Apache Cayennea Java ORM Alternativeby Andrus Adamchik @andrus_a

About Me

• Member and VP of the Apache Software Foundation.• Run a company called ObjectStyle.• Open source developer: ORM, dependency injection, REST,

no-container, etc.

What is Apache Cayenne• A mature user-friendly Java ORM with modeling tools.• An alternative object persistence philosophy.• Current dev version is 4.0 (209 new features and bug fixes).• Used by commercial, government and educational orgs on

all continents.

History• 2001: Inception.• 2002: First Alpha Release and a large production

deployment.• 2006: "ObjectStyle Cayenne" becomes "Apache Cayenne".• 2016: Active project with great community.

"Community over Code"• A community-driven project under Apache Foundation

umbrella.• Dozens of contributors over the years.• 8 PMC (Project Management Committee) members.• Meritocracy - anyone can earn a vote by contributing.

Demo

Project Setup• CayenneModeler helps to setup and maintain the project.• DB-first approach to ORM gets you started quickly with

existing DB.• Auto sync of DB changes without overriding custom

mapping.

Starting Cayenne

Obtaining ObjectContext

Running a Query

Editing and Saving Objects

Cayenne vs. JPA / Hibernate

Transactions• JPA/Hibernate were born in the EJB world. Both are

transaction-centric.• Cayenne transactions are implicit, unless you want it

otherwise.• Cayenne is not connected to DB between JDBC operations.• Better connection pool reuse and no user TX code.

ObjectContext• An isolated unit of work (each context has its own copy of objects).

• Not holding any open resources (connections, etc.), doesn't need to be closed.

• Fairly cheap - you can create as many instances as you need.

• Can be nested (similar to nested transactions, only in memory).

• Object graph can be expanded lazily as object relationships are traversed.

Persistent Object• Framework-provided superclass - CayenneDataObject.• No pollution with ORM annotations.• Generic property access API.• Generic mapping - can be created in runtime.

Other Good Things

Dependency Injection (DI)

Nested Contexts

Remote Object Persistence

Caching

Handling Large Result Sets

Batch Iterator

cayenne-crypto

Why Cayenne?• Mature, performant, user-friendly.• Opinionated on the side of usability.• Not obsessed about transactions. Smooth object graph

navigation.• Community-driven. You can have a voice!

Questions?

• @ApacheCayenne• http://cayenne.apache.org/• https://github.com/apache/cayenne