22 Performing Transactions (.NET)
The instructions do not provide detailed transaction API usage. See Using the Transaction Framework API in Developing Applications with Oracle Coherence.
The following sections are included in this chapter and are required to perform transactions:
- Using the Transaction API within an Entry Processor
.NET clients perform cache operations within a transaction by leveraging the Transaction Framework API. - Creating a Stub Class for a Transactional Entry Processor
An entry processor stub class allows a client to use the transactional entry processor on the cluster. - Registering a Transactional Entry Processor User Type
Custom user types must be registered for the Java transactional entry processor in the cluster-side POF configuration file and for the client stub in the client-side POF configuration file. - Configuring the Cluster-Side Transactional Caches
Transactions require a transactional cache to be defined in the cluster-side cache configuration file. - Configuring the Client-Side Remote Cache
Remote clients require a remote cache to connect to the cluster's proxy and run a transactional entry processor. - Using a Transactional Entry Processor from a .NET Client
A client invokes an entry processor stub class the same way any entry processor is invoked.
Parent topic: Creating .NET Extend Clients
Using the Transaction API within an Entry Processor
Example 22-1 demonstrates an entry processor that performs a simple update
operation within a transaction using the transaction API. At run time, the class must be located on the classpath of the Coherence proxy server.
Example 22-1 Entry Processor for Extend Client Transaction
package coherence.tests; import com.tangosol.coherence.transaction.Connection; import com.tangosol.coherence.transaction.ConnectionFactory; import com.tangosol.coherence.transaction.DefaultConnectionFactory; import com.tangosol.coherence.transaction.OptimisticNamedCache; import com.tangosol.coherence.transaction.exception.PredicateFailedException; import com.tangosol.coherence.transaction.exception.RollbackException; import com.tangosol.coherence.transaction.exception.UnableToAcquireLockException; import com.tangosol.util.Filter; import com.tangosol.util.InvocableMap; import com.tangosol.util.extractor.IdentityExtractor; import com.tangosol.util.filter.EqualsFilter; import com.tangosol.util.processor.AbstractProcessor; public class MyTxProcessor extends AbstractProcessor implements PortableObject { public Object process(InvocableMap.Entry entry) { // obtain a connection and transaction cache ConnectionFactory connFactory = new DefaultConnectionFactory(); Connection conn = connFactory.createConnection("TransactionalCache"); OptimisticNamedCache cache = conn.getNamedCache("MyTxCache"); conn.setAutoCommit(false); // get a value for an existing entry String sValue = (String) cache.get("existingEntry"); // create predicate filter Filter predicate = new EqualsFilter(IdentityExtractor.INSTANCE, sValue); try { // update the previously obtained value cache.update("existingEntry", "newValue", predicate); } catch (PredicateFailedException e) { // value was updated after it was read conn.rollback(); return false; } catch (UnableToAcquireLockException e) { // row is being updated by another tranaction conn.rollback(); return false; } try { conn.commit(); } catch (RollbackException e) { // transaction was rolled back return false; } return true; } public void readExternal(PofReader in) throws IOException { } public void writeExternal(PofWriter out) throws IOException { } }
Parent topic: Performing Transactions (.NET)
Creating a Stub Class for a Transactional Entry Processor
Example 22-2 demonstrate an entry processor stub class for the transactional entry processor created in Example 22-1.
Example 22-2 Transaction Entry Processor .NET Stub Class
using Tangosol.IO.Pof; using Tangosol.Net.Cache; using Tangosol.Util.Processor; namespace Coherence.Tests{ public class MyTxProcessor : AbstractProcessor, IPortableObject { public MyTxProcessor() { } public override object Process(IInvocableCacheEntry entry) { return null; } public void ReadExternal(IPofReader reader) { } public void WriteExternal(IPofWriter writer) { } } }
Parent topic: Performing Transactions (.NET)
Registering a Transactional Entry Processor User Type
MyTxProcessor
class that was created in Example 22-1 and the client stub class that was created in Example 22-2, respectively.
