Class DB2DataStoreHelper

java.lang.Object
com.ibm.websphere.rsadapter.GenericDataStoreHelper
com.ibm.websphere.rsadapter.DB2DataStoreHelper
All Implemented Interfaces:
DataStoreHelper
Direct Known Subclasses:
DB2AS400DataStoreHelper, DB2UniversalDataStoreHelper

public class DB2DataStoreHelper extends GenericDataStoreHelper
  • Constructor Details

    • DB2DataStoreHelper

      public DB2DataStoreHelper(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 Details

    • doConnectionSetup

      public void doConnectionSetup(Connection conn) throws 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:
      SQLException - if connection setup cannot be completed successfully.
    • doStatementCleanup

      public void doStatementCleanup(PreparedStatement stmt) throws 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:
      SQLException - if an error occurs cleaning up the statement.
    • findMappingClass

      public final Class findMappingClass(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:
    • 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 String showLockInfo(Properties props) throws 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:
      Exception - if an error occurs while collecting the lock information.
    • setUserDefinedMap

      public final void setUserDefinedMap(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 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.
    • getLockType

      public int getLockType(AccessIntent intent)
      This method is unused in Liberty.
      Specified by:
      getLockType in interface DataStoreHelper
      Overrides:
      getLockType in class GenericDataStoreHelper
    • getXAExceptionContents

      public String getXAExceptionContents(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.