DB2DataStoreHelper (IBM WebSphere Application Server [adapter])

com.ibm.websphere.rsadapter
Class DB2DataStoreHelper
java.lang.Object
  |
  +--com.ibm.websphere.rsadapter.GenericDataStoreHelper
        |
        +--com.ibm.websphere.rsadapter.DB2DataStoreHelper
All Implemented Interfaces:
DataStoreHelper, java.io.Serializable

Direct Known Subclasses:
DB2390DataStoreHelper, DB2AS400DataStoreHelper, DB2UniversalDataStoreHelper

public class DB2DataStoreHelper
extends GenericDataStoreHelper
implements java.io.Serializable

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, and 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.
SQLException mappings specific to the DB2DataStoreHelper are the following:

Error Code SQL State PortableSQLException subclass

-30081 StaleConnectionException.class

-6036 StaleConnectionException.class

-1229 StaleConnectionException.class

-1224 StaleConnectionException.class

-1035 StaleConnectionException.class

-1034 StaleConnectionException.class

-1015 StaleConnectionException.class

-803 DuplicateKeyException.class

-518 StaleConnectionException.class

-514 StaleConnectionException.class

58004 StaleConnectionException.class

S1000 Void.class

See Also:
Serialized Form

Field Summary

protected static com.ibm.ejs.ras.TraceComponent db2Tc


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

DB2DataStoreHelper(java.util.Properties props)
          This DB2DataStoreHelper constructor creates a new DB2DataStoreHelper based on the DataStoreHelper properties provided.

Method Summary

void doConnectionSetup(java.sql.Connection conn)
          This method configures a connection before first use.

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 DB2DataStoreHelper, 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 getLockType(com.ibm.websphere.appprofile.accessintent.AccessIntent intent)
          This method returns a locktype based on the input AccessIntent update hint value.

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).

int getResultSetConcurrency(com.ibm.websphere.appprofile.accessintent.AccessIntent intent)
          This method determines the result set concurrency based on the specified AccessIntent.

boolean isBatchUpdateSupportedWithAccessIntent(com.ibm.websphere.appprofile.accessintent.AccessIntent accessIntent)
          This method is used to determine if CMP Entity Beans can support batch updates with the given 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 DB2 lock information needed for the RAS subsystem.

Methods inherited from class com.ibm.websphere.rsadapter.GenericDataStoreHelper

calcPartitionNumber, doConnectionCleanup, getMetaData, getResultSetType, getXAExceptionContents, hasLostUpdateOrDeadLockOccurred, 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

db2Tc
protected static final com.ibm.ejs.ras.TraceComponent db2Tc
Constructor Detail

DB2DataStoreHelper
public DB2DataStoreHelper(java.util.Properties props)
This DB2DataStoreHelper constructor creates a new DB2DataStoreHelper 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

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 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

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 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 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, 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 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 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. DB2DataStoreHelper always returns java.sql.ResultSet.CONCUR_READ_ONLY.

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 DB2 lock information needed for the RAS subsystem. The props parameter may include the following properties:

db2Install - DB2 bin directory

outputFile - the output file for storing the lock information. If this property is not specifed, no output is generated and null is returned.

workingDir - a directory with write permission for the method caller where temporary files may be created. If this property is not specified, the current directory is used.
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 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
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 by WebSphere 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.
Since:

WAS 5.0.1

isBatchUpdateSupportedWithAccessIntent
public boolean isBatchUpdateSupportedWithAccessIntent(com.ibm.websphere.appprofile.accessintent.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 being able to support batch updates. In such cases, this method must return false. DB2DataStoreHelper returns false if the concurrency_control the AccessIntent is AccessIntent.CONCURRENCY_CONTROL_OPTIMISTIC, and otherwise returns true.

Specified by:
isBatchUpdateSupportedWithAccessIntent in interface DataStoreHelper
Overrides:
isBatchUpdateSupportedWithAccessIntent in class GenericDataStoreHelper

Parameters:
accessIntent - AccessIntent
Returns:
boolean true if batching is allowed with the given AccessIntent, otherwise false.
Since:

WAS 5.0.2

See Also:
AccessIntent

getLockType
public int getLockType(com.ibm.websphere.appprofile.accessintent.AccessIntent intent)
This method returns a locktype based on the input AccessIntent update hint value. The locktype is used by the perssitence manager to determine whether this select statement is a normal Select, a Select for Update, Select for Update with RS or RR lock.

Specified by:
getLockType in interface DataStoreHelper
Overrides:
getLockType in class GenericDataStoreHelper

Parameters:
intent - An AccessIntent
Returns:
the locktype. The possible values are defined in com.ibm.websphere.rsadaper.WSInteractionSpec:

LOCKTYPE_SELECT
LOCKTYPE_SELECT_FOR_UPDATE
LOCKTYPE_SELECT_FOR_UPDATE_WITH_RS
LOCKTYPE_SELECT_FOR_UPDATE_WITH_RR
See Also:
AccessIntent, com.ibm.websphere.rsadaper.WSInteractionSpec

WebSphere is a trademark of the IBM Corporation in the United States, other countries, or both.

IBM is a trademark of the IBM Corporation in the United States, other countries, or both.

Error Code	SQL State	PortableSQLException subclass
-30081		StaleConnectionException.class
-6036		StaleConnectionException.class
-1229		StaleConnectionException.class
-1224		StaleConnectionException.class
-1035		StaleConnectionException.class
-1034		StaleConnectionException.class
-1015		StaleConnectionException.class
-803		DuplicateKeyException.class
-518		StaleConnectionException.class
-514		StaleConnectionException.class
	58004	StaleConnectionException.class
	S1000	Void.class

Field Summary
protected static com.ibm.ejs.ras.TraceComponent	db2Tc

Constructor Summary
DB2DataStoreHelper(java.util.Properties props) This DB2DataStoreHelper constructor creates a new DB2DataStoreHelper based on the DataStoreHelper properties provided.

Method Summary
void	doConnectionSetup(java.sql.Connection conn) This method configures a connection before first use.
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 DB2DataStoreHelper, 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	getLockType(com.ibm.websphere.appprofile.accessintent.AccessIntent intent) This method returns a locktype based on the input AccessIntent update hint value.
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).
int	getResultSetConcurrency(com.ibm.websphere.appprofile.accessintent.AccessIntent intent) This method determines the result set concurrency based on the specified AccessIntent.
boolean	isBatchUpdateSupportedWithAccessIntent(com.ibm.websphere.appprofile.accessintent.AccessIntent accessIntent) This method is used to determine if CMP Entity Beans can support batch updates with the given 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 DB2 lock information needed for the RAS subsystem.

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

com.ibm.websphere.rsadapter Class DB2DataStoreHelper

db2Tc

DB2DataStoreHelper

doConnectionSetup

doStatementCleanup

findMappingClass

getIsolationLevel

getResultSetConcurrency

showLockInfo

setUserDefinedMap

getPrintWriter

isBatchUpdateSupportedWithAccessIntent

getLockType

com.ibm.websphere.rsadapter
Class DB2DataStoreHelper