Hibernate
Tools, Criteria API, Search, Shards
Martin Valkanov
Contents
1. Hibernate Tools
• Schema export, Entity model diagram
2. Criteria API
• Restrictions
• Find by example
• DetachedCriteria
• Projections
• Class property
Contents
3. Hibernate Projects
• Search
• Shards
Hibernate Tools
Ant tasks and IDE integration
Schema Export
• Use the Schema Export command line
tool to generate schema creation DDL:
java -cp ...
org.hibernate.tool.hbm2ddl.SchemaExport
--config=hibernate.cfg.xml
--text --create --output=schemaExport.sql
Schema Export
• Or use the Ant task:
Entity Model Diagram
• Use the hbm2doc Ant task and GraphViz:
Entity Model Diagram
• Or create a new Hibernate Configuration
in Eclipse, right-click on an entity and
choose „Open Mapping Diagram“
Criteria API
Building queries without clumsy
string manipulation
Restrictions
• Simple and powerful query building:
Criteria criteria =
session.createCriteria(PaymentModelImpl.class);
criteria.add(Restrictions.like("description",
"Комплект", MatchMode.START));
criteria.add(Restrictions.or(Restrictions.gt("amoun
t", new Long(200)),
Restrictions.like("description", "маса",
MatchMode.ANYWHERE)));
criteria.createCriteria("merchant").add(Restriction
s.eq("url", "http://www.mebeli-georgiev.com/"));
List result = criteria.list();
Find by Example
• A search prototype entity can be used to
model restrictions on the properties set:
PaymentModel example = new
OnlineShoppingModelImpl();
example.setDescription("шкаф");
Criteria criteria =
session.createCriteria(PaymentModelImpl.class);
criteria.add(Example.create(example).ignoreCase().e
nableLike(MatchMode.ANYWHERE));
List result = criteria.list();
Detached Criteria
• A detached criteria can be:
• serialized to a byte stream
• sent over the wire
DetachedCriteria dc =
DetachedCriteria.forClass(PaymentModelImpl.class);
dc.add(Restrictions.gt("amount", new Long(500)));
dc.add(Restrictions.eq("customer.id",
customer.getId()));
byte[] bytes = SerializationHelper.serialize(dc);
Detached Criteria
• and when restored – applied to another
Hibernate session:
DetachedCriteria dc = (DetachedCriteria)
SerializationHelper.deserialize(bytes);
List result =
dc.getExecutableCriteria(session).list();
Projections
• To do a group by query:
Criteria criteria =
session.createCriteria(PaymentModelImpl.class);
ProjectionList projectionList =
Projections.projectionList();
projectionList.add(Projections.rowCount(),
"count");
projectionList.add(Projections.sum("amount"),
"totalAmount");
projectionList.add(Projections.groupProperty("custo
mer"), "customer");
criteria.setProjection(projectionList);
criteria.setResultTransformer(Transformers.aliasToB
ean(CustomerPaymentInfo.class));
Class property
• Entity class can also be used in Criteria's
restrictions:
Criteria criteria =
session.createCriteria(PaymentModelImpl.class);
criteria.add(Restrictions.eq("class",
OnlineShoppingModelImpl.class));
Hibernate Projects
Unified data access programming style
Hibernate Search
• Integration with Apache Lucene indexing
• Indexed fields are annotated:
@Field(index=Index.TOKENIZED, store=Store.NO)
private String getDescription() {
///
}
• Index update is hooked via event
listeners: post-insert, post-update and
post-delete
Hibernate Search
• Access to Lucene API while benefitting
from the Hibernate Session:
String fullTextQuery = "description:(+\"кафяв
маса\"~3 +шкаф)";
FullTextSession fullTextSession =
Search.createFullTextSession(aSession);
QueryParser queryParser = new
QueryParser("description", new StandardAnalyzer());
Query query = fullTextSession.createFullTextQuery(
queryParser.parse(fullTextQuery),
PaymentModelImpl.class);
List result =
query.setMaxResults(50).list();
Hibernate Shards
• Application data is partitioned into
several data sources.
• Associated entities are stored in the same
shard.
• Custom SessionFactory and Session
implementation.
Hibernate Shards
• ShardStrategy
• ShardSelectionStrategy - Where to persist
a new entity
• ShardResolutionStrategy - Determine the
shards on which an object might live
• ShardAccessStrategy - Parallel,
Sequential, LoadBalancedSequential
Hibernate
Demos