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Davor Poldrugo

The ASF Resigns From the JCP Executive Committee - 0 views

  • Oracle provided the EC with a Java SE 7 specification request and license that are self-contradictory, severely restrict distribution of independent implementations of the spec, and most importantly, prohibit the distribution of independent open source implementations of the spec.  Oracle has refused to answer any reasonable and responsible questions from the EC regarding these problems.
  • In the phrase "fail to uphold their responsibilities under the JSPA", we are referring to Oracle's refusal to provide the ASF's Harmony project with a TCK license for Java SE that complies with Oracle's obligations under the JSPA as well as public promises made to the Java community by officers of Sun Microsystems (recently acquired by Oracle.)
  • it should be noted that the majority of the EC members, including Oracle, have publicly stated that restrictions on distribution such as those found in the Java SE 7 license have no place in the JCP - and two distinguished individual members of the EC, Doug Lea and Tim Peierls, both have resigned in protest over the same issue.
  • ...9 more annotations...
  • By approving Java SE 7, the EC has failed on both counts : the members of the EC refused to stand up for the rights of implementers, and by accepting Oracle's TCK license terms for Java SE 7, they let the integrity of the JCP's licensing structure be broken.
  • The Apache Software Foundation concludes that that JCP is not an open specification process
  • and finally, the EC is unwilling or unable to assert the basic power of their role in the JCP governance process
  • In short, the EC and the Java Community Process are neither.
  • To that end, our representative has informed the JCP's Program Management Office of our resignation, effective immediately.  As such, the ASF is removing all official representatives from any and all JSRs. In addition, we will refuse any renewal of our JCP membership and, of course, our EC position.
  • Okay ! Java's privatized now... What now ?
  • Thank god I moved off Java in time. Suddenly Oracle is the new Death Star, replacing Microsoft.
  • This is a sad, sad day in the Java community. I hoped that Oracle would back-peddle and realize the folly of their ways. Now Java will be to Oracle what .NET is to Microsoft and it will be the death of Java as we know it.
  • Posibly in few years we'll see Apache as a new Sun for "Java", followed by Eclipse, Google, etc... I hope this is a great movement done by Apache for the community. We'll see... The objetive of Oracle are Enterprises that cannot move from Java because of hight investments, it will earn a lot of money from them. Oracle ignores the community because is not going to pay for (expensive, as all the rest of Oracle products) licenses... We'll se...
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    The Apache Software Foundation has resigned its seat on the Java SE/EE Executive Committee. Apache has served on the EC for the past 10 years, winning the JCP "Member of the Year" award 4 times, and recently was ratified for another term with support from 95% of the voting community. Further, the project communities of the ASF, home to Apache Tomcat, Ant, Xerces, Geronimo, Velocity and nearly a 100 mainstay java components have implemented countless JSRs and serve on and contribute to many of the JCPs technical expert groups. We'd like to provide some explanation to the community as to why we're taking this significant step.
Hendy Irawan

Equinox Aspects - 0 views

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    Aspect-oriented computing is continuing to increase in popularity. The modularity inherent in OSGi and Eclipse offers unique opportunities for managing and applying aspects by supplying them in bundles and directing their application to particular sets of bundles. This incubator work area is dedicated to delivering an integration of aspects and OSGi. The goal is to allow developers to use the Equinox together with AspectJ by combining the benefits of both worlds. Using a load-time weaving extension you are able to add AspectJ aspects to your bundle-based system just by putting them into general OSGi bundles. It does not matter if the pointcuts you defined inside the aspects contain join points that are defined by classes within the same bundle or any other bundle in your installation. The load-time weaving extension will take care that your aspects are woven with the appropriate classes at load-time. To illustrate this lets assume the following situation: You would like to write an aspect that traces something within the JDT plug-ins of Eclipse. Without some kind of load-time aspect weaving you would somehow need to recompile those JDT plug-ins using AJDT (for example) together with your aspect. By using the load-time aspect weaving extension all you need is to implement your aspect and add that bundle to your system. The load-time aspect weaving extension takes care of weaving your aspect with the JDT code as it is loaded. And it doesn't matter if a new JDT is installed by the user later on. The next time your application is started the load-time aspect weaving will take care of weaving your aspect into these bundles as well, if necessary. With this technology is becomes possible to modularize crosscutting concerns across different plug-ins while keeping the idea of separate compilation for bundles. Goals Provide Runtime Modularity and Versioning for Crosscutting Concerns: Aspects are used to implement crosscutting concerns. However such concerns usually compr
Hendy Irawan

