Class IsolationLevelDataSourceRouter
- All Implemented Interfaces:
Wrapper
,CommonDataSource
,DataSource
,InitializingBean
TransactionDefinition interface
.
This is particularly useful in combination with JTA transaction management
(typically through Spring's JtaTransactionManager
).
Standard JTA does not support transaction-specific isolation levels. Some JTA
providers support isolation levels as a vendor-specific extension (e.g. WebLogic),
which is the preferred way of addressing this. As alternative (e.g. on WebSphere),
the target database can be represented through multiple JNDI DataSources, each
configured with a different isolation level (for the entire DataSource).
The present DataSource router allows to transparently switch to the
appropriate DataSource based on the current transaction's isolation level.
The configuration can for example look like this, assuming that the target DataSources are defined as individual Spring beans with names "myRepeatableReadDataSource", "mySerializableDataSource" and "myDefaultDataSource":
<bean id="dataSourceRouter" class="org.springframework.jdbc.datasource.lookup.IsolationLevelDataSourceRouter"> <property name="targetDataSources"> <map> <entry key="ISOLATION_REPEATABLE_READ" value-ref="myRepeatableReadDataSource"/> <entry key="ISOLATION_SERIALIZABLE" value-ref="mySerializableDataSource"/> </map> </property> <property name="defaultTargetDataSource" ref="myDefaultDataSource"/> </bean>Alternatively, the keyed values can also be data source names, to be resolved through a
DataSourceLookup
: by default, JNDI
names for a standard JNDI lookup. This allows for a single concise definition
without the need for separate DataSource bean definitions.
<bean id="dataSourceRouter" class="org.springframework.jdbc.datasource.lookup.IsolationLevelDataSourceRouter"> <property name="targetDataSources"> <map> <entry key="ISOLATION_REPEATABLE_READ" value="java:comp/env/jdbc/myrrds"/> <entry key="ISOLATION_SERIALIZABLE" value="java:comp/env/jdbc/myserds"/> </map> </property> <property name="defaultTargetDataSource" value="java:comp/env/jdbc/mydefds"/> </bean>Note: If you are using this router in combination with Spring's
JtaTransactionManager
,
don't forget to switch the "allowCustomIsolationLevels" flag to "true".
(By default, JtaTransactionManager will only accept a default isolation level
because of the lack of isolation level support in standard JTA itself.)
<bean id="transactionManager" class="org.springframework.transaction.jta.JtaTransactionManager"> <property name="allowCustomIsolationLevels" value="true"/> </bean>
- Since:
- 2.0.1
- Author:
- Juergen Hoeller
- See Also:
-
AbstractRoutingDataSource.setTargetDataSources(java.util.Map<java.lang.Object, java.lang.Object>)
AbstractRoutingDataSource.setDefaultTargetDataSource(java.lang.Object)
TransactionDefinition.ISOLATION_READ_UNCOMMITTED
TransactionDefinition.ISOLATION_READ_COMMITTED
TransactionDefinition.ISOLATION_REPEATABLE_READ
TransactionDefinition.ISOLATION_SERIALIZABLE
JtaTransactionManager
-
Field Summary
Fields inherited from class org.springframework.jdbc.datasource.AbstractDataSource
logger
-
Constructor Summary
-
Method Summary
Modifier and TypeMethodDescriptionprotected Object
Determine the current lookup key.protected Object
resolveSpecifiedLookupKey
(Object lookupKey) Supports Integer values for the isolation level constants as well as isolation level names as defined on theTransactionDefinition interface
.Methods inherited from class org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource
afterPropertiesSet, determineTargetDataSource, getConnection, getConnection, getResolvedDataSources, getResolvedDefaultDataSource, isWrapperFor, resolveSpecifiedDataSource, setDataSourceLookup, setDefaultTargetDataSource, setLenientFallback, setTargetDataSources, unwrap
Methods inherited from class org.springframework.jdbc.datasource.AbstractDataSource
getLoginTimeout, getLogWriter, getParentLogger, setLoginTimeout, setLogWriter
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Methods inherited from interface javax.sql.CommonDataSource
createShardingKeyBuilder
Methods inherited from interface javax.sql.DataSource
createConnectionBuilder
-
Constructor Details
-
IsolationLevelDataSourceRouter
public IsolationLevelDataSourceRouter()
-
-
Method Details
-
resolveSpecifiedLookupKey
Supports Integer values for the isolation level constants as well as isolation level names as defined on theTransactionDefinition interface
.- Overrides:
resolveSpecifiedLookupKey
in classAbstractRoutingDataSource
- Parameters:
lookupKey
- the lookup key object as specified by the user- Returns:
- the lookup key as needed for matching
-
determineCurrentLookupKey
Description copied from class:AbstractRoutingDataSource
Determine the current lookup key. This will typically be implemented to check a thread-bound transaction context.Allows for arbitrary keys. The returned key needs to match the stored lookup key type, as resolved by the
AbstractRoutingDataSource.resolveSpecifiedLookupKey(java.lang.Object)
method.- Specified by:
determineCurrentLookupKey
in classAbstractRoutingDataSource
-