Group items tagged

"I've had an opportunity recently to work on a product that needed an RIA web interface, and I chose my recent favorite tool for this, Vaadin. The services for this project needed to be highly scalable, and lent themselves well to functional techniques, so I selected Scala as my language of choice. I build my projects with Maven, for reasons I won't go into right now, and I do much of my JVM-language work in Intellij's excellent IDEA IDE. Given these tools, I found a way to facilitate very rapid development of web UI's, and I thought I'd pass it along. Another technique I use, which I'll expound on later, is creating "dummy" implementations of all of my backing services for my application. The "real" implementations are written as OSGi services, in separate modules from my UI. The UI is packaged as a war, but is also OSGi aware, with a bundle activator. This activator only gets called if the war is deployed into an OSGi container, and not otherwise. This allows the app to select which implementation of the services it uses - the "dummy" ones when it's deployed outside of OSGi, and the "real" ones when they're available. This means I can use the handy Maven jetty plugin to quickly spin up my application and test it on my local workstation, without needing all of the dependencies (like a data store and such) of my real services. That's good, in that I can get my "cycle time" down to a few seconds, where "cycle time" is the time between making a change and actually being able to test it in my browser. We can do better, though. I'm using Scala as my language of choice for building the UI as well, as it works just fine with Vaadin (and with everything else in the JVM ecosystem, for that matter, which is why I didn't choose a non-JVM language - but that's yet another rant). I compile my Scala with the Maven scala plugin - here's where the next handy bit comes into play. Turns out the Scala plugin has a goal cal

"Besides a rich user interaction many applications need to display a big amount of data sets as diagrams or reports as part of their applications. In order to bridge the gap the BIRT project was created as part of the eclipse ecosystem. BIRT is an open source Eclipse-based reporting system that integrates with your Java/J2EE application to produce compelling reports. That BIRT integrates well with classic RCP applications is a well known fact. But the need for rich internet applications is still growing. And here the RAP comes into play. As a platform for developing Web 2.0 applications with the same patterns as for RCP it paves the way for single sourcing applications running on both platforms. In this talk we will show how to integrate diagrams and reports known from BIRT into RAP applications. Topics covered include how to setup the environment to let BIRT and RAP play well together. In addition we will give advices how to use the reports inside RAP applications and which problems may arise. As a final outcome of we will know everything to bring reporting capabilities into RAP applications. "

UNICASE is a CASE-Tool integrating models from the different development acitivities, such as requirements, use cases, UML models, schedules, bug and feature models into a unified model. This unified model is highly traceable by design. The UNICASE client allows to view and edit these models in a textual, tabular and diagram visualization. The models are stored and versioned on a server comparable to svn but customized for models. Client and server are easily extensible to support integrating new models into the unified model. UNICASE is based on the Eclipse platform including EMF and GMF. It can also be used as a framework to build modeling applications that reuse its repository and visualization capabilities. The project is open-source and released under the Eclipse Public License v 1.0 (EPL). It builds on our experience from the Sysiphus project in building a CASE tool.

JAXB stands for Java Architecture for XML Binding. It provides mechanism to marshal (write) java objects into XML and unmarshal (read) XML into object. Simply, you can say it is used to convert java object into xml and vice-versa.

We are group of passionate programmers, who would like to help the interested students learn the art of programming. At Merit Campus, we are trying to bring all the programing related information into one place. Here you can read the topics, watch videos, answer questions, write programs, track your progress, compare with other students and finally publish your skills or include it in your resume

Dart is an open-source, general-purpose, class-based, object-oriented language with C-style syntax which can optionally transcompile into JavaScript. It...

" Why Object Teams? Team spirit for your objects Building complex systems from isolated objects often yields poor structure which readily decays during system evolution. Objects should team-up in order to co-operate and jointly deliver complex behaviors. Objects play specific roles within a given Team. Context based dispatch Role instances are attached as specializers to existing objects. Object behavior is controlled by the currently active context that determines which roles are active at a given point in time. Contexts are reified into team instances, which may further be used to mediate between roles and maintain state of the collaboration. Modules larger than classes On the road to re-use of modules larger than classes two approaches compete: frameworks and components. For many applications white box frameworks are too fragile and black box components to rigid. Object Teams provide a middle road which balances encapsulation and adaptability. "

Besides being able to query and manipulate the underlying data management system with Blueprints, a GraphML reader and writer package is provided with Blueprints for streaming XML graph representations into and out of the underlying graph framework. The GraphML package uses StAX to process a GraphML graph. This section discusses the use of the GraphML library for reading and writing XML-encoded graphs.

