An extension for Speedment that make it possible to react to changes in a database and creating Materialized Object Views.
The extension consists of two classes. The Reactor polls the database at a regular interval, downloading modifications to one specific table in batches. The changes are then parsed so that a set of listeners can act on them. The second class is the MaterializedView class. It can act as a listener on a Reactor, merging the changes into one materialized view. That view can then be queried to get a current state of the database without causing additional statements to be sent.
To add reactivity to your Speedment project, simply add the following dependency to your pom.xml-file:
<dependency>
<groupId>com.github.pyknic</groupId>
<artifactId>reactor</artifactId>
<version>1.0.1</version>
</dependency>To set up a materialized view of a table article_event, do the following once (after initiating Speedment):
final MaterializedView<ArticleEvent> articlesView
= new MaterializedView<>(ArticleEvent.ARTICLE_ID);
final Reactor<ArticleEvent> reactor =
Reactor.builder(speedment.managerOf(ArticleEvent.class), ArticleEvent.ARTICLE_ID)
.withListener(articlesView)
.build(); // Automatically starts the reactorA materialized view must always have a particular field that events should be merged on. This is different than the primary key. Rows that have the same value of this field, in this case ARTICLE_ID, will be considered the same entity and will be merged in the view.
This project is made available under the Apache 2 license.