com.ibm.websphere.rsadapter
Class CloudscapeDataStoreHelper

java.lang.Object
  |
  +--com.ibm.websphere.rsadapter.GenericDataStoreHelper
        |
        +--com.ibm.websphere.rsadapter.CloudscapeDataStoreHelper
All Implemented Interfaces:
DataStoreHelper, java.io.Serializable
Direct Known Subclasses:
CloudscapeNetworkServerDataStoreHelper
public class CloudscapeDataStoreHelper
extends GenericDataStoreHelper
implements java.io.Serializable

CloudscapeDataStoreHelper is a DataStoreHelper implementation customized for the Cloudscape database. When mapping a SQLException, the SQLException mappings from the CloudscapeDataStoreHelper are searched first, and subsequently, if no match is found, the SQLException mappings from the GenericDataStoreHelper are searched. If you have additional requirements on Cloudscape consider subclassing this implementation.

SQLException mappings specific to the CloudscapeDataStoreHelper are the following:

Error CodeSQL StatePortableSQLException subclass
40000StaleConnectionException.class
45000StaleConnectionException.class
50000StaleConnectionException.class
23500DuplicateKeyException.class
23L01DuplicateKeyException.class

See Also:
Serialized Form

Field Summary
protected  java.util.HashMap db2jErrorMap
           
protected static com.ibm.ejs.ras.TraceComponent db2jTc
           
 
Fields inherited from class com.ibm.websphere.rsadapter.GenericDataStoreHelper
EOLN, genErrorMap, resBundle
 
Fields inherited from interface com.ibm.websphere.rsadapter.DataStoreHelper
CLOUDSCAPE_HELPER, CLOUDSCAPE_NETWORK_SERVER_HELPER, CONNECTJDBC_HELPER, CUSTOM_HELPER, DATADIRECT_HELPER, DB2_390_HELPER, DB2_390_LOCAL_HELPER, DB2_400_HELPER, DB2_HELPER, DB2_UNIVERSAL_HELPER, GENERIC_HELPER, INFORMIX_HELPER, MSSQL_HELPER, ORACLE_HELPER, POTENTIAL_DEADLOCK, POTENTIAL_LOST_UPDATE, SEQUELINK_HELPER, SYBASE_HELPER, SYBASE11_HELPER, TX_REPEATABLE_READ_FORUPDATE, TX_SERIALIZABLE_FORUPDATE, UPDATE_ON_READONLY, WSCONNECTJDBC_HELPER
 
Constructor Summary
CloudscapeDataStoreHelper(java.util.Properties props)
          This CloudscapeDataStoreHelper constructor creates a new CloudscapeDataStoreHelper based on the DataStoreHelper properties provided.
 
Method Summary
 void doStatementCleanup(java.sql.PreparedStatement stmt)
          This method cleans up a statement before the statement is returned to the statement cache.
 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 CloudscapeDataStoreHelper, GenericDataStoreHelper, and user-defined SQLException maps.
 int getIsolationLevel(com.ibm.websphere.appprofile.accessintent.AccessIntent aIntent)
          This method determines the transaction isolation level based on the specified AccessIntent.
 int getResultSetConcurrency(com.ibm.websphere.appprofile.accessintent.AccessIntent intent)
          This method determines the result set concurrency based on the specified AccessIntent.
 void setUserDefinedMap(java.util.Map newmap)
          This method configures a user-defined SQLException map that supersedes default SQLException mappings for the DataStoreHelper.
 java.lang.String showLockInfo(java.util.Properties props)
          This method returns lock information for Cloudscape.
 
Methods inherited from class com.ibm.websphere.rsadapter.GenericDataStoreHelper
calcPartitionNumber, doConnectionCleanup, doConnectionSetup, getLockType, getMetaData, getPrintWriter, getResultSetType, getXAExceptionContents, hasLostUpdateOrDeadLockOccurred, isBatchUpdateSupportedWithAccessIntent, isConnectionError, mapException, mapException, modifyXAFlag, processGenericCredentials, processSQL, processSQL
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

db2jTc

protected static final com.ibm.ejs.ras.TraceComponent db2jTc

db2jErrorMap

protected java.util.HashMap db2jErrorMap
Constructor Detail

CloudscapeDataStoreHelper

public CloudscapeDataStoreHelper(java.util.Properties props)
This CloudscapeDataStoreHelper constructor creates a new CloudscapeDataStoreHelper based on the DataStoreHelper properties provided. The properties parameter is provided only for future extensibility and is currently unused.

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
  • escapeProcessing
  • fetchDirection
  • maxFieldSize
  • maxRows
  • queryTimeout

CloudscapeDataStoreHelper resets all of the statement properties listed above except for the queryTimeout 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 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 CloudscapeDataStoreHelper, 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, com.ibm.websphere.ce.cm.PortableSQLException.

getIsolationLevel

public int getIsolationLevel(com.ibm.websphere.appprofile.accessintent.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 CloudscapeDataStoreHelper is Connection.TRANSACTION_REPEATABLE_READ.

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

  • If the concurrency_control AccessIntent.CONCURRENCY_CONTROL_OPTIMISTIC then a transaction isolation level of Connection.TRANSACTION_READ_COMMITTED is returned.

  • If the concurrency_control 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 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:
aIntent - 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(com.ibm.websphere.appprofile.accessintent.AccessIntent intent)
                            throws javax.resource.ResourceException
This method determines the result set concurrency based on the specified AccessIntent. CloudscapeDataStoreHelper always returns java.sql.ResultSet.CONCUR_READ_ONLY, as java.sql.ResultSet.CONCUR_READ_ONLY is the only result set concurrency value supported by Cloudscape.

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

showLockInfo

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

This method returns lock information for Cloudscape. The props parameter may include the following properties:

  1. user - a user name that has a DBA authority. If not specified, the default value is null.
  2. password - the password corresponding to the user name. If not specified, the default value is null.
  3. databaseName - the database name. If not specified, the default value is "c:/db2jdb"

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 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

 

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