Apache Commons Daemon : Java based daemons or services - 0 views

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    "Since 1994, the Java programming language evolved and became a valid tool to develop reliable and performant server applications as opposed to just applets and client applications. The major disadvantage of the Java platform is that still today the only portable way to start a Java application relies on a single point of entry: the public static void main(String[]) method. Having a single-point of entry is a valid solution for client applications, where interactively a user can command to the application to quit (which can terminate the Virtual Machine process at calling the System.exit(int) method), but in those cases where the application is not interactive (server applications) there is currently no portable way to notify the Virtual Machine of its imminent shutdown. A server application written in Java might have to perform several tasks before being able to shutdown the Virtual Machine process. For example in the case of a Servlet container, before the VM process is shut down, sessions might need to be serialized to disk, and web applications need to be destroyed. One common solution to this problem is to create (for example) a ServerSocket and wait for a particular message to be issued. When the message is received, all operations required to shut down the server applications are performed and at the end the System.exit method is called to terminate the Virtual Machine process. This method however, has several disadvantages and risks: In case of a system-wide shutdown, the Virtual Machine process may be shut down directly by the operating system without notifying the running server application. If an attacker finds out the shutdown message to send to the server and discovers a way to send this message, he can easily interrupt the server's operation, bypassing all the security restrictions implemented in the operating system. Most multi-user operating systems already have a way in which server applications are started and stopped. Under Unix based
Hendy Irawan

JScience - 0 views

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    "Implementation of Units of Measurement services. A coordinates module compliant with OGC/ISO specifications for the development and deployment of geographic applications. A rigourous mapping of mathematical structures (e.g. Group, Ring, Field, VectorSpace ) to Java interfaces. A linear algebra module, which includes a first (and I believe unique) parameterized matrix class capable of resolving linear system of equations involving any kind of elements (e.g. Complex, ModuloInteger, RationalFunctions) A functions module for symbolic calculations and analysis. Different types of numbers such as real numbers of arbitrary and guaranteed precision, or the always exact rational numbers. Support for exact or arbitrary precision measurements (also strongly typed). Support for Standard , Relativistic , High-Energy , Quantum and Natural physical models. A monetary module for precision-guaranteed calculations and currencies conversions."
Hendy Irawan

Scout/Overview - Eclipsepedia - 0 views

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    The goal of the Eclipse Scout project is making it easy to build distributed enterprise applications based on the Eclipse platform. It consists of a runtime framework providing transparent service communication between the client and backend part and is shipped with a rich set of common user interface components. The user interface is not built for a particular rendering technology but it encapsulates the core functionality into a headless model. GUI factories are available for rendering the client model into a particular target UI platform. SWT and Swing are supported out of the box and an AJAX GUI factory could be easily added. Developing Scout applications is supported by the Scout SDK, a plug-in set built on top of Eclipse PDE and Eclipse JDT. The Scout SDK works directly on the bare Java resources and assists the development task by providing an augmented view on the underlying Java code. Additionally, it comes with a rich set of wizards and operations for modifying the Scout application project just by editing the underlying Java code. There is no meta-data required. Hence a developer can switch between editing resources using Eclipse's standard editors and leveraging the features of Scout SDK at any point in time. Eclipse Scout can be used to create multi-tier client/server applications, standalone client applications or OSGi-based server applications. Basically, there are three main advantages when choosing Scout as your framework for building such applications. First, the Scout runtime is service oriented by design. Almost every functionality is provided as an OSGi service. Every OSGi bundle may make use of them. Second, Scout provides a rich set of UI elements being uncoupled from a particular GUI technology. And third, building distributed client/server applications is as easy as if both parts would run within the same local JVM.
Hendy Irawan

