New Persistence Features in Spring Roo 1.1
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Spring Roo 1.1 introduces several new persistence features including incremental database reverse engineering, integration with Apache Solr/Lucene for search, and support for alternative persistence technologies through add-ons. It allows generating JPA entity classes from live databases and automatically updating them as the schema changes. Entities can be made searchable with Solr with just one command. The Hades add-on also provides an alternative data access layer option with a repository pattern.
![Spring Roo DBRE Commands
• database introspect --schema <name> [--file <name>]
– Displays database metadata in XML format in the Roo shell
– Optional --file <file name> saves metadata to specified file
– Provides a preview of the mappings used in the final model](https://image.slidesharecdn.com/springonepersistence2010-101028042633-phpapp02/85/New-Persistence-Features-in-Spring-Roo-1-1-12-320.jpg)
![Spring Roo DBRE Commands
• database reverse engineer [--schema <name>] [--
package <name>]
– Creates entities in the specified package
– --schema and --package options required only for first time
run of command
– Automatically generates type and field names from table
and column names
– JPA-annotated fields and getters/setters saved in AspectJ
ITDs, eg Person_Roo_DbManaged.aj](https://image.slidesharecdn.com/springonepersistence2010-101028042633-phpapp02/85/New-Persistence-Features-in-Spring-Roo-1-1-13-320.jpg)
New Persistence Features in Spring Roo 1.1
- 1. Chicago, October 19 - 22, 2010 New Persistence Features in Spring Roo 1.1 Stefan Schmidt
- 2. Agenda • Spring Roo’s Approach to Persistence • Incremental Database Reverse Engineering • Apache Solr / Lucene Integration • Alternative Persistence Technologies
- 3. Spring Roo’s Approach to Persistence
- 4. Peristence Choices • JPA2 for ORM – 4 choices of ORM providers • Hibernate • EclipseLink • OpenJPA • DataNucleus (DN1 supported for GAE, DN2 used by VMforce) • 12+ Database choices – constantly growning list of DBs to choose from – popular ones: MySQL, Postgres, HSQLDB (for dev) • Switch out ORM and / or DB with a single command – persistence setup --provider HIBERNATE --database MYSQL
- 5. No DAOs? • No DAO layer by default – Objections: • testing • separation of concern • pluggable implementations • non JPA persistence • security authorizations • security auditing • finders • architectural reasons
- 6. Feature Extension Points • Add-ons can contribute persistence feature extensions via ITDs – Finder add-on is a good example • Every @RooEntity exposes the JPA entity manager – use for creating custom type-safe queries via Criteria API – getting access to the underlying ORM
- 8. Alternatives to Roo’s Incremental DBRE • Eclipse “JPA Entities from tables” wizard – Generates entities from a JDBC connection – Can be tailored to change generated type and field names – Does not handle tables with no primary keys • JPA Implementation Tools
- 9. Limitations of Existing DBRE Tools • Lack of incremental reverse engineering • Complex and long-winded wizard style interactions • Missing entity lifecycle management – Application requires manual adjustment if the datamodel changes
- 10. Introducing Roo’s Incremental Database Reverse Engineering • DBRE was the most requested feature for Spring Roo • Introspect relational databases such as Oracle, MySQL, PostgreSQL and Microsoft SQL Server • Reverse engineer complex schemas into Java entities in seconds • Creates and maintains relationships with JPA 2.0 annotations • Incrementally updates your domain model as your DB schema changes
- 11. How does DBRE work? • Uses the standard java.sql.DatabaseMetaData implementation of your JDK • Connects to a live database using JDBC and creates entities from the database metadata obtained • Similar to the output generated by the Eclipse wizard with all accepted defaults
- 12. Spring Roo DBRE Commands • database introspect --schema <name> [--file <name>] – Displays database metadata in XML format in the Roo shell – Optional --file <file name> saves metadata to specified file – Provides a preview of the mappings used in the final model
- 13. Spring Roo DBRE Commands • database reverse engineer [--schema <name>] [-- package <name>] – Creates entities in the specified package – --schema and --package options required only for first time run of command – Automatically generates type and field names from table and column names – JPA-annotated fields and getters/setters saved in AspectJ ITDs, eg Person_Roo_DbManaged.aj
- 14. Primary Keys • Supports single and composite primary keys – Creates a separate primary key class for tables having more than one primary key or no primary key (uses all fields for key) – Annotates the primary key class with @Embeddable and the entity's id with @EmbeddedId
- 15. Entity Relationships • Automatically creates and maintains bi-directional relationships: – @ManyToMany, many-valued associations with many-to- many multiplicity – @OneToOne, single-valued associations to other entities that have one-to-one multiplicity – @OneToMany, many-valued associations with one-to-many multiplicity – @ManyToOne, single-valued associations to other entities that have many-to-one multiplicity
- 16. DEMO Database Reverse Engineering Demo
- 17. Apache Solr / Lucene Integration
- 18. What is Apache Solr? • Search server • Built upon Apache Lucene (Java) • Fast, very • Scalable, query load and collection size • Distributed search and index replication • Interoperable • Extensible
- 19. Solr Features • Powerful full-text search • Hit highlighting • Faceted search • Spell checking • Dynamic clustering • Database integration • Rich document (e.g., Word, PDF) handling.
- 20. Interacting with Solr • HTTP GET / POST • JSON / XML • SolrJ (embedded over HTTP) • Ruby: solr-ruby, RSolr • many others: python, PHP, solrsharp, XSLT • JMX monitoring available • Admin interface available
- 21. Configuring Solr • schema.xml – Defines field types – Can drive more intelligent processing – Dynamic Fields enable on-the-fly addition of new fields – CopyField • indexing a single field multiple ways • combining multiple fields into a single searchable field – Many additional text analysis components • word splitting, • regex filters • sounds-like filters
- 22. Roo Solr Integration • Roo Shell – solr setup install SolrJ driver in project pom.xml – solr add make individual type searchable – solr all make all JPA entities searchable • @RooSolrSearchable type annotation • Hooks into JPA lifecycle – @PostPersist – @PostUpdate – @PreDelete • Uses SolrJ client
- 23. Entity Methods Introduced via Roo • QueryResponse search(String queryString) • QueryResponse search(SolrQuery query) • @Async void indexPerson(Person person) • @Async void indexPeople(Collection<Person> people) • @Async deleteIndex(Owner owner) • solrServer is also accessible on target type.
- 24. DEMO Apache Solr
- 26. Demand for Choice • ROO-301: Choose between data access patterns – demand for repository and DAO pattern support • 70+ votes in Spring Roo Jira, second most popular issue – Spring JDBC template – demand for iBatis support (ROO-452) – demand for NoSQL integration – demand for polyglot persistence
- 27. Hades Add-On • Have you heard of Hades project? – Utility library to work with Data Access Objects • implemented with Spring and JPA – Main goal is to ease the development and operation of a data access layer in applications • Installation in the Roo shell with a single command: – addon install --bundleSymbolicName org.synyx.hades.roo.addon – hades setup – hades repository --entity ~.domain.Person – more features planned (finders, DDD, etc)
- 29. Summary • Roo has deep and rich persistence support • Roo’s Incremental DBRE feature is the next generation in DBRE capabilities • Solr and Incremental DBRE offer devs a major productivity boost • Alternative persistence technologies supported and expanding