The document discusses multi-tenancy in Java EE applications, highlighting the architecture where a single application instance serves multiple clients. It covers challenges such as data separation, UI customization, and resource provisioning, along with pros and cons of multi-tenancy models. Additionally, it provides implementation strategies using JPA and Hibernate, including various tenant identification methods and examples of database strategy options.

1. Supporting Multi-tenancy
Applications with Java EE
Rodrigo Cândido da Silva
@rcandidosilva
JavaOne 2014
CON4959

2. About Me
• Brazilian guy ;)
• Work for Integritas company
• http://integritastech.com
• Software Architect
• Java Platform
• JUG Leader of GUJavaSC
• http://gujavasc.org
• Twitter
• @rcandidosilva
• Personal
• http://rodrigocandido.me

3. Agenda
• Cloud Services Model
• SaaS Market
• Multi-tenancy
• Challenges
• Pros and Cons
• Strategy Types
• Java EE + Multi-tenancy
• Multi-tenancy at Cloud

4. Cloud Services Model

5. SaaS Market

6. Multi-tenancy
• One application
instance to multiple
clients (tenant)
• Inverse of the multiple
instances architecture

7. Multi-instances vs. Multi-tenant

8. Multi-instances vs. Multi-tenant
Feature Multi-instances Multi-tenant
Cost Structure Can support only tiered or
flat pricing
Supports usage based pricing
as well as tiered or flat
Resources Dedicated resources Shared resources
Operation and
Maintenance
Manage and administer
as many instances as
customers
Manager and administer a
single instance for a number
of customers
Scalable Model Not scalable. As the
number of customers
increase the maintenance
requirements increase
proporcionally
Scalable, since a number of
customers are serviced by
one instance

9. Cloud != Multi-tenancy

10. Challenges
• Data separation
• UI and business rules customization
• Access control by tenant
• Resource provisioning
• Integration
• Application update
• Failover tolerance

11. Pros and Cons
• Pros
• Low maintenance cost
• Same source code for all customers
• High scalability
• Sharing resources between customers
• Cons
• High complexity
• Separation by tenant-id
• More failure risks
• If code breaks -> breaks to all customers
• Low flexibility available to the customers

12. Multi-tenancy
• Adoption levels
• Level 1 (Customized)
• [N] applications and [N] databases
• Level 2 (Configurable)
• [1] application and [N] databases
• Level 3 (Scalable)
• [1] application and [1] database

13. Level 1 - Customized
• [N] applications and [N] databases

14. Level 2 - Configurable
• [1] application and [N] databases

15. Level 3 - Scalable
• [1] application and [1] database

16. What is the Best Choice?
• Depends on…
• Data Customization
• Addition or removal of columns in the data store
• Function Customization
• The functionality executed for a specific business can vary by
customers
• Process Customization
• The business process can vary for each customer
• Licensing Features
• The product has multiple licenses which define the functionality
that is enabled for the customer

17. Database Strategy
Separate Databases
Separate Tables
Shared Database

18. Database Strategy
Feature Separate DBs Separate Tables Shared Database
Data
Customization
Security
Inter-dependency
and Performance
Scalable Model
Customer On-boarding

19. Java EE + Multi-tenancy
• Database
• JPA + Multi-tenancy
• UI Customization
• JSF + Multi-tenancy
• Java EE 8 with Cloud support

20. JPA + Multi-tenancy
• There is no standard at this time
• EclipseLink
• Multi-tenancy support using @Multitenant
• Multitenant strategies
• @Multitenant(SINGLE_TABLE) – default
• @Multitenant(TABLE_PER_TENANT)
• @Multitenant(VPD)
• Hibernate
• Supports tenant identifier features
• MultiTenantConnectionProvider
• CurrentTenantIdentifierResolver

21. EclipseLink SINGLE_TABLE
@Entity
@Table(name=“EMP”)
@Multitenant(SINGLE_TABLE)
@TenantDiscriminatorColumn(name = “TENANT_ID”,
contextProperty = “tenant-id”)
public class Employee {
...
}
HashMap properties = new HashMap();
properties.put("tenant.id", "707");
...
EntityManager em = Persistence
.createEntityManagerFactory(
"multi-tenant”,properties)
.createEntityManager();
<persistence-unit name="multi-tenant">
...
<properties>
<property name="tenant.id"
value="707"/>
...
</properties>
</persistence-unit>

22. EclipseLink TABLE_PER_TENANT
<entity class="Employee">
<multitenant type="TABLE_PER_TENANT">
<tenant-table-discriminator type="SCHEMA" context-property="
eclipselink.tenant-id"/>
</multitenant>
<table name="EMP">
...
</entity>
@Entity
@Table(name=“EMP”)
@Multitenant(TABLE_PER_TENANT)
@TenantTableDiscriminator(type=SCHEMA,
contextProperty="eclipselink.tenant-id")
public class Employee {
...
}