AtomServer 2.3.4 - - 0 views

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    "AtomServer is a generic data store implemented as a RESTful web service. It is designed as a GData-style Atom Store. It is based on the following concepts and protocols; REST. REST is a design pattern. It's not a technology like SOAP or HTTP. REST is a proven design pattern for building loosely-coupled, highly-scalable applications. There are important benefits to sticking to the REST design pattern; Simple. REST is incredibly simple to define. There are just a handful of principles and well defined semantics associated with it. Scalable. REST leads to a very scalable solution by promoting a stateless protocol and allowing state to be distributed across the web. Layered. REST allows any number of intermediaries, such as proxies, gateways, and firewalls. Ultimately REST is just a web site, albeit one that adheres to a design pattern, so one can easily layer aspects such as Security, Compression, etc. on an as needed basis. Atom. Fundamentally, Atom is an XML vocabulary for describing lists of timestamped entries. These entries can be anything, although because Atom was originally conceived to replace RSS, Atom lists are Feeds, and the items in the lists are Entries. Atom is a RESTful protocol. AtomServer stands on the shoulders of giants. It is built on top of several open source projects - most notably, Apache Abdera (a Java-based Atom Publishing framework) and Spring. AtomServer is an Atom Store. Thus, it requires a relational database to run. AtomServer currently supports; PostgresSQL, SQLServer, and HSQLDB. Using HSQLDB, AtomServer requires zero configuration and can run out-of-the-box. While this configuration is suitable for many applications, those that see significant load will likely require a database with better transactional semantics, such as PostgreSQL. AtomServer is easy to use. It deploys as a simple WAR file into any Servlet container. Or alternately, can be used out-of-the-box as a standalone server, running with
Hendy Irawan

Ajax Push - Overview - ICEfaces - ICEfaces.org Community Wiki - 0 views

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    Ajax Push allows the application to incrementally update any part of the page at any time, for any group of clients. This is a small change in terms of the technical capabilities of Ajax applications, but it is a revolutionary change in terms of what applications can actually provide to users. Ajax Push is the key to building collaborative multi-user applications for the web. Under the Hood The intricacies of the Ajax Push implementation are completely transparent to the ICEfaces developer, as you work with a straightforward set of APIs. It is, however, useful to understand the basic mechanics. Ajax Push in ICEfaces 2.0 leverages an asynchronous notification mechanism call ICEpush. Simply put, ICEpush uses long polling to provide asynchronous notification over standard HTTP, using only standard browser capabilities. The sequence of events involved in Ajax Push is illustrated below.
Hendy Irawan

Apache CXF -- Index - 0 views

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    Apache CXF is an open source services framework. CXF helps you build and develop services using frontend programming APIs, like JAX-WS and JAX-RS. These services can speak a variety of protocols such as SOAP, XML/HTTP, RESTful HTTP, or CORBA and work over a variety of transports such as HTTP, JMS or JBI. CXF includes a broad feature set, but it is primarily focused on the following areas: Web Services Standards Support: CXF supports a variety of web service standards including SOAP, the WS-I Basic Profile, WSDL, WS-Addressing, WS-Policy, WS-ReliableMessaging, WS-Security, WS-SecurityPolicy, WS-SecureConverstation, and WS-Trust (partial). Frontends: CXF supports a variety of "frontend" programming models. CXF implements the JAX-WS APIs (TCK compliant). CXF JAX-WS support includes some extensions to the standard that make it significantly easier to use, compared to the reference implementation: It will automatically generate code for request and response bean classes, and does not require a WSDL for simple cases. It also includes a "simple frontend" which allows creation of clients and endpoints without annotations. CXF supports both contract first development with WSDL and code first development starting from Java. For REST, CXF also supports a JAX-RS (TCK compliant) frontend. Ease of use: CXF is designed to be intuitive and easy to use. There are simple APIs to quickly build code-first services, Maven plug-ins to make tooling integration easy, JAX-WS API support, Spring 2.x XML support to make configuration a snap, and much more. Binary and Legacy Protocol Support: CXF has been designed to provide a pluggable architecture that supports not only XML but also non-XML type bindings, such as JSON and CORBA, in combination with any type of transport. To get started using CXF, check out the downloads, the user's guide, or the mailing lists to get more information!
Rinav G

