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"MultiTail lets you view one or multiple files like the original tail program. The difference is that it creates multiple windows on your console (with ncurses). It can also monitor wildcards: if another file matching the wildcard has a more recent modification date, it will automatically switch to that file. That way you can, for example, monitor a complete directory of files. Merging of 2 or even more logfiles is possible. It can also use colors while displaying the logfiles (through regular expressions), for faster recognition of what is important and what not. It can also filter lines (again with regular expressions). It has interactive menus for editing given regular expressions and deleting and adding windows. One can also have windows with the output of shell scripts and other software. When viewing the output of external software, MultiTail can mimic the functionality of tools like 'watch' and such."

Vaadin is a Rapid Application Development (RAD) framework for RIA applications. I only know it for a few months but since I started experimenting with it, I'm really in favor of it. I see a lot of advantages compared to Sun's Java EE standard front-end framework JSF. First of all Vaadin is a java library, so you only have to write Java to build a complete frontend. No need for a specific frontend language, no need for converters (for comboboxes),… This also implies that you can use the full Java power on the frontend side and that's an huge advantage because frontend code is now type-safe and easily refactorable. You can unit test your frontend with JUnit. You can also use all existing java libraries on the frontend side, for example LOG4J. Another advantage is the fact that Vaadin is easy to learn (JSF isn't!) and to use: it's straigtforward. It feels like developing desktop apps and for me developing desktop apps feels much more intuitive than developing web-apps the way I'm used to. Vaadin uses convention over configuration. No need to register new components, validators or whatever in different xml files. Themes have a default folder and a default folder structure. Vaadin is very well documented. There's the book of Vaadin wich explains every aspect of the framework very clear. On the site there's a blog, a FAQ section, a wiki, a forum, examples with Java source code, … It's very easy to extend. Want to create your own Validator? Just implement an interface or extend another Validator and use it. Want to create your own custom server side component? Just extend the CustomComponent class or extend from another component. There's also an add-on directory where you can download UI components, data components, tools, themes, …

"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

"Contributed and administered by ICEsoft Technologies Inc., ICEpdf.org is a place where enterprise Java developers can learn, share, and contribute information and ideas to a growing community of ICEpdf developers. ICEpdf is an open source Java PDF engine that can render, convert, or extract PDF content within any Java application or on a Web server. ICEpdf.org provides a range of development and support resources to benefit all ICEpdf developers. Source code and application reference implementations are available for download here. Numerous reference implementations and examples are available to enable rapid learning and successful use of the product. The reference implementations are commercial quality implementations that can be deployed as-is, customized to meet specific requirements, or used as learning aids on how to use various features. Visit the ICEpdf demos page to see ICEpdf in action and to evaluate the capabilities of ICEpdf as a Java PDF viewer or deployed as servlet a headless server engine. Remember that ICEpdf is completely customizable and and can be completely embedded in your Java application. We invite you to join the ICEpdf community and to participate in the user forums. The resources available here and on the ICEpdf forums will get you up and developing that much quicker. "

"Community Dashboard Framework (CDF) is a project that allows you to create friendly, powerful, fully featured dashboards on top of the Pentaho BI server. Former Pentaho dashboards had several drawbacks from a developer's point of view. The developing process was awkward, it required know-how of web technologies and programming languages, and basically it was time-consuming. CDF emerged as a need for a framework that overcame all those difficulties. The final result is a powerful framework featuring the following: . It is based on Open Source technologies. . It separates logic (JavaScript) of the presentation (HTML, CSS) . It features a life cycle with components interacting with each other . It uses AJAX . It is extensible, which gives the users a high level of customization: . Advanced users can extend the library of components. . They also can insert their own snippets of JavaScript and jQuery code. CDF can be used: . As part of a Pentaho solution. This is the most common scenario. . In a standalone mode as an alternative to the Pentaho User Console . Integrated with Portlets, PHP applications, intranet portals and even desktop applications. "

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.

Xtext - Language Development Framework With Xtext you can easily create your own programming languages and domain-specific languages (DSLs). The framework supports the development of language infrastructures including compilers and interpreters as well as full blown Eclipse-based IDE integration. While Xtext equips you with a set of sensible defaults, you can tweak every single aspect of your language with Xtext's powerful APIs. A comprehensive documentation as well as the vivid community will help you getting started in no time. And if that is not enough you can buy trainings, consulting or support contracts delivered directly by the committers.

