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The Java SCA sub-project aims to provide enterprise-grade service infrastructure based on SCA. Some of our principles include:

  • Tuscany SCA is not just a reference implementation. We encourage innovation based on the tenets of SCA. A lot of work we do provides feedback to the specifications.
  • We build runtimes that are distributed under the Apache Software License.
  • We believe developing highly scalable service-based systems should be easier than it currently is.
  • We believe in providing users with flexibility and choice. We do not dictate programming models but support many. Our runtimes are designed to be highly extensible so users may customize them to fit their needs.
  • We provide frequent releases of our software so users can experience the newest features and have access to the latest bug fixes.

For those looking at or developing the Tuscany Java SCA source code this page provides some description of the code structure and associated conventions that are used.

Getting the Source - Subversion Access

The Java SCA project Subversion repository is located at https://svn.apache.org/repos/asf/incubator/tuscany/java/sca.

The respository can also be viewed online at http://svn.apache.org/viewvc/incubator/tuscany/java/

Anyone can check code out of Subversion. You only need to specify a username and password in order to update the Subversion repository, and only Tuscany committers have the permissions to do so.

Checking out from Subversion

Use a command like:

svn checkout https://svn.apache.org/repos/asf/incubator/tuscany/java/sca

Committing Changes to Subversion
Any Tuscany committer should have a shell account on svn.apache.org. Before you can commit, you'll need to set a Subversion password for yourself. To do that, log in to svn.apache.org and run the command svnpasswd.

Once your password is set, you can use a command like this to commit:

svn commit

If Subversion can't figure out your username, you can tell it explicitly:

svn --username <name> commit

Subversion will prompt you for a password, and once you enter it once, it will remember it for you. Note this is the password you configured with svnpasswd, not your shell or other password.

Getting Setup for Development

Prerequisites
Java SCA requires the following:

Some Definitions

Module - we use the term module to refer to a leaf of the maven build tree. I.e a directory containing source code and resources that will be compiled to a releasable artifatct, a jar file.

...

Source and Build Structure

Looking at the source code for Java SCA you will see the following directory structure. 

java/
 pom/parent/pom.xml
 ...
 sca/
   pom.xml - The maven pom that builds all of the releasable Tuscany Java SCA modules

   contrib/ - A temporary direcoty that holds modules not currently being developed or targetted for a release
     ...

   doc/ - Tuscany Java SCA documentation that will be included with the release
     ...

   itest/ - Integration tests that test system performace using combinations of Tuscan Java features
     pom.xml
     ...

   modules/ - A flat direcory structure holding all of the separate modules that make up Tuscany Java SCA. 
     pom.xml
     ...

   samples/ - Tuscany Java SCA samples which show how to use the various features of the software
     build.xml <-- Samples build with Ant as well as Maven - TBD
     pom.xml
     ...

Naming Conventions

  • Use all lowercases and dashes in folder names (like in the jar names)
  • Maven artifact id = tuscany-<folder name>
  • Package names within modules should include the module name so that source code can be located in the source tree easily. So, for example, the module
java/sca/module/implementation-java

contains code in the package structure

org.apache.tuscany.implementation.java.*

Module Location

If people want to work on some new modules that won't be part of the
next release and are not included in the top-down build, that's fine, we can
just avoid listing these modules in java/sca/modules/pom.xml. So, they
can be there in the same source tree but they won't break the release
top-down build, and they won't have to be building at all times.

Maven Build Structure

  • sca/pom.xml's parent will be pom/parent/pom.xml
  • Other poms will use the pom from the parent folder as parent pom
  • Group ids:
    org.apache.tuscany.sca
    org.apache.tuscany.sca.samples,
    org.apache.tuscan.sca.itest
  • Version of our modules will be specified once in java/sca/pom.xml, child poms don't need specify a version as they get it from their parent
  • pom names begin Apache Tuscany SCA
  • Eclipse projects are generated for all built modules using mvn -Peclipse eclipse:eclipse

Building From The Source

First of all check out all of the java source code.

svn checkout https://svn.apache.org/repos/asf/incubator/tuscany/java

Building the SCA source code is simple

cd java/sca
mvn

It should work even if you start with an empty Maven local repository, and it should always work. Build breaks should be avoided or get fixed quickly.This assumes that maven is able to retrieve a SNAPSHOT version of SDO (and of course the rest of software that SCA depends on) as we haven't built anything other than SCA here.

Coding Standards

There are a few simple guidelines when developing for JAVA SCA:

  • Formatting standards are defined by the .checkstyle and .pmd configurations in the source repository. Please be sure to check code is formatted properly before doing a checkin (see below). If you are unfamiliar with Checkstyle or PMD, please see http://checkstyle.sourceforge.net/ and http://pmd.sourceforge.net/. Consistent formatting makes it easier for others to follow and allows diffs to work properly.
  • Always include the Apache License Headers on all files and the following version tag:
@version $Rev$ $Date$
  • It is expected that code checked in be accompanied by at least unit tests or verified by existing unit tests. Integration tests when appropriate are also helpful.
  • Do not checkin IDE-specific resources such as project files.
  • Prior to check-in, perform a clean build and run the complete battery of unit tests for the current module from the command line with Checkstyle enabled, as in:
mvn clean
mvn -o -Psourcecheck
  • Please do not perform a checkin using an IDE as doing so is frequently problematic.
  • Include a descriptive log message for checkins, i.e. not, "fixed some stuff".

Testing Standards

It is expected checkins always be accompanied by unit test and integration tests when appropriate. Unit tests should verify specific behavior relating to a single class or small set of related classes; intergation tests verify code paths across subsystems. Testcases should be documented and clearly indicate what they verify. Also, avoid things that may cause side-effects when possible such as access of external resources.

We encourage and follow continuous integration. Martin Fowler has a concise write-up here

We have found EasyMock extremely useful for unit testing and have standardized on it.

When writing integration tests, use the Maven Integration Test Plugin

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