org.springframework.jdbc.datasource.lookup
Class IsolationLevelDataSourceRouter
java.lang.Object
   org.springframework.jdbc.datasource.AbstractDataSource
org.springframework.jdbc.datasource.AbstractDataSource
       org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource
org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource
           org.springframework.jdbc.datasource.lookup.IsolationLevelDataSourceRouter
org.springframework.jdbc.datasource.lookup.IsolationLevelDataSourceRouter
- All Implemented Interfaces: 
- Wrapper, CommonDataSource, DataSource, InitializingBean
- public class IsolationLevelDataSourceRouter 
- extends AbstractRoutingDataSource
DataSource that routes to one of various target DataSources based on the
 current transaction isolation level. The target DataSources need to be
 configured with the isolation level name as key, as defined on the
 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),- AbstractRoutingDataSource.setDefaultTargetDataSource(java.lang.Object),- TransactionDefinition.ISOLATION_READ_UNCOMMITTED,- TransactionDefinition.ISOLATION_READ_COMMITTED,- TransactionDefinition.ISOLATION_REPEATABLE_READ,- TransactionDefinition.ISOLATION_SERIALIZABLE,- JtaTransactionManager
 
 
 
 
 
 
| Methods inherited from class java.lang.Object | 
| clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait | 
 
IsolationLevelDataSourceRouter
public IsolationLevelDataSourceRouter()
resolveSpecifiedLookupKey
protected Object resolveSpecifiedLookupKey(Object lookupKey)
- Supports Integer values for the isolation level constants
 as well as isolation level names as defined on the
 TransactionDefinition interface.
 
- 
- Overrides:
- resolveSpecifiedLookupKeyin class- AbstractRoutingDataSource
 
- 
- Parameters:
- lookupKey- the lookup key object as specified by the user
- Returns:
- the lookup key as needed for matching
 
determineCurrentLookupKey
protected Object 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:
- determineCurrentLookupKeyin class- AbstractRoutingDataSource
 
- 
 
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