ModeShape (formerly "JBoss DNA") is a JCR 2.0 (JSR-283) implementation that provides access to content stored in many different kinds of systems. A ModeShape repository isn't yet another silo of isolated information, but rather it's a JCR view of the information you already have in your environment: files systems, databases, other repositories, services, applications, etc. To your applications, ModeShape looks and behaves like a regular JCR repository. Using the standard JCR API, applications can search, navigate, version, and listen for changes in the content. But under the covers, ModeShape gets its content by federating multiple back-end systems (like databases, services, other repositories, etc.), allowing those systems to continue "owning" the information while ensuring the unified repository stays up-to-date and in sync. ModeShape repositories can be used in a variety of applications. One of the most obvious ones is in provisioning and management, where it's critical to understand and keep track of the metadata for models, database, services, components, applications, clusters, machines, and other systems used in an enterprise. Governance takes that a step farther, by also tracking the policies and expectations against which performance can be verified. In these cases, a repository is an excellent mechanism for managing this complex and highly-varied information. But a ModeShape repository doesn't have to be large and complex: it could just manage configuration information for an application, or it could just provide a JCR interface on top of a couple of non-JCR systems.

"m2eclipse provides comprehensive Maven integration for Eclipse. You can use m2eclipse to manage both simple and multi-module Maven projects, execute Maven builds via the Eclipse interface, and interact with Maven repositories. m2eclipse makes development easier by integrating data from a project's Object Model with Eclipse IDE features. With m2eclipse, you can use Maven within Eclipse in a natural and intuitive interface. Installing m2eclipse is straightforward, simply point your Eclipse IDE installation to the Eclipse Update Sites. For instructions, prerequisites, and a demonstration video, go to Installing m2eclipse. Once you've installed m2eclipse, you can watch our m2eclipse videos to learn how to install m2eclipse and create your first Maven project with m2eclipse. For a more complete introduction to m2eclipse, Developing with Eclipse and Maven. Developing with Eclipse and Maven is a free, online book, which provides comprehensive documentation for the m2eclipse Maven integration for Eclipse."

"An "executable" UML model is one with a behavioral specification detailed enough that it can effectively be "run" as a program. This can be extremely valuable in order to test and validate the model, independently of the one or more implementation platforms to which the system being modeled will ultimately be deployed. Or, in some cases, the model itself can actually be run as the production implementation, given an appropriate execution environment. There have been model execution tools and environments for years, even before UML. However, each tool defined its own semantics for model execution, often including a proprietary action language, and models developed in one tool could not be interchanged with or interoperate with models developed in another tool. A previous post described Stephen Mellor's quest of more than a decade to change this through OMG standards for precise UML model execution semantics and a UML action language. In 2008, this led to the adoption of the Foundational UML (fUML) specification, providing the first precise operational and base semantics for a subset of UML encompassing most object-oriented and activity modeling. The fUML specification still did not provide any new concrete surface syntax, however, tying the precise semantics solely to the existing abstract syntax model of UML. This meant that, in order to fully specify a detailed behavior in a UML model - say the effect behavior of a transition on a state machine or the method of an operation of a class - one still had to draw a very detailed, graphical activity diagram. "

Caching is the most important performance optimization technique. There are many things that can be cached in persistence, objects, data, database connections, database statements, query results, meta-data, relationships, to name a few. Caching in object persistence normally refers to the caching of objects or their data. Caching also influences object identity, that is that if you read an object, then read the same object again you should get the identical object back (same reference). JPA 1.0 does not define a shared object cache, JPA providers can support a shared object cache or not, however most do. Caching in JPA is required with-in a transaction or within an extended persistence context to preserve object identity, but JPA does not require that caching be supported across transactions or persistence contexts. JPA 2.0 defines the concept of a shared cache. The @Cacheable annotation or cacheable XML attribute can be used to enable or disable caching on a class.

"Apache Tuscany simplifies the task of developing SOA solutions by providing a comprehensive infrastructure for SOA development and management that is based on Service Component Architecture (SCA) standard. With SCA as it's foundation, Tuscany offers solution developers the following advantages: Provides a model for creating composite applications by defining the services in the fabric and their relationships with one another. The services can be implemented in any technology. Enables service developers to create reusable services that only contain business logic. Protocols are pushed out of business logic and are handled through pluggable bindings. This lowers development cost. Applications can easily adapt to infrastructure changes without recoding since protocols are handled via pluggable bindings and quality of services (transaction, security) are handled declaratively. Existing applications can work with new SCA compositions. This allows for incremental growth towards a more flexible architecture, outsourcing or providing services to others. In addition, Tuscany is integrated with various technologies and offers: a wide range of bindings (pluggable protocols) various component types including and not limited to Java, C++, BPEL, Spring and scripting an end to end service and data solution which includes support for Jaxb and SDO a lightweight runtime that works standalone or with other application servers a modular architecture that makes it easy to integrate with different technologies and to extend Integration with web20 technologies Apache Tuscany SCA is implemented in Java and C++ (referred to as Native)"

