Eclipse JPA
Gordon Yorke
EclipseLink Architecture Committee Member,
TopLink Core Technical Lead,
JPA 2.0 Expert Group Member
gordon.yorke@oracle.com

What you will learn
• Eclipse Persistence Services Project (EclipseLink)
 Components
• Focus on EclipseLink JPA
 JPA 2.0 RI status
 EclipseLink Extensions

Eclipse Persistence Services
• Eclipse runtime project
 Nicknamed “EclipseLink”
 Latest version 1.0.2
• Comprehensive
 EclipseLink JPA: Object-Relational
 EclipseLink MOXy: Object-XML
 EclipseLink SDO: Service Data Objects
 EclipseLink DBWS: Database Web Services
 EclipseLink EIS: Non-Relational using JCA

Tidbits
• First comprehensive open source persistence solution
• Based upon product with 12 years of commercial
usage
• Same code base that was used to create TopLink
Essentials
• Highly optimizable through precise configurations
• Great performance

EclipseLink JPA
• JPA 1.0 compliant implementation
• JPA 2.0 in development for RI
• Keep up to date at:
 http://wiki.eclipse.org/EclipseLink/Development/JPA_2.0
• Any JDBC/SQL compliant database
 Database specific support for Oracle, MySQL, Derby,
SQLServer, PostgreSQL et al.
• Extensible and pluggable
• plus many valuable advanced features
 Caching, locking …

EclipseLink JPA Extensions
• Weaving
 Lazy loading @Basic, @OneToOne, @ManyToOne
 Performance options like change tracking
• Mapping
 @PrivateOwned, @JoinFetch
 @Converter, @TypeConverter, @ObjectTypeConverter
• @NamedStoredProcedureQuery
 IN/OUT/INOUT parameters, multiple cursor results
• Extensions supported through annotations and XML
• Query hints
 refreshing, locking, parameter binding …

Extensions - Locking
• Data Locking policies
 Optimistic: Numeric, Timestamp, All fields, Selected fields,
Changed field
 Pessimistic

Extensions - Entity Caching
• Entity caching
 L2 shared across transactions/users
 Coordination in a clustered deployment
 Can support 3rd party distributed cache.
• Application specific configuration
 Caching: per Entity or per Persistence Unit
 eclipselink.cache.shared(default|<entity>)
 Cache Type and Size: Weak, Soft-Weak, Full
 eclipselink.cache.type(default|<entity>)
 Expiration/Invalidation
 Time to live, Time of day, API
 Coordination (cluster-messaging)
 Messaging: JMS, RMI, RMI-IIOP, …
 Mode: SYNC, SYNC+NEW, INVALIDATE, NONE

Performance and Tuning
• Highly configurable and tunable
 Principle: minimize and optimize database calls
 Enable application specific tuning
• Flexibility allows efficient business models and
relational schemas to be used
• Leverages underlying performance tuning features
 Java, JDBC and the underlying database technology
 Batch Reading, Batch Writing, Joined Reading, etc…

More Information
• www.eclipse.org/eclipselink
• Newsgroup: eclipse.technology.eclipselink
• Wiki: wiki.eclipse.org/EclipseLink
• Mailing Lists:
 eclipselink-dev@eclipse.org
 eclipselink-users@eclipse.org
• Blogs
 Committer Team blog: eclipselink.blogspot.com