Setting up an infrastructure for Instant Messaging" article series. In my previous tutorials, I showed you how to setup the Openfire IM Server and how to configure the Spark client in order to connect to that server. In this tutorial, I will show you how to add XMPP messaging capabilities to your own application. I will use the Smack library, an Open Source XMPP (Jabber) client library for instant messaging and presence. Smack is a pure Java library and can be embedded into your applications to create anything from a full XMPP client to simple XMPP integrations.

DdlUtils is a small, easy-to-use component for working with Database Definition (DDL) files. These are XML files that contain the definition of a database schema, e.g. tables and columns. These files can be fed into DdlUtils via its Ant task or programmatically in order to create the corresponding database or alter it so that it corresponds to the DDL. Likewise, DdlUtils can generate a DDL file for an existing database. DdlUtils uses the Turbine XML format, which is shared by Torque and OJB. This format expresses the database schema in a database-independent way by using JDBC datatypes instead of raw SQL datatypes which are inherently database specific. An example of such a file is:

A few weeks back, I wrote a blog entry lamenting the attitude toward IDEs in the Scala community. A few people told me that the tooling situation was better than I'd implied, so I thought I'd spend a bit of time looking at using Scala (and Lift specifically) in Eclipse. I think the situation is still a ways away from the tooling situation for Java, but it is actually quite good, and I wanted to post a quick tutorial for those interested in developing Lift in Eclipse. Prerequisites This post assumes that you already have Scala 2.8 final and Eclipse 3.6 on your system. For Eclipse, I recommend upping the Xmx setting if you haven't already - I had issues when I had multiple Lift projects imported with Xmx set to 386. Also, this tutorial is going to use Maven, not SBT. SBT may be a better build tool for Scala projects, but I'm not sure how well it works with m2eclipse - I'm going to play with that more later. I also assume you know how to install plugins into Eclipse - I will create a more in-depth screencast for doing all of this if there is enough interest.

"Logback is intended as a successor to the popular log4j project, picking up where log4j leaves off. Logback's basic architecture is sufficiently generic so as to apply under different circumstances. At present time, logback is divided into three modules, logback-core, logback-classic and logback-access. The logback-core module lays the groundwork for the other two modules. The logback-classic module can be assimilated to a significantly improved version of log4j. Moreover, logback-classic natively implements the SLF4J API so that you can readily switch back and forth between logback and other logging frameworks such as log4j or java.util.logging (JUL). The logback-access module integrates with Servlet containers, such as Tomcat and Jetty, to provide HTTP-access log functionality. Note that you could easily build your own module on top of logback-core. "

The release 3.0 of Spring Framework added the Spring Module OXM which supports the marshalling and unmarshalling of Java objects and XML documents.In this post, we will be using Spring OXM to take a Java object, convert it to a XML-format and save it in the hard-disk as an XML file containing information of that Java object. We will also cover how to retrieve back the serialized state of that XML file and reconstruct it back to it's original state as a Java object.

Sample of using Hibernate Annotations by reducing XML configuration files thus making it simpler to define required metadata directly into our Java code. When using annotations, we no longer need the additional mapping file (*.hbm.xml). The metadata for the ORM is specified in the individual classes.

