InformixDataStoreHelper (IBM WebSphere Application Server [adapter])

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

public class InformixDataStoreHelper
extends GenericDataStoreHelper
implements java.io.Serializable

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

Error Code SQL State PortableSQLException subclass

-79735 StaleConnectionException.class

-79716 StaleConnectionException.class

-43207 StaleConnectionException.class

-27002 StaleConnectionException.class

-25580 StaleConnectionException.class

-908 StaleConnectionException.class

-268 DuplicateKeyException.class

43012 StaleConnectionException.class

See Also:
Serialized Form

Field Summary

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

InformixDataStoreHelper(java.util.Properties props)
          This InformixDataStoreHelper constructor creates a new InformixDataStoreHelper 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 InformixDataStoreHelper, 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.

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.

void setUserDefinedMap(java.util.Map newmap)
          This method configures a user-defined SQLException map that supersedes default SQLException mappings for the DataStoreHelper.

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

calcPartitionNumber, doConnectionCleanup, getLockType, getMetaData, getResultSetType, getXAExceptionContents, hasLostUpdateOrDeadLockOccurred, isBatchUpdateSupportedWithAccessIntent, isConnectionError, mapException, mapException, modifyXAFlag, processGenericCredentials, processSQL, processSQL, showLockInfo

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

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

The DataStoreHelper properties for InformixDataStoreHelper include a an integer property, informixLockModeWait, representing Informix's timeout when waiting for a lock. A value greater than 0 indicates the number of seconds Informix waits for a lock, after which Informix throws an exception. A value of 0 means Informix does not wait for locks at all, immediately throwing an exception. A value less than 0 means Informix will wait indefinitely, until the lock it is waiting for is released. Informix's default behavior is to immediately throw an exception. However, WebSphere's default setting for informixLockModeWait is 2, meaning Informix waits for a lock for two seconds before throwing an exception.

Parameters:
props - DataStoreHelper properties.

Method Detail

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 InformixDataStoreHelper, 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 InformixDataStoreHelper is Connection.TRANSACTION_REPEATABLE_READ.
In the case where an AccessIntent is specified, InformixDataStoreHelper 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 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:
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. InformixDataStoreHelper 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

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.

The following actions are prohibited in this method:

Changing any standard connection properties found on the java.sql.Connection API. This includes TransactionIsolationLevel, AutoCommit, Catalog, ReadOnly, TypeMap, and Holdability.

Closing the connection.

The InformixDataStoreHelper configures the Informix LOCK MODE WAIT based on the informixLockModeWait DataStoreHelper property. A value greater than 0 indicates the number of seconds Informix waits for a lock, after which Informix throws an exception. The informixLockModeWait value, 0, means Informix does not wait for locks at all, immediately throwing an exception. A value less than 0 means Informix will wait indefinitely, until the lock it is waiting for is released. Informix's default behavior is to immediately throw an exception. However, WebSphere's default setting for informixLockModeWait is 2, meaning Informix waits for a lock for two seconds before throwing an exception.

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

InformixDataStoreHelper resets all of the statement properties listed above except for the cursorName and queryTimeout properties.

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.

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

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
-79735		StaleConnectionException.class
-79716		StaleConnectionException.class
-43207		StaleConnectionException.class
-27002		StaleConnectionException.class
-25580		StaleConnectionException.class
-908		StaleConnectionException.class
-268		DuplicateKeyException.class
43012		StaleConnectionException.class

Constructor Summary
InformixDataStoreHelper(java.util.Properties props) This InformixDataStoreHelper constructor creates a new InformixDataStoreHelper 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 InformixDataStoreHelper, 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.
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.
void	setUserDefinedMap(java.util.Map newmap) This method configures a user-defined SQLException map that supersedes default SQLException mappings for the DataStoreHelper.

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 InformixDataStoreHelper

InformixDataStoreHelper

findMappingClass

getIsolationLevel

getResultSetConcurrency

doConnectionSetup

doStatementCleanup

setUserDefinedMap

getPrintWriter

com.ibm.websphere.rsadapter
Class InformixDataStoreHelper