[CONF] Apache Cayenne Documentation > Guide to 3.0 Features

[confluence]

Guide to 3.0 Features Page edited by Andrus Adamchik This page highlights the new features and changes introduced in 3.0 release, roughly corresponding to the latest released milestone. It is a high level overview and as such is by no means complete. Consult RELEASE-NOTES.txt file included in each release for the full list of changes. Distribution Contents Structure Cayenne JPA Provider Object Relational Mapping Cayenne Persistence API Remote Object Persistence CayenneModeler Deployment and Runtime Tools Distribution Contents Structure There are a few changes in the contents of the distribution "lib" folder. For details see this page. Main Cayenne JAR is now called "cayenne-server-x.x.x.jar". We no longer ship the "fat" jar with dependencies. Instead dependencies are included in the separate jars in "lib/third-party" distribution folder. CayenneModeler is located in the "bin" folder. Never mind the "lib/cayenne-modeler-x.x.x.jar" - this is just an underlying Modeler library, used in "local JNDI" configuration for instance, not the runnable application. Cayenne JPA Provider Note that Cayenne JPA provider work has been frozen and it IS NOT included in 3.0. If you have further questions or would like to give a hand with the JPA work, please send a note to developer mailing list. Object Relational Mapping Killed DerivedDbEntity Concept Stopped supporting DerivedDbEntity - its functionality (aggregate queries) is achieved via EJBQL and other means. DataMap DTD Replaced with Schema A schema is now available here for the DataMap XML format. Embeddables (as of M6 there's no Modeler support) Added a new mapping artifact - Embeddable, that allows to map composite objects to a single table. Flattened Attributes (as of M6 there's no Modeler support) Just like with "flattened" relationships, now there is a way to map an ObjAttribute that spans one or more DbRelationships and is mapped to a column of a joined table. Persisting Primitives and a Number of Other Simple Properties DataObjects are now allowed to have primitive properties, such as int, boolean, etc. Also Cayenne can now persist the following extra simple property types: java.util.Calendar, java.math.BigInteger, java.io.Serializable, char[], java.lang.Character, java.lang.Character[], java.lang.Byte[]. Support for To-Many Relationship Maps and Collections. In addition to mapping a to-many relationship as a List, Cayenne now supports to-many Maps (keyed by target object pk, or an arbitrary unique property), Sets and generic Collections. Note that relationship maps is the only conceptually new type of relationships. Collection and Set are not that different from the earlier List behavior (that was a Collection, and just like Set ensured uniqueness of its objects). Support for "extended" Enums Mapping In addition to vanilla Java enums, Cayenne allows enums to provide a custom database value for each enumerated instance by implementing org.apache.cayenne.ExtendedEnumeration. This way a persistent value doesn't have to be tied to the enum Java name or position. DbAttribute Scale and Precision Changed DbAttribute "precision" property to "scale" (as it meant scale all along) and added a separate "precision" attribute to track precision. Cayenne Persistence API Java 5 Migration Cayenne now requires Java 5 or newer to run. This allowed us to start using generics, enums and other Java 5 features. ObjectContext While you can still use DataContext directly, we encourage you to avoid direct dependency on DataContext throughout your code, and instead use org.apache.cayenne.ObjectContext interface. E.g.: ObjectContext context = DataContext.createDataContext(); This protects your code from the evolution of the underlying implementation, allows you to customize context behavior by using interface wrappers. There are plans to update all Cayenne API to return ObjectContext everywhere DataContext might be returned. EJB QL Queries Never mind the "EJB" in the name. EJBQL queries are a powerful object query mechanism similar to the one supported by the JPA specification. EJBQLQuery is a first-class citizen, just like SelectQuery. SQLTemplate Query Improvements Significantly simplified the process for fetching DataObjects (vs. DataRows) via a SQLTemplate query with 'setColumnNamesCapitalization' method. Added support for fetching scalar and mixed scalar/object results using SQLResultSetMapping. Entity Lifecycle Callbacks Cayenne lifecycle callbacks are similar to callbacks defined in the JPA specification. This is a feature that allows to perform custom operations at certain points in the object lifecycle. For more details see this page. General Query Improvements Added support for fetch offset (complimentary to the existing "fetch limit"). DataContext Changes Implemented DataContext.rollbackChangesLocally(). This was missing in 2.0, limiting the operation of the nested DataContexts. Cache