1. Custom Key Generator In Hibernate Mode
2. Custom Key Generator In Hibernate Key

Jan 25, 2015 In this post, we are going to learn how to create custom generator class in hibernate. Hibernate supports many built in generator classes like assigned, sequence, increment, identity, native etc. But some requirements these generator classes we can't use. Define the cache key at the class and method level. You can define the cache key at class and method level with the key and keyGenerator attributes of the @Cachable, @CachePut and @CacheEvict annotations. If key and keyGenerator are empty (by default), Spring Cache will use the SimpleKeyGenerator if no custom key generator implementations have. Oct 28, 2018  To use a sequence-based id, Hibernate provides the SequenceStyleGenerator class. This generator uses sequences if they're supported by our database, and switches to table generation if they aren't. To customize the sequence name, we can use the @GenericGenerator  annotation with SequenceStyleGenerator strategy. In hibernate generator class is used to generate unique identifiers for instances of persistence class. Hibernate provides you the list of default generator classes and of course they all have advantages and disadvantages.

Reference Guide

JPA 2 defines a new typesafe Criteria API which allows criteria queries to be constructed in a strongly-typed manner, using metamodel objects to provide type safety. For developers it is important that the task of the metamodel generation can be automated. Hibernate Static Metamodel Generator is an annotation processor based on the [Pluggable Annotation Processing API] with the task of creating JPA 2 static metamodel classes. The following example show two JPA 2 entities Order and Item, together with the metamodel class Order_ and a typesafe query.

The structure of the metamodel classes is described in the [JPA 2 Specification], but for completeness the definition is repeated in the following paragraphs. Feel free to skip ahead to Chapter 2, Usage if you are not interested into the gory details.

The annotation processor produces for every managed class in the persistence unit a metamodel class based on these rules:

• For each managed class X in package p, a metamodel class X_ in package p is created.

• The name of the metamodel class is derived from the name of the managed class by appending '_' to the name of the managed class.

• The metamodel class X_ must be annotated with the javax.persistence.StaticMetamodel annotation.

• If class X extends another class S, where S is the most derived managed class (i.e., entity or mapped superclass) extended by X, then class X_ must extend class S_, where S_ is the metamodel class created for S.

• For every persistent non-collection-valued attribute y declared by class X, where the type of y is Y, the metamodel class must contain a declaration as follows:

• For every persistent collection-valued attribute z declared by class X, where the element type of z is Z, the metamodel class must contain a declaration as follows:

  • if the collection type of z is java.util.Collection, then /microsoft-office-2010-professional-activation-key-generator.html.

  • if the collection type of z is java.util.Set, then

  • if the collection type of z is java.util.List, then

  • if the collection type of z is java.util.Map, then

    where K is the type of the key of the map in class X

Import statements must be included for the needed javax.persistence.metamodel types as appropriate and all classes X, Y, Z, and K.

The jar file for the annotation processor can be found in the JBoss Maven repository using Example 2.1, “Maven dependency ”.

Alternatively, a full distribution package can be downloaded from SourceForge.

In most cases the annotation processor will automatically run provided the processor jar is added to the classpath and a JDK 6 is used. This happens due to Java's Service Provider contract and the fact the the Hibernate Static Metamodel Generator jar files contains the file javax.annotation.processing.Processor in the META-INF/services directory. The fully qualified name of the processor itself is: org.hibernate.jpamodelgen.JPAMetaModelEntityProcessor.

Note

The use of a Java 6 compiler is a prerequisite.

As mentioned before, the annotation processor will run automatically each time the Java compiler is called, provided the jar file is on the classpath. Sometimes, however, it is useful to control the annotation processing in more detail, for example if you exclusively want to run the processor without compiling any other source files. Example 2.2, “Javac Task configuration” shows how Ant's Javac Task can be configured to just run annotation processing.

The option -proc:only instructs the compiler to just run the annotation processing. You can also completely disable processing by specifying -proc:none.

Tip

Custom Key Generator In Hibernate Mode

Run 'javac -help' to see which other annotation processor relevant options can be specified.

The maven-compiler-plugin approach has the disadvantage that the maven compiler plugin does currently not allow to specify multiple compiler arguments (MCOMPILER-62) and that messages from the Messenger API are suppressed (MCOMPILER-66). A better approach is to disable annotation processing for the compiler plugin as seen in Example 2.4, “Maven compiler plugin configuration - indirect execution”.

Once disabled, the maven-annotation-plugin for annotation processing (you will need the following additional maven repositories: maven-annotation-plugin and jfrog) can be used. The configuration can be seen in Example 2.5, “Configuration with maven-annotation-plugin”.

Netbeans support for annotation processors is at the time of this wrinting still in the making. Refer to NetBeans issues 111065, 111293 and 111294.

For further usage question or problems consult the Hibernate Forum. For bug reports use the METAGEN project in the Hibernate Jira instance. Feedback is always welcome. open office mac download yosemite

[Pluggable Annotation Processing API] JSR 269: Pluggable Annotation Processing API. Copyright © 2006 SUN MICROSYSTEMS, INC. <jsr-269-feedback@sun.com>JSR 269 JCP Page .

Custom Key Generator In Hibernate Key

[JPA 2 Specification] JSR 317: Java™ Persistence API, Version 2.0 . Java Persistence 2.0 Expert Group. . Copyright © 2009 SUN MICROSYSTEMS, INC. <jsr-317-feedback@sun.com>JSR 317 JCP Page .