Overview (Java Platform SE 6) - 0 views

  • Package java.util.concurrent.atomic A small toolkit of classes that support lock-free thread-safe programming on single variables.
  • A small toolkit of classes that support lock-free thread-safe programming on single variables. In essence, the classes in this package extend the notion of volatile values, fields, and array elements to those that also provide an atomic conditional update operation of the form: boolean compareAndSet(expectedValue, updateValue);
  • Atomic classes are not general purpose replacements for java.lang.Integer and related classes. They do not define methods such as hashCode and compareTo. (Because atomic variables are expected to be mutated, they are poor choices for hash table keys.)
  • ...4 more annotations...
  • The specifications of these methods enable implementations to employ efficient machine-level atomic instructions that are available on contemporary processors.
  • java.util.concurrent.atomic Class AtomicInteger java.lang.Object java.lang.Number java.util.concurrent.atomic.AtomicInteger
  • An int value that may be updated atomically. See the java.util.concurrent.atomic package specification for description of the properties of atomic variables. An AtomicInteger is used in applications such as atomically incremented counters, and cannot be used as a replacement for an Integer. However, this class does extend Number to allow uniform access by tools and utilities that deal with numerically-based classes.
  • int incrementAndGet()           Atomically increments by one the current value.
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    Package java.util.concurrent.atomic Description A small toolkit of classes that support lock-free thread-safe programming on single variables. In essence, the classes in this package extend the notion of volatile values, fields, and array elements to those that also provide an atomic conditional update operation of the form: boolean compareAndSet(expectedValue, updateValue);
Rinav G

Design Patterns: Front Controller - 0 views

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    Many interactive Web applications are composed of brittle collections of interdependent Web pages. Such applications can be hard to maintain and extend. The Front Controller pattern defines a single component that is responsible for processing application requests. A front controller centralizes functions such as view selection, security, and templating, and applies them consistently across all pages or views. Consequently, when the behavior of these functions need to change, only a small part of the application needs to be changed: the controller and its helper classes.
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    Many interactive Web applications are composed of brittle collections of interdependent Web pages. Such applications can be hard to maintain and extend. The Front Controller pattern defines a single component that is responsible for processing application requests. A front controller centralizes functions such as view selection, security, and templating, and applies them consistently across all pages or views. Consequently, when the behavior of these functions need to change, only a small part of the application needs to be changed: the controller and its helper classes.
Rinav G

[JavaSpecialists 177] - Logging Part 3 of 3 - 0 views

  • Writing your own logging framework is the perfect coding crime.
  • Writing your own logging framework is the perfect coding crime
  • Even the Sun engineers fell into this trap. Prior to Java 4, we had a perfectly good logging framework in Log4J. However, instead of adopting this into the standard Java distribution, we ended up with java.util.logging. There are lots of Java logging frameworks available, even meta-logging frameworks like SLF4J and Jakarta Commons. These are supposed to abstract the logging frameworks so you can change the implementation without touching your code.
  • ...5 more annotations...
  • Logging Levels
  • In Log4J for example, we have six default levels, FATAL, ERROR, WARNING, INFO, DEBUG and TRACE.
  • Since it is tricky assigning the correct levels in our code, we should regularly do code reviews with specific emphasis on logging levels.
  • We should be able to adjust the log levels of our individual components at runtime without restarting our application.
  • Silent Operation
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    Writing your own logging framework is the perfect coding crime. If you can convince your manager to put it on the project plan, you are guaranteed to have success. At the end of each day, you will go home feeling happy and satisfied. It will feel like you are doing something creative. You will get the intellectual stimulation without the risk of failure. Even the Sun engineers fell into this trap. Prior to Java 4, we had a perfectly good logging framework in Log4J. However, instead of adopting this into the standard Java distribution, we ended up with java.util.logging. There are lots of Java logging frameworks available, even meta-logging frameworks like SLF4J and Jakarta Commons. These are supposed to abstract the logging frameworks so you can change the implementation without touching your code. http://www.javaspecialists.eu/archive/Issue177.html
Hendy Irawan