Cluster-side POF configuration:
<?xml version="1.0"?> <pof-config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.oracle.com/coherence/coherence-pof-config" xsi:schemaLocation="http://xmlns.oracle.com/coherence/coherence-pof-config coherence-pof-config.xsd"> <user-type-list> <include>coherence-pof-config.xml</include> <include>txn-pof-config.xml</include> <user-type> <type-id>1599</type-id> <class-name>coherence.tests.MyTxProcessor</class-name> </user-type> </user-type-list> </pof-config>
Client-side POF configuration:
<?xml version="1.0"?> <pof-config xmlns="http://schemas.tangosol.com/pof" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://schemas.tangosol.com/pof assembly://Coherence/Tangosol.Config/pof-config.xsd"> <user-type-list> <include>coherence-pof-config.xml</include> <user-type> <type-id>1599</type-id> <class-name>Coherence.Tests.MyTxProcessor</class-name> </user-type> </user-type-list> </pof-config>
Parent topic: Performing Transactions (.NET)
Configuring the Cluster-Side Transactional Caches
The following example creates a transactional cache that is named MyTxCache
, which is the cache name that was used by the entry processor in Example 22-1. The configuration also includes a proxy scheme and a distributed cache scheme that are required to execute the entry processor from a remote client. The proxy is configured to accept client TCP/IP connections on localhost
at port 7077
. See Configuring Extend Proxies.
<?xml version='1.0'?> <cache-config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.oracle.com/coherence/coherence-cache-config" xsi:schemaLocation="http://xmlns.oracle.com/coherence/coherence-cache-config coherence-cache-config.xsd"> <caching-scheme-mapping> <cache-mapping> <cache-name>MyTxCache</cache-name> <scheme-name>example-transactional</scheme-name> </cache-mapping> <cache-mapping> <cache-name>dist-example</cache-name> <scheme-name>example-distributed</scheme-name> </cache-mapping> </caching-scheme-mapping> <caching-schemes> <transactional-scheme> <scheme-name>example-transactional</scheme-name> <service-name>TransactionalCache</service-name> <thread-count-min>2</thread-count-min> <thread-count-max>10</thread-count-max> <high-units>15M</high-units> <task-timeout>0</task-timeout> <autostart>true</autostart> </transactional-scheme> <distributed-scheme> <scheme-name>example-distributed</scheme-name> <service-name>DistributedCache</service-name> <backing-map-scheme> <local-scheme/> </backing-map-scheme> <autostart>true</autostart> </distributed-scheme> <proxy-scheme> <service-name>ExtendTcpProxyService</service-name> <autostart>true</autostart> </proxy-scheme> </caching-schemes> </cache-config>
Parent topic: Performing Transactions (.NET)
Configuring the Client-Side Remote Cache
The following example configures a remote cache to connect to a proxy that is located on localhost
at port 7077
. In addition, the name of the remote cache (dist-example
) must match the name of a cluster-side cache that is used when initiating the transactional entry processor.
<?xml version='1.0'?> <cache-config xmlns="http://schemas.tangosol.com/cache" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://schemas.tangosol.com/cache assembly://Coherence/Tangosol.Config/cache-config.xsd"> <caching-scheme-mapping> <cache-mapping> <cache-name>dist-example</cache-name> <scheme-name>extend</scheme-name> </cache-mapping> </caching-scheme-mapping> <caching-schemes> <remote-cache-scheme> <scheme-name>extend</scheme-name> <service-name>ExtendTcpCacheService</service-name> <initiator-config> <tcp-initiator> <remote-addresses> <socket-address> <address>localhost</address> <port>7077</port> </socket-address> </remote-addresses> </tcp-initiator> <outgoing-message-handler> <request-timeout>30s</request-timeout> </outgoing-message-handler> </initiator-config> </remote-cache-scheme> </caching-schemes> </cache-config>
Parent topic: Performing Transactions (.NET)
Using a Transactional Entry Processor from a .NET Client
The following example demonstrates a client that uses the entry processor stub class and results in an invocation of the transactional entry processor that was created in Example 22-1:
INamedCache cache = CacheFactory.GetCache("dist-example"); object result = cache.Invoke( "AnyKey", new MyTxProcessor()); Console.Out.WriteLine("Result of extend transaction execution: " + result );
Parent topic: Performing Transactions (.NET)