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kuni katsuya

Lazy Loading with Flex, BlazeDS and Hibernate | RIA Zone - 0 views

ria.dzone.com/...loading-flex-blazeds-hibernate

flex blazeds hibernate lazy-loading

shared by kuni katsuya on 15 May 12 - No Cached
  • Lazy Loading with Flex, BlazeDS and Hibernate
  • By using dpHibernate and lazy loading, none of this extra work is required
  • proxies are sent initially for collections and complex objects, and fetched on-demand when requested by the client
  • ...2 more annotations...
  • Note that dpHibernate doesn't depend on Spring
  • entity classes must implement the org.dphibernate.core.IHibernateProxy interface, both on the Java and Actionscript classes
kuni katsuya

Chapter 15. Data Management - 1 views

www.graniteds.org/...graniteds.datamanagement.html

graniteds tide DataManagement

shared by kuni katsuya on 23 Apr 13 - No Cached
  •  abstractEntity.uid();
    • kuni katsuya
      kuni katsuya on 23 Apr 13
       
      sets the uid before persist
  •  UUID.randomUUID().toString();
  • AbstractEntity 
  • ...70 more annotations...
  • @MappedSuperclass
  • Important things on ID/UID
  • entity lives in three layers:
  • Flex client
  • JPA persistence context
  • database
  • When updating existing entities coming from the database
  • id is defined and is maintained in the three layers during the different serialization/persistence operations
  • when a new entity is being created in any of the two upper layers (Flex/JPA)
  • new entity has no id until it has been persisted to the database
  • most common solution is to
  • have a second persisted id, the uid
  • which is created by the client and persisted along with the entity
  • recommended approach to avoid any kind of subtle problems is to have a real uid property which will be persisted in the database but is not a primary key for efficiency concerns
  • You can now ask Tide to
  • limit the object graph before sending it
  • Flex with the following API :
  • EntityGraphUnintializer
  • uninitializeEntityGraph
  • Person object will be uninitialized
  • uperson contains
  • only the minimum of data
  • to correctly merge your changes in the server persistence context
  • Tide uses the
  • client data tracking
  • to determine which parts of the graph need to be sent
  • Calling the EntityGraphUninitializer manually is a bit tedious and ugly, so there is a cleaner possibility when you are using generated typesafe service proxies
  • annotate your service method arguments with @org.granite.tide.data.Lazy :
  • @Lazy
  • take care that you have added the [Lazy] annotation to your Flex metadata compilation configuration
  • in the Flex application, register the UninitializeArgumentPreprocessor component in Tide as follows :
  • [UninitializeArgumentPreprocessor]
  • all calls to PersonService.save() will
  • automatically use a properly uninitialized version
  • of the person argument.
  • 15.4. Dirty Checking and Conflict Handling
  • simplify the handling of data between Flex and Java EE
  • Chapter 15. Data Management
  • Tide maintains a client-side cache of entity instances and ensures that every instance is unique in the Flex client context
  •  uid().hashCode();
  • Tide currently only supports Integer or Long version fields, not timestamps and that the field must be nullable
  • in a multi-tier environment (@Version annotation)
  • highly recommended to use
  • JPA optimistic locking
  • highly recommended to add a
  • persistent uid field
  • AbstractEntity
  • in general this identifier will be
  • initialized from Flex
  • @Column(name="ENTITY_UID", unique=true, nullable=false, updatable=false, length=36)     private String uid;
  • @Version     private Integer version;
  • uid().equals(((AbstractEntity)o).uid())
  • consistent identifier through all application layers
  • @PrePersist
  • 15.3. Reverse Lazy Loading
  • 15.4. Dirty Checking and Conflict Handling
  • 15.4. Dirty Checking and Conflict Handling
  • 15.4. Dirty Checking and Conflict Handling
  • Dirty Checking and Conflict Handling
  • entity instance can be in two states :
  • Stable
  • Dirty
  • property meta_dirty is
  • bindable
  • could be used
  • to enable/disable a Save button
  • correct way of knowing if any object has been changed in the context, is to use the property meta_dirty of the Tide context
  • tideContext.meta_dirty
  • reliable when using optimistic locking
  • check that its @Version field has been incremented
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