Welcome to Migrate4j - 0 views

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    migrate4j is a database migration tool. Suppose you determine that you need a new database table for your project. If you develop alone, you could write an SQL script that adds a table and manually apply this to your development system. But if you work with other developers, or need to keep a test system in synch with your development system, this become tedious and error prone. Migration tools make it possible to add your new table (or make any other schema changes) in an automated fashion, ensuring all your systems are always in synch. Migration tools also make it possible to quickly and easily roll back previous changes. Unlike typing commands into an interactive SQL window or storing SQL scripts, migration tools keep a detailed history of how your database schema evolved (just in case you need to go back to a previous version). Finally, migration tools minimize or eliminate the problem of having to use vendor specific syntax - you may never switch database products, but if you do, using a migration tool will make your life much easier. The initial intent of migrate4j was to make a Java version of Ruby's db:migrate. If you've used db:migrate, you probably fell in love with it's simple syntax, easy configuration and ability to roll changes up and back effortlessly. The intent (and the challenge) of migrate4j is to bring the power and simplicity of db:migrate to Java programmers, using familiar type safety and syntax. Along the way, we're adding additional functionality that makes migrate4j more than just another Ruby tool rewritten for Java - it is a Java project intended to make other Java projects even better.
Hendy Irawan

Sapphire - 0 views

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    Sapphire - develop UI without wiring individual widgets Little has changed in the way Java desktop UI is written since the original Java release. Technologies have changed (AWT, Swing, SWT, etc.), but fundamentals remain the same. The developer must choose which widgets to use, how to lay those widgets out, how to store the data being edited and how to synchronize the model with the UI. Even the best developers fall into traps of having UI components talk directly to other UI components rather than through the model. Inordinate amount of time is spent debugging layout and data-binding issues. Sapphire aims to raise UI writing to a higher level of abstraction. The core premise is that the basic building block of UI should not be a widget (text box, label, button, etc.), but rather a property editor. Unlike a widget, a property editor analyzes metadata associated with a given property, renders the appropriate widgets to edit that property and wires up data binding. Data is synchronized, validation is passed from the model to the UI, content assistance is made available, etc. This fundamentally changes the way developers interact with a UI framework. Instead of writing UI by telling the system how to do something, the developer tells the system what they intend to accomplish. When using Sapphire, the developer says "I want to edit LastName property of the person object". When using widget toolkits like SWT, the developer says "create label, create text box, lay them out like so, configure their settings, setup data binding and so on". By the time the developer is done, it is hard to see the original goal in the code that's produced. This results in UI that is inconsistent, brittle and difficult to maintain.
anonymous

Large scale application development and MVP - Part II - Google Web Toolkit - Google Code - 0 views

  • itself
    • anonymous
       
      The View Implementation
  • @UiHandler("
  • presenter.onAddButtonClicked();
  • ...91 more annotations...
  • onAddButtonClicked
  • eventBus.fireEvent(new AddContactEvent());
  • presenter needs to know more about the view
  • view needs to know more about the data model
  • data types are typically homogeneous within column borders
  • ColumnDefinition abstract class
  • houses the any type-specific code (this is the third party mentioned above)
  • ColumnDefinition
  • ColumnDefinition(s) would be created outside of the presenter
  • we can reuse its logic regardless of what view we've attached ourself to
  • update our views such that we can set their ColumnDefinition(s).
  • setColumnDefinitions
  • this.columnDefinitions = columnDefinitions;
  • so that we can pass in
  • a mocked ContactsView instance when testing our ContactsPresenter
  • in our AppController, when we create the ContactsView,
  • new ContactsViewColumnDefinitions().getColumnDefinitions();
  • we can initialize it with the necessary ColumnDefinition(s).
  • contactsView.setColumnDefiniions(
    • anonymous
       