Management pluggable query cache a notion of Query cache groups automated cache key management for standard queries _expression_ Improvements Added missing DB expressions to ExpressionFactory. Added support for OUTER JOINS Added support for matching against TRUE and FALSE. Database Integration Changes/Improvements Added support for "long" primary keys (vs. "int" PK used previously) Added adapter for SQLite database. Added adapter for H2 database. Added stored procedure support on MySQL. Changed default table type on MySQL to InnoDB, added MySQL FK constraints support in the Modeler. Turned on update query batching on SQL Server and Derby. Class Generation Improvements Generating classes for DataMaps that contain type-safe methods for all mapped SelectQueries. Prefetching Improvements Joint prefetches are switched to OUTER joins, removing the major limitation to their use. Disjoint to-many prefetches no longer have a limitation preventing their use if a query qualifier spanned prefetched relationships. POJO Persistence (status: experimental. Unlikely to be production ready in 3.0) Remote Object Persistence Validation callbacks support for ROP ObjectContext Now object validation works the same way on the ROP client as it did on the server. Nested contexts support for ROP ObjectContext Nested contexts can now be created for ROP contexts. Creation method is added to ObjectContext interface. CayenneModeler The Modeler underwent significant changes with the goal to improve usability and look-and-feel. Added copy/paste support Reworked ObjRelationship mapping dialog Added combo auto-completion Added a usable and good looking welcome screen Added contextual menus Added detection of project file changes on disk Added multi-item selection Added ability to specify password encryption mechanism Added ability to drag and drop cayenne.xml from the filesystem to the Modeler window to open the project. Added support for to-many relationship collections mapping. Added "search" functionality Added lifecycle callback and listener mapping functionality. Added support for merging DataMap changes back to the database. Removed support for DerivedDbEntity Added confirmation dialog for delete actions Reopen Last Project on Startup Added progress/log view Added SQL syntax highlighting. Added EJBQL Query mapping capabilities, with synatx highlighting. Added support for quoting of SQL Identifiers The Modeler can be started from Maven Deployment and Runtime Improved Performance Paginated query algorithm is changed, resulting in very significant performance improvements on large data sets (this also improves ROP paginated query performance). This includes faster query times and much smaller memory footprint of an unresolved list. Reduced the scope of lock on a shared cache during commit, that should result in improved concurrency. Queries using disjoint to-many and joint to-one prefetching now work significantly faster. ROP new context creation speed is improved, as EntityResolver is cached on the client after first retrieval. ROP uses a "diff compression" algorithm on commit, reducing the amount of data passed around. Improved Memory Management Leak free ObjectContext Query lists are cached in an LRU map, so there's no indefinite memory growth when using query caching. Logging Switched to commons-logging from Log4J Cayenne no longer has a Log4J dependency. Instead it uses Jakarta commons-logging, as described here. Note that 2.0 Log4J configurations should continue to work, although now it is a user responsibility to bootstrap Log4J - Cayenne will no longer do it for you. E.g. you can do this on startup: org.apache.log4j.PropertyConfigurator.configure("cayenne-log.properties"); Optional Quoting of SQL Identifiers Cayenne now supports optional quoting of SQL identifiers in the generated SQL. This has been a very popular request in the past. Identifier quoting can be turned on per DataMap in the Modeler (look for "Quote SQL Identifiers" checkbox). This will allow to map column names that contain spaces, non-ascii characters, reserved words, etc., i.e. the schemas that could not be mapped with Cayenne before. Ability to Detect Missing/Partial Schema and Auto Generate Schema in Runtime (status: as of M6 column consistency checks) DataNode has a new attribute in the Modeler - "Schema Update Strategy". This allows to specify runtime behavior in regards to schema consistency checking. The default behavior is "do nothing" (org.apache.cayenne.access.dbsync.SkipSchemaUpdateStrategy). Alternatively Cayenne can create the schema if none is found or throw an exception if schema inconsistencies are detected. Tools Switched "cgen" to "version 1.2" of the template as a default version Support for classpath in "cdbgen". The Modeler can be started from Maven, that can potentially help in aligning the Modeler version with the project runtime Cayenne version. Change Notification Preferences View Online | View Change | Add Comment