"Quercus is Caucho Technology's 100% Java implementation of PHP 5 released under the Open Source GPL license. Quercus comes with many PHP modules and extensions like PDF, PDO, MySQL, and JSON. Quercus allows for tight integration of Java services with PHP scripts, so using PHP with JMS or Grails is a quick and painless endeavor. With Quercus, PHP applications automatically take advantage of Java application server features just as connection pooling and clustered sessions. Quercus implements PHP 5 and a growing list of PHP extensions including APC, iconv, GD, gettext, JSON, MySQL, Oracle, PDF, and Postgres. Many popular PHP application will run as well as, if not better, than the standard PHP interpreter straight out of the box. The growing list of PHP software certified running on Quercus includes DokuWiki, Drupal, Gallery2, Joomla, Mambo, Mantis, MediaWiki, Phorum, phpBB, phpMyAdmin, PHP-Nuke, Wordpress and XOOPS. Quercus presents a new mixed Java/PHP approach to web applications and services where Java and PHP tightly integrate with each other. PHP applications can choose to use Java libraries and technologies like JMS, EJB, SOA frameworks, Hibernate, and Spring. This revolutionary capability is made possible because 1) PHP code is interpreted/compiled into Java and 2) Quercus and its libraries are written entirely in Java. This architecture allows PHP applications and Java libraries to talk directly with one another at the program level. To facilitate this new Java/PHP architecture, Quercus provides and API and interface to expose Java libraries to PHP. The Quercus .war file can be run on Java application servers such as Glassfish, i.e. it can be run outside of Resin. This .war file includes the Quercus interpreter and the PHP libraries."

"Let's imagine we want to create an application for orders. People can sign in to the system, place orders for various items, check out and have them sent to their address. Very simple, but we can show a lot of things here. As we expect to be writing more than one application of this type and as we also would like to be able to express the structure of the application on a business level (one of the major drivers for DSLs and MDSD for that matter), we come up with the idea of using a DSL to describe what the application does. Defining the DSL is what we did last week. This week, we need to map the concepts of the DSL to some code and some APIs we're going to program against. So, we're going to create a set of code templates for a code generator that can then read our DSL models and create persistence code for us."

" OT/J: extreme modularity Whenever modularity gets tricky, OT/J provides just one more dimension for your architecture. With OT/J there's no excuse for any architectural workarounds. OT/J: extreme reuse With OT/J any existing piece of Java code is reusable. Existing components can be adapted to specific needs in full adherence to your projects requirements and without compromising a crisp modular architecture. The fabric for quality software OT/J is the fabric from which high quality software can be produced: flexible, durable, elegant. OT/J in the Wiki"

"The past year I've been learning a lot of Scala and I'm currently working on a new project using Scala. I use LiquiBase, which is a database-independent library for tracking, managing and applying database changes. I'm also using the simple-build-tool (SBT) for my project. So I've put together a little SBT plug-in for running LiquiBase maintenance commands (update, rollback, …) from within SBT. For example, whenever I want to apply new database changes with LiquiBase I can now simply run sbt liquibase-update which sets up a new instance of LiquiBase and executes the LiquiBase update command which migrates my database to the latest version. At the moment the plug-in supports the following commands: liquibase-update, liquibase-drop, liquibase-tag, liquibase-rollback and liquibase-validate. What are the benefits of using the plug-in and not just the LiquiBase CLI? * no download/install of LiquiBase * classpath handled by SBT * no need to provide a big list of parameters or writing shell scripts The plug-in is called liquibase-sbt-plugin and you can find it here on GitHub. Feel free to use it or fork it and suggest changes. I'm still relatively new to Scala and especially SBT so any remarks are very welcome."

I am working on a web site that will help students practice their Scala programming skills. As I labored along, writing my JSF app code, I thought "this is silly-why not practice Scala at the same time?" But I like JSF and wasn't ready to jump to Lift or Vaadin. With Eclipse, this isn't all that hard. Install the Java plugin. Make a dynamic web project in the usual way, using the Java EE perspective. Then, switch to the Scala perspective, right-click on the project, and, if all planets are aligned correctly, you will get a menu item "Add Scala nature". (If they are not, see here for a manual approach.) Add your managed beans as Scala classes. Finally, switch back to the Java EE perspective, select the project properties, and add the Scala library JAR as a Java EE module dependency. But I like NetBeans and wasn't ready to switch to Eclipse. (Unfortunately, JSF 2 support in Eclipse is pretty minimal, the Glassfish integration is a bit flaky, and the Scala plugin has very little usable code completion.) NetBeans doesn't let me add a "Scala nature" to a web project. If I add Scala files to the project, I can edit them with the Scala editor, but they just get copied to the WAR file, without any compilation. I had one look at the Ant scripts for a Scala and a web project and decided that I wasn't going to figure out how to merge them. This blog shows how you can use Maven to make a mixed Scala/Java project in NetBeans. So I gathered up JSF and Scala pom.xml files from here and here, cut out the considerable crud from the JSF POM file that was probably meant for supporting Tomcat, and merged the results to the best of my ability-see below. You use the usual Maven directory structure, but with a src/main/scala directory instead of src/main/java:

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:

"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. "