevents CMP Entity Beans from supporting batch updates. In such cases, this method must return false. DB2DataStoreHelper returns false if the concurrency control of the AccessIntent is AccessIntent.CONCURRENCY_CONTROL_OPTIMISTIC, and otherwise returns true.
        Specified by:
        isBatchUpdateSupportedWithAccessIntent in interface DataStoreHelper
        isBatchUpdateSupportedWithAccessIntent in class GenericDataStoreHelper
        accessIntent - AccessIntent
        boolean true if batching is allowed with the given AccessIntent, otherwise false.
        WAS 5.0.2
        See Also:
      • getLockType

        public int getLockType(AccessIntent intent)

        This method returns a lock type constant based on the update hint value of the specified AccessIntent. The lock type is used by the persistence manager to determine which locking hints should be used on a SELECT statement.

        Specified by:
        getLockType in interface DataStoreHelper
        getLockType in class GenericDataStoreHelper
        intent - An AccessIntent
        the lock type constant. Valid values are defined in
        See Also:
        AccessIntent, WSInteractionSpec
      • 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. WebSphere uses this method to obtain trace information for XAExceptions to include in WebSphere trace.
        Specified by:
        getXAExceptionContents in interface DataStoreHelper
        getXAExceptionContents in class GenericDataStoreHelper
        xae - the XAException.
        detailed information about the XAException, for inclusion in a WebSphere trace.
        WAS 5.0.2
        See Also:
IBM WebSphere Application ServerTM
Release 9.0