Chicago, October 19 - 22, 2010

New Persistence Features in Spring Roo 1.1 Stefan Schmidt

Agenda

•  Spring Roo’s Approach to Persistence •  Incremental Database Reverse Engineering •  Apache Solr / Lucene Integration •  Alternative Persistence Technologies

Spring Roo’s Approach to Persistence

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

No DAOs?

•  No DAO layer by default –  Objections:

•  testing •  separation of concern •  pluggable implementations •  non JPA persistence •  security authorizations •  security auditing •  finders •  architectural reasons

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

Incremental Database Reverse Engineering

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

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

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

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

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

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

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

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

DEMO Database Reverse Engineering Demo

Apache Solr / Lucene Integration

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

Solr Features

•  Powerful full-text search •  Hit highlighting •  Faceted search •  Spell checking •  Dynamic clustering •  Database integration •  Rich document (e.g., Word, PDF) handling.

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

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

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

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.

DEMO Apache Solr

Alternative Persistence Technologies

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

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)

DEMO Hades Add-On

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