com.ibm.websphere.rsadapter

Class DerbyDataStoreHelper

  • All Implemented Interfaces:
    DataStoreHelper
    Direct Known Subclasses:
    DerbyNetworkServerDataStoreHelper

    public class DerbyDataStoreHelper
extends GenericDataStoreHelper
    DerbyDataStoreHelper is a DataStoreHelper implementation customized for the Derby database. When mapping a SQLException, the SQLException mappings from the DerbyDataStoreHelper are searched first, and subsequently, if no match is found, the SQLException mappings from the GenericDataStoreHelper are searched. If you have additional requirements on Derby you should 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 DerbyDataStoreHelper are the following:

    Error CodeSQL StatePortableSQLException subclass
    40000StaleConnectionException.class
    45000StaleConnectionException.class
    50000StaleConnectionException.class
    23505DuplicateKeyException.class
    23500DuplicateKeyException.class
    23L01DuplicateKeyException.class
    XCL10StaleStatementException.class
    Note: SQLStates 23500 and 23L01 are only used in the Cloudscape 5.1.x.x release and are kept in the DerbyDataStoreHelper error map for backward compatibility. Derby does not use the 23500 and 23L01 SQLStates.

    • Field Detail

      • derbyTc

        protected static final com.ibm.ejs.ras.TraceComponent derbyTc

      • derbyErrorMap

        protected java.util.HashMap derbyErrorMap

    • Constructor Detail

      • DerbyDataStoreHelper

        public DerbyDataStoreHelper(java.util.Properties props)
        This DerbyDataStoreHelper constructor creates a new DerbyDataStoreHelper 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

      • 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 that will be cached. It is called only if at least one of the following statement properties has changed,

        • cursorName
        • fetchDirection
        • maxFieldSize
        • maxRows
        • queryTimeout

        DerbyDataStoreHelper resets all of the statement properties listed above.

        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 may choose to do additional cleanup for the statement. However, this should 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 DerbyDataStoreHelper, 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 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 DerbyDataStoreHelper is Connection.TRANSACTION_REPEATABLE_READ.

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

        • If the concurrency control is AccessIntent.CONCURRENCY_CONTROL_OPTIMISTIC then 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 then 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 then the transation isolation level is determined from the following table based on the pessimistic update lock hint.

          pessimistic update lock hint transaction isolation level
          AccessIntent.PESSIMISTIC_UPDATE_LOCK_HINT_NONE
          AccessIntent.PESSIMISTIC_UPDATE_LOCK_HINT_WEAKEST_LOCK_AT_LOAD          		 Connection.TRANSACTION_REPEATABLE_READ
          AccessIntent.PESSIMISTIC_UPDATE_LOCK_HINT_NOCOLLISION Connection.TRANSACTION_READ_COMMITTED
          AccessIntent.PESSIMISTIC_UPDATE_LOCK_HINT_EXCLUSIVE Connection.TRANSACTION_SERIALIZABLE
        Specified by:
        getIsolationLevel in interface DataStoreHelper
        Overrides:
        getIsolationLevel in class GenericDataStoreHelper
        Parameters:
        intent - An AccessIntent
        Returns:
        A transaction isolation level appropriate for the specified AccessIntent.
        Throws:
        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. DerbyDataStoreHelper always returns java.sql.ResultSet.CONCUR_READ_ONLY, as java.sql.ResultSet.CONCUR_READ_ONLY is the only result set concurrency value supported by Derby.
        Specified by:
        getResultSetConcurrency in interface DataStoreHelper
        Overrides:
        getResultSetConcurrency in class GenericDataStoreHelper
        Parameters:
        intent - An AccessIntent.
        Returns:
        A result set concurrency constant defined on java.sql.ResultSet.
        Throws:
        javax.resource.ResourceException - If a result set concurrency cannot be determined from the AccessIntent.
        See Also:
        AccessIntent, ResultSet

      • 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);
       setUserDefinedMap(myErrorMap);
       ...
    }

        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
        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. Void.class may also be used for the value, in which case any existing mapping for the specified SQL State or Error Code is removed.
        See Also:
        SQLException, PortableSQLException
IBM WebSphere Application ServerTM
Release 8.5