Posts Tagged ‘jpa’

Java EE 7 Database Migrations with Liquibase and WildFly

Thursday, July 31st, 2014

I have written about other database migration frameworks before but in this article I’d like to cover the Liquibase framework in combination with WildFly as Java EE 7 compatible application server.

In the following tutorial, we’re going to write a full Java EE 7 book store application with a few steps and with Liquibase on board to create the database structure and insert example data into the database.

Thanks to the WildFly Maven Plug-in we even do not need to download and configure the application server but let Maven and the plug-in do the work for us.

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Java Persistence API: Controlling the Second-Level-Cache

Monday, April 21st, 2014

Using the Java Persistence API and a decent persistence provider allows us to configure and fine-tune when and how the second level cache is used in our application.

In the following short examples, we’re going to demonstrate those features written as JUnit test cases and running on a H2 in-memory database.

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Creating elegant, typesafe Queries for JPA, mongoDB/Morphia and Lucene using Querydsl

Thursday, February 13th, 2014

Querydsl is a framework that allows us to create elegant, type-safe queries for a variety of different data-sources like Java Persistence API (JPA) entities, Java Data Objects (JDO), mongoDB with Morphia, SQL, Hibernate Search up to Lucene.

In the following tutorial we’re implementing example queries for different environments – Java Persistence API compared with a JPQL and a criteria API query, mongoDB with Morphia and last but not least for Lucene.

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Arquillian Transaction Extension: Transaction Rollback for your Java EE Integration Tests

Sunday, June 16th, 2013

I really love Arquillian to run integration tests for my Java EE applications – especially when running on different containers – and I also love the Arquillian tool stack from Arquillian Drone to the Arquillian Persistence Extensions.

Today I’d like to share a short snippet how to achieve transaction rollbacks when testing an EJB in combination with Arquillian and the Arquillian Transaction Extension…

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Creating slim Database Projections using JPA2 Constructor Expressions

Sunday, April 14th, 2013

One common question that you may encounter one day when using object-relational-mapping in your application is how to slim down data that you’re retrieving from the persistence layer down to a specific subset for your use-case in an efficient manner and without using complex additional mapping frameworks. In some situations you might declare lazy loaded fields but another approach that I’d like to share with you here are JPA2 constructor expressions.

Constructor expressions allow us to create plain old java objects from the result of an JPA query. The advantage is that we may use different projections for different scenarios and without being managed, the POJOs might help us save some resources here.

In the following tutorial, we’re going to persist 100 book entities with multiple properties to an embedded database and we’re using constructor expressions afterwards to create smaller POJOs using a subset of the information available from each persisted book.

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Adding multiple EntityListeners to an Entity in JPA 2

Monday, February 25th, 2013

The ability to attach lifecycle events to an entity using simple annotations sometimes is a neat feature in the Java Persistence API.

The following short snippets demonstrate how to bind and trigger the different available lifecycle events using an embedded derby database and a bunch of annotations.

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Arquillian Tutorial: Writing Java EE 6 Integration Tests and more..

Thursday, April 26th, 2012

Now that the long awaited stable version of the Arquillian framework is released I wanted to demonstrate some interesting features of  this framework that really eases writing and running of integration tests for Java EE 6 applications in many different ways.

In the following tutorial we are going to create some real-world examples using Enterprise JavaBeans, Contexts and Dependency Injection, the Java Persistence API and we’re finally running Drone/Selenium tests against a JEE Web Application that is using Java Server Faces.

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Hibernate Search Faceting: Discrete and Range Faceting by Example

Monday, March 26th, 2012

In today’s tutorial we’re exploring the world of faceted searches like the one we’re used to see when we’re searching for an item on Amazon.com or other websites. We’re using Hibernate Search here that offers an API to perform discrete as well as range faceted searches on our persisted data.

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JPA Persistence and Lucene Indexing combined in Hibernate Search

Sunday, February 5th, 2012

Often we’re writing an application that has to handle entities that – on the one side need to be persisted in a relational database using standards like the Java Persistence API (JPA) and using frameworks like Hibernate ORM or EclipseLink.

On the other side those entities and their fields are often stored in a highspeed indexer like Lucene. From this situation arises a bunch of common problems .. to synchronize both data sources, to handle special data mapped in an entity like an office document and so on..

Hibernate Search makes this all a lot easier for us as we’re hopefully going to see in the following short tutorial…

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Bean Validation with JSR-303 and Hibernate Validator

Tuesday, December 14th, 2010

You want to add some validation logic to your Java beans? You want to achieve this with some shiny extendable annotations? Then give the Java Bean Validation standard aka JSR-303 a try..

We’re going to use the reference implementation for bean validation, Hibernate Validator in this tutorial but there are also links to other alternatives like Oval or Apache Bean Validation.

So let’s begin and validate some stuff ..
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Object-relational Mapping using Java Persistence API / JPA 2

Monday, October 11th, 2010

Today we’re going to take a look at the world of object-relational Mapping and how it is done using the Java Persistence API by creating some basic examples, mapping some relations and querying objects using JPQL or the Criteria API..

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