type=page
status=published
title=Creating a Session Persistence Module
next=packaging-integrating-delivering.html
prev=adding-container-capabilities.html
~~~~~~

= Creating a Session Persistence Module

[[GSACG00008]][[gkmhj]]


[[creating-a-session-persistence-module]]
== Creating a Session Persistence Module

GlassFish Server enables you to create a session persistence module in
the web container for high availability-related functionality by
implementing the `PersistenceStrategyBuilder` interface . Using the
`PersistenceStrategyBuilder` interface in an HK2 service makes the
session manager extensible because you can implement a new persistence
type without having to modify the web container code.

For information about other high-availability, session persistence
solutions, see "link:../ha-administration-guide/session-persistence-and-failover.html#GSHAG00011[Configuring High Availability Session
Persistence and Failover]" in GlassFish Server Open Source Edition High
Availability Administration Guide.

[[gkmhr]][[GSACG00141]][[implementing-the-persistencestrategybuilder-interface]]

=== Implementing the `PersistenceStrategyBuilder` Interface

You can implement the `PersistenceStrategyBuilder` interface by creating
a new web session manager type.

[source,java]
----

package com.sun.enterprise.web;

import com.sun.enterprise.deployment.runtime.web.SessionManager;
import org.apache.catalina.Context;
import org.jvnet.hk2.annotations.Contract;

@Contract
public interface PersistenceStrategyBuilder {

    public void initializePersistenceStrategy(
            Context ctx,
            SessionManager smBean,
            ServerConfigLookup serverConfigLookup);

    public void setPersistenceFrequency(String persistenceFrequency);

    public void setPersistenceScope(String persistenceScope);

    public void setPassedInPersistenceType(String persistenceType);
}
----

Here is an example of how to implement the `PersistenceStrategyBuilder`
interface by creating a new web session manager and setting a store for
it:

[source,java]
----

@Service(name="xyz")
public class XYZStrategyBuilder implements PersistenceStrategyBuilder {

    private String persistenceFrequency = null;
    private String persistenceScope = null;
    private String persistenceType = null;

    public void init(StandardContext ctx, SessionManager sessionManager,
      ServerConfigLookup serverConfigLookup) {
        // add listeners, valves, etc. to the ctx
        // Set the manager and store
    }

    public void setPersistenceFrequency(String persistenceFrequency) {
        this.persistenceFrequency = persistenceFrequency;
    }

    public void setPersistenceScope(String persistenceScope) {
        this.persistenceScope = persistenceScope;
    }

    public void setPassedInPersistenceType(String persistenceType) {
        this.passedInPersistenceType = persistenceType;
    }
}
----

If a `Manager` is provided, then it will be used in GlassFish Server.


[NOTE]
====
If a backing store is required, it is the responsibility of the
`Manager` to make sure that the `findSession` method correctly uses the
`Store` that the `Manager` provides.
====

[[sthref10]]

Example 8-1 Implementing `PersistenceStrategyBuilder` With a Custom Web
Session Manager

This example defines a session manager type that is named
`MyHASolution`.

[source,java]
----

@Service(name="MyHASolution")
public class MyHASolutionStrategyBuilder implements PersistenceStrategyBuilder {

    private String persistenceFrequency = null;
    private String persistenceScope = null;
    private String persistenceType = null;

    public void init(StandardContext ctx, SessionManager sessionManager,
      ServerConfigLookup serverConfigLookup) {
        // add listeners, valves, etc. to the ctx
        // Set the manager and store
        MyManager myManager = new MyManager(persistenceType, persistenceFrequency);
        // (You could also make this a service and look it up in the habitat.
        // For simplicity we are just doing a new implementation of the class here.)
        MyStore store = new MyStore();
        myManager.setStore(store);
        ctx.setManager(myManager);
    }

    public void setPersistenceFrequency(String persistenceFrequency) {
        this.persistenceFrequency = persistenceFrequency;
    }

    public void setPersistenceScope(String persistenceScope) {
        this.persistenceScope = persistenceScope;
    }

    public void setPassedInPersistenceType(String persistenceType) {
        this.passedInPersistenceType = persistenceType;

    }

}
----

[[sthref11]]

Example 8-2 Session Manager Configuration in the `glassfish-web.xml`
File

This example sets the `persistence-type` attribute of the
`session-manager` element of `glassfish-web.xml` to `myHASolution`

Based on the `domain.xml` and `glassfish-web.xml` settings, the web
container looks up the appropriate `PersistenceStrategyBuilder`
interface in the Habitat and uses it.

[source,xml]
----
       <glassfish-web-app>
         <session-config>
           <session-manager persistence-type="myHASolution"/>
         <session-config>
       <glassfish-web-app>
----