23. EclipseLink VPD
@Entity
@Multitenant
@TenantDiscriminatorColumn(name = "USER_ID",
contextProperty = "tenant.id")
@Cacheable(false)
public class Task implements Serializable {
...
CALL DBMS_RLS.ADD_POLICY
('SCOTT', 'TASK', 'todo_list_policy',
'SCOTT', 'ident_func', 'select, update,
delete'));
<properties>
<property name="eclipselink.session.customizer"
value="example.VPDSessionCustomizer" />
<property name="eclipselink.session-event-listener"
value="example.VPDSessionEventAdapter" />
<property
name="eclipselink.jdbc.exclusive-connection.mode"
value="Always" />
</properties>

24. Hibernate MultiTenantConnectionProvider
public class MultiTenantProvider
implements MultiTenantConnectionProvider {
public Connection getConnection(String tenantIdentifier) throws
SQLException {
final Connection connection = getAnyConnection();
connection.createStatement().execute(
"SET SCHEMA '" + tenantIdentifier + "'");
return connection;
}
public void releaseConnection(String tenantIdentifier, Connection
connection) throws SQLException {
releaseAnyConnection(connection);
}
}

25. Hibernate CurrentTenantIdentifierResolver
public class SchemaResolver implements
CurrentTenantIdentifierResolver {
@Override
public String resolveCurrentTenantIdentifier() {
return resolveTenant();
}
@Override
public boolean validateExistingCurrentSessions() {
return false;
}
}

26. Hibernate persistence.xml
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/
persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://
java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
<persistence-unit name="default">
<properties>
<property name="javax.persistence.provider"
value="org.hibernate.ejb.HibernatePersistence" />
<property name="hibernate.multiTenancy" value="SCHEMA"/>
<property name="hibernate.tenant_identifier_resolver"
value="yourpackage.SchemaResolver"/>
<property name="hibernate.multi_tenant_connection_provider"
value="yourpackage.MultiTenantProvider"/>
</properties>
</persistence-unit>
</persistence>

27. JPA Caching
• Shared Cache disabled

28. JPA Caching
• Shared Cache by tenant

29. JSF + Multi-tenancy
• Flexible software architecture
• Artifacts packaged in separated JAR’s
• Composition at runtime
• Templates and contracts
• Resource library
• Look-and-feel customization
• RenderKit features
• Localization support

30. JSF Facelets
The Facelets Gazette
Site
Navigation
●Events
●Docs
●Forums
About Contact Site Map
Template File name
_template.html
Insertion points
Resources
css classes, scripts, images

31. JSF Multi-templating
• Resource Library Contracts
• Convention
• All available contracts discovered at startup
• Configuration
• faces-config.xml by <resource-library-contract>
• contracts attribute in <f:view>
<web-app-root>/contracts
contractA
contractB
• Declared Templates
• Declared Insertion contractC
Points
• Declared Resources
• Declared Templates
• Declared Insertion Points
• Declared Resources
• Declared Templates
• Declared Insertion Points
• Declared Resources
JAR files in WEB-INF/lib
contractD
contractE
• Declared Templates
• Declared Insertion contractF
Points
• Declared Resources
• Declared Templates
• Declared Insertion Points
• Declared Resources
• Declared Templates
• Declared Insertion Points
• Declared Resources

32. JSF Multi-templating
<web-app-root>/contracts
contractA
contractB
• Declared Templates
• Declared Insertion contractC
Points
• Declared Resources
• Declared Templates
• Declared Insertion Points
• Declared Resources
• Declared Templates
• Declared Insertion Points
• Declared Resources
JAR files in WEB-INF/lib
contractD
contractE
• Declared Templates
• Declared Insertion contractF
Points
• Declared Resources
• Declared Templates
• Declared Insertion Points
• Declared Resources
• Declared Templates
• Declared Insertion Points
• Declared Resources
Set of available contracts
Facelet 1
<f:view contracts="contractA">
...
faces-config.xml
Facelet 2 Facelet 3

33. JSF Multi-templating
<html xmlns="http://www.w3.org/1999/xhtml”
xmlns:h="http://java.sun.com/jsf/html”
xmlns:ui="http://java.sun.com/jsf/
facelets">
<body>
<ui:composition template="#{template}”>
...
</ui:composition>
</body>
</html>
<?xml version="1.0" encoding="UTF-8"?>
<web-app>
<context-param>
<param-name>javax.faces.view.TEMPLATE</param-name>
<param-value>mybusiness</param-value>
</context-param>
</web-app>

34. Demo
• EclipseLink MySports Demo
• http://wiki.eclipse.org/EclipseLink/Examples/MySports
• http://git.eclipse.org/c/eclipselink/examples.git

35. Questions
?

36. References
• http://msdn.microsoft.com/en-us/library/aa479086.aspx
• https://developers.google.com/appengine/docs/java/multitenancy/
• http://www.ibm.com/developerworks/java/library/j-multitenant-java/index.html
• http://www.eclipse.org/eclipselink/documentation/2.4/jpa/extensions/a_multitenant.htm
• http://2012.con-fess.com/sessions/-/details/122/JSF-and-JavaEE-7-for-multi-tenant-applications
• http://jdevelopment.nl/jsf-22/
• http://picketlink.org
• https://developers.google.com/appengine/docs/java/multitenancy/
• http://www.jboss.org/quickstarts/picketlink/picketlink-authentication-idm-multi-tenancy/
• http://wiki.eclipse.org/EclipseLink/Examples/MySports

37. Thank you!
@rcandidosilva
rodrigocandido.me