Mod4j (Modeling for Java) is an open source DSL-based environment for developing administrative enterprise applications. It uses a collection of DSL's to model different parts of the architecture, combined with manually written code. Currently Mod4j consists of four DSLs: the Business Domain DSL, Service DSL, Data Contract DSL and Presentation DSL. The modeling environment is seamlessly integrated into the Eclipse IDE which gives the developers one environment where they can easily switch back- and forth between models and code. The different DSL?s used in Mod4j can be used independently, but if they are used in collaboration they will be fully validated with each other. Apart from integration in the Eclipse IDE, Mod4j also supports the use of Maven. That is, using the DSL models as the source, the complete code generation process can be run automatically on a build server without the need for Eclipse. The Mod4j DSLs and the corresponding code generators are based on a reference architecture. This allows developers to model various aspects of the application and generate code that strictly follows this reference architecture. The reference architecture is described in a separate document. For a good understanding of the generated code it is useful to read this document.

Provide mechanisms for integrating Java security providers into Eclipse: Applications that need to implement security related functionality require cryptographic services upon which to build. Java provides the Java Cryptography Architecture (JCA) as a mechanism for installing implementations of several interfaces used for cryptography, including MessageDigest, Signature, KeyStore, Certstore, and more. In a typical Java application, these implementations reside in the extensions directory of the JRE. In a dynamic Eclipse application, the appropriate packaging mechanism is in Eclipse plug-ins. The goal is to allow JCA to be used in an Eclipse environment while maintaining the programming model of the JCA subsystem. A related goal is to expose the configuration of the JCA system via an Eclipse-based user interface, allowing authorized users to inspect and modify the Security object.

"At this point, the only source of useful overview documentation for the Common Navigator are the excellent tutorials at Michael Elder's (the author of the CN) blog. Soon I hope to get some of this transferred into the Eclipse Plugin Developer's Guide. RCP applications can quickly and easily use the CN to show the resources in the workspace. This assumes that your RCP application uses resources (which is another discussion). The CN can also be used for non-resource RCP applications, in that case, these instructions don't apply, as the objects treated by the CN have to be created directly by the RCP application. If you are planning to use the CN in an RCP application that uses resources, there are 3 (2 of which are completely undocumented) things you must do:"

So I started with a maven web application in Eclipse to do my test drive of jersey. I added the repositories, and the jersey-server dependency (https://jersey.dev.java.net/source/browse/*checkout*/jersey/tags/jersey-1.0.2/jersey/dependencies.html) I started out with a filter, instead of the servlet. I always prefer filters. I also added the following initialization parameters:

There are many approaches available to scale PostgreSQL beyond running on a single server. An outline of the terminology and basic technologies involved is at High Availability and Load Balancing. There is a presentation covering some of these solutions. There is no one-size fits all replication software. You have to understand your requirements and how various approaches fit into that. For example, here are two extremes in the replication problem space: You have a few servers connected to a local network you want to always keep current for failover and load-balancing purposes. Here you would be considering solutions that are synchronous, eager, and therefore conflict-free. Your users take a local copy of the database with them on laptops when they leave the office, make changes while they are away, and need to merge those with the main database when they return. Here you'd want an asynchronous, lazy replication approach, and will be forced to consider how to handle conflicts in cases where the same record has been modified both on the master server and on a local copy. These are both database replication problems, but the best way to solve them is very different. And as you can see from these examples, replication has a lot of specific terminology that you'll have to understand to figure out what class of solution makes sense for your requirements. A great source for this background is in the Postgres-R Terms and Definitions for Database Replication. The main theoretical topic it doesn't mention is how to resolve conflict resolution in lazy replication cases like the laptop situation, which involves voting and similar schemes.

" Registered 2008-09-26 by Michael Terry Déjà Dup is a simple backup tool. It hides the complexity of backing up the Right Way (encrypted, off-site, and regular) and uses duplicity as the backend. Features: * Support for local, remote, or cloud backup locations, such as Amazon S3 or Rackspace Cloud Files * Securely encrypts and compresses your data * Incrementally backs up, letting you restore from any particular backup * Schedules regular backups * Integrates well into your GNOME desktop For Ubuntu users, there are three ways to get Déjà Dup: * Supported releases: http://apt.ubuntu.com/p/deja-dup * Stable release backports: https://launchpad.net/~deja-dup-team/+archive/ppa * Daily builds: https://launchpad.net/~deja-dup-team/+archive/testing If you are interested in contributing, there are many ways to help: * http://live.gnome.org/DejaDup/GettingInvolved"