      Initialize ContactsView with the necessary ColumnDefinition(s)
  • With our ColumnDefinition(s) we can pass the model untouched.
  • As mentioned above we were previously dumbing down the model into a list of Strings
  • current solution
  • List<String> data
  • display.setData(data);
  • how that data type is rendered.
  • use generics
  • third party that abstracts
  • knowledge of a cell's data type
  • stringing together a list of these classes
  • providing the necessary render()
  • and isClickable()/isSelectable() override
  • ContactsViewColumnDefinitions<ContactDetails>
  • columnDefinitions =      new ArrayList<ColumnDefinition<ContactDetails>>()
  • ColumnDefinition<T>
  • ContactsPresenter
  • ContactsViewImpl
  • ColumnDefinition<T> columnDefinition = columnDefinitions.get(j);
  • the presenter can pass the model untouched
  • the view has no rendering code
  • that we would otherwise need to test. And the fun doesn't stop there.
  • presenter.onItemClicked(
  • presenter.onItemSelected
  • ClickEvent
  • cell.getCellIndex()
  • columnDefinition.isClickable()
  • SelectEvent
  • columnDefinition.isSelectable()
  • return shouldFireClickEvent;
  • return shouldFireSelectEvent;
  • respond to user interaction in different ways based upon the cell type that was clicked
  • use them for rendering purposes
  • defining how to interpret user interactions
  • we're going to remove any application state from the ContactsView
  • replace the view's getSelectedRows() with a SelectionModel
  • The SelectionModel is nothing more than a wrapper around a list of model objects.
  • ContactsPresenter holds on to an instance of this class
  • onItemSelected
  • Having the ColumnDefinition create a new widget for each cell is too heavy
  • Replace our FlexTable implementation with an HTML widget
  • calling setHTML()
  • Reduce the event overhead by sinking events on the HTML widget
  • rather than the individual cells
  • update our ContactsView.ui.xml file to use a
  • HTML widget rather than a FlexTable widget.
  • <g:HTML ui:field="contactsTable">
  • Inefficiencies related to inserting new elements via DOM manipulation Overhead associated with sinking events per Widget
  • for each item ask our column definitions to render accordingly
  • each column definition
  • render itself into the StringBuilder
  • rather than passing back a full-on widget
  • calling setHTML on a HTML widget
  • rather than calling setWidget on a FlexTable.
  • This will decrease your load time, especially as your tables start to grow.
  • we're reducing the overhead of sinking events on per-cell widgets
  • instead sinking on a single container
  • ClickEvents are still wired up via our UiHandler annotations
  • get the Element that was clicked on
  • and walk the DOM until we find a parent TableCellElement
  • we can determine the row
  • shouldFirdClickEvent() and shouldFireSelectEvent()
  • to take as a parameter a TableCellElement rather than a HTMLTable.Cell.
  • faster startup times via Code Splitting.
  • runAsync() points
  • split portion of your code is purely segmented
  • not referenced by other parts of the app
  • it will be downloaded and executed at the point that it needs to run
  • Do we really want to download all of that code before the user even logs in?
  • Not really.
  • simply grab the login code, and leave the rest for when we actually need it
  • wrap the code that creates the ContactsView and ContactsPresenter in a runAsync() call
  • as optimizations such as this one become easier and easier to implement.
Hendy Irawan

6. Validation, Data Binding, and Type Conversion - Spring Framework - 0 views

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    "There are pros and cons for considering validation as business logic, and Spring offers a design for validation (and data binding) that does not exclude either one of them. Specifically validation should not be tied to the web tier, should be easy to localize and it should be possible to plug in any validator available. Considering the above, Spring has come up with a Validator interface that is both basic ands eminently usable in every layer of an application. Data binding is useful for allowing user input to be dynamically bound to the domain model of an application (or whatever objects you use to process user input). Spring provides the so-called DataBinder to do exactly that. The Validator and the DataBinder make up the validation package, which is primarily used in but not limited to the MVC framework. The BeanWrapper is a fundamental concept in the Spring Framework and is used in a lot of places. However, you probably will not have the need to use the BeanWrapper directly. Because this is reference documentation however, we felt that some explanation might be in order. We will explain the BeanWrapper in this chapter since, if you were going to use it at all, you would most likely do so when trying to bind data to objects. Spring's DataBinder and the lower-level BeanWrapper both use PropertyEditors to parse and format property values. The PropertyEditor concept is part of the JavaBeans specification, and is also explained in this chapter. Spring 3 introduces a "core.convert" package that provides a general type conversion facility, as well as a higher-level "format" package for formatting UI field values. These new packages may be used as simpler alternatives to PropertyEditors, and will also be discussed in this chapter."
Hendy Irawan

Apache Tomcat - Welcome! - 0 views

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    "Apache Tomcat is an open source software implementation of the Java Servlet and JavaServer Pages technologies. The Java Servlet and JavaServer Pages specifications are developed under the Java Community Process. Apache Tomcat is developed in an open and participatory environment and released under the Apache License version 2. Apache Tomcat is intended to be a collaboration of the best-of-breed developers from around the world. We invite you to participate in this open development project. To learn more about getting involved, click here. Apache Tomcat powers numerous large-scale, mission-critical web applications across a diverse range of industries and organizations. Some of these users and their stories are listed on the PoweredBy wiki page."
Hendy Irawan

Java EE 6 and Scala » Source Allies Blog - 0 views

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    Last weekend while pondering the question "Is Scala ready for the enterprise?" I decided to write a simple Java EE 6 app entirely in Scala, without using any Java. I had three main reasons for doing this: one was just to see how easy/difficult it would be to write everything in Scala (it was easy).  Another was to document the process for others journeying down the same road (the entire project is on github).  Finally, I wanted to identify advantages of using Scala instead of Java that are specific to Java EE apps (I found several). Background The specific app I created was an adaptation of the Books example from Chapter 10 of Beginning Java™ EE 6 Platform with GlassFish™ 3. It's a simple web app that displays a list of books in a database and lets you add new books. Although it's a pretty trivial app, it does touch on several important Java EE 6 technologies: JPA 2.0, EJB 3.1 and JSF 2.0.
anonymous

Getting Started with RequestFactory - Google Web Toolkit - Google Code - 0 views

  • Entity Proxies
    • anonymous
       
      Proxy type (on the Client) vs Entity type (on the server)
  • proxy types
  • entity types
  • ...147 more annotations...
  • methods that return service stubs
  • one RequestFactory interface for your application
  • employeeRequest();
  • @Service(Employee.class)
  • extends RequestContext
  • extends RequestFactory
  • service stub
  • RequestFactory service stubs
  • must extend RequestContext
  • The methods in a service stub do not return entities directly
  • return subclasses of com.google.gwt.requestfactory.shared.Request.
  • This allows the methods on the interface to be invoked asynchronously with
  • Request.fire()
  • fire(    new Receiver()
  • onSuccess
  • callers pass an AsyncCallback that implements onSuccess()
  • takes a Receiver which must implement onSuccess()
  • Receiver is an abstract class having a default implementation of onFailure()
  • you can extend Receiver and override onFailure()
  • onViolation()
  • any constraint violations on the server
  • The Request type returned from each method
  • parameterized with the return type of the service method.
  • Methods that have no return value should return type Request<Void>
  • BigDecimal, BigInteger, Boolean, Byte, Enum, Character, Date, Double, Float, Integer, Long, Short, String, Void
  • subclass of EntityProxy
  • List<T> or Set<T>
  • primitive types are not supported
  • methods that operate on an entity itself
  • like persist() and remove()
  • return objects of type InstanceRequest rather than Reques
  • Server Implementations
  • methods defined in an
  • entity's service interface
  • implemented in the class named
  • @Service annotation
  • in these examples, is the entity class
  • service implementations do not directly implement the RequestContext interface
  • server-side implementations use the domain entity types
  • @Entity
  • EntityManager
  • createQuery
  • getResultList();
  • entityManager()
  • createEntityManager()
  • em.persist(this);
  • em.remove(attached
  • em.close();
  • defined in the service's
  • RequestContext interface
  • even though the implementation does not formally implement the interface in Java
  • name and argument list for each method
  • same on client and server
  • Client side methods
  • return Request<T>
  • only T on the server
  • EntityProxy types become the domain entity type on the server
  • Methods that return a Request object in the client interface are implemented as static methods on the entity
  • Methods that operate on a single instance of an entity, like persist() and remove(),
  • eturn an
  • InstanceRequest
  • in the client interface
  • Instance methods do not pass the instance directly, but rather via the
  • using()
  • instance methods must be implemented as non-static methods in the entity type
  • Four special methods are required on all entities
  • as they are used by the RequestFactory servlet:
  • constructor
  • findEntity
  • An entity's getId()
  • is typically auto-generated by the persistence engine (JDO, JPA, Objectify, etc.)
  • "find by ID" method has a special naming convention
  • find()
  • "find" plus the type's simple name
  • On the server
  • getVersion() method is used by RequestFactory to infer if an entity has changed
  • backing store (JDO, JPA, etc.) is responsible for updating the version each time the object is persisted,
  • RequestFactoryServlet sends an UPDATE
  • if an entity changes as
  • Second, the client maintains a version cache of recently seen entities
  • Whenever it sees an entity whose version has changed, it fires
  • UPDATE events on the event bus
  • so that listeners can update the view
  • GWT.create
  • and initialize it with your application's EventBus
  • GWT.create
  • requestFactory.initialize
  • create a new entity on the client
  • EmployeeRequest request
  • EmployeeProxy newEmployee
  • All client-side code should use the EmployeeProxy
  • not the Employee entity itself
  • unlike GWT-RPC, where the same concrete type is used on both client and server
  • RequestFactory
  • designed to be used with an ORM layer like JDO or JPA
  • on the server
  • to build data-oriented (CRUD) apps with an ORM-like interface
  • on the client
  • easy to implement a data access layer
  • structure your server-side code in a data-centric way
  • GWT-RPC, which is service-oriented
  • On the client side, RequestFactory keeps track of objects that have been modified and sends only changes
  • lightweight network payloads
  • solid foundation for automatic batching and caching of requests in the future
  • RequestFactoryServlet
  • RequestFactory uses its own servlet
  • own protocol
  • not designed for general purpose services like GWT-RPC
  • implements its
  • It is designed specifically for implementing a persistence layer on both client and server.
  • In persistence frameworks like JDO and JPA, entities are annotated with
  • client-side representation of an entity
  • known as a
  • DTO (Data Transfer Object)
  • hook used to indicate that an object can be managed by RequestFactory
  • RequestFactory
  • EntityProxy interface
  • automatically populates bean-style properties between entities on the server and the corresponding EntityProxy on the client,
  • send only changes ("deltas") to the server
  • extends EntityProxy
  • interface
  • @ProxyFor
  • reference the server-side entity being represented
  • It is not necessary to represent every property and method from the server-side entity in the EntityProxy
  • EntityProxyId returned by this method is used throughout RequestFactory-related classes
  • while getId() is shown in this example, most client code will want to refer to
  • EntityProxy.stableId() i
  • to represent any type
  • is not required to expose an ID and version
  • often used to represent embedded object types within entities
  • @Embedded
  • Address
  • Address type
  • POJO with no persistence annotations
  • Address is represented as a ValueProxy
  • extends ValueProxy
  • interface
  • extends EntityProxy
  • interface
  • AddressProxy
  • AddressProxy
  • ValueProxy can be used to pass any type to and from the server
  • RequestFactory
  • interface between your client and server code
  • RequestContext interface
  • The server-side service
  • must implement each method
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Java Training - InterThread Communication - 0 views

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    Inter Thread Communication is one of the distinct facility in multi threading application development of java. In real world Inter Thread communication based applications of java works faster when compared to all the other applications in java. Inter-thread communication is all about making synchronized threads communicate with each other. It is a mechanism in which a thread is paused running in its critical section and another thread is allowed to enter in the same critical section to be executed. It is implemented by following methods of Object class wait() : Tells the calling thread to give up monitor and go to sleep until some other thread enters the same monitor and call notify. Causes current thread to release the lock and wait until either another thread invokes the notify() method or the notifyAll() method for this object, or a specified amount of time has elapsed. The current thread must own this object's monitor.
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