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diff --git a/site/trunk/site-publish/java-sca-overview.html b/site/trunk/site-publish/java-sca-overview.html new file mode 100644 index 0000000000..afd797d376 --- /dev/null +++ b/site/trunk/site-publish/java-sca-overview.html @@ -0,0 +1,196 @@ + +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> +<HTML> + <HEAD> + <LINK type="text/css" rel="stylesheet" href="resources/space.css"> + <STYLE type="text/css"> + .footer { + background-image: url('http://cwiki.apache.org/confluence/images/border/border_bottom.gif'); + background-repeat: repeat-x; + background-position: left top; + padding-top: 4px; + color: #666; + } + </STYLE> + <SCRIPT type="text/javascript" language="javascript"> + var hide = null; + var show = null; + var children = null; + + function init() { + /* Search form initialization */ + var form = document.forms['search']; + if (form != null) { + form.elements['domains'].value = location.hostname; + form.elements['sitesearch'].value = location.hostname; + } + + /* Children initialization */ + hide = document.getElementById('hide'); + show = document.getElementById('show'); + children = document.all != null ? 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The kernel is essentially a multi-VM wiring engine that connects components together using the principles of <SPAN class="nobr"><A href="http://en.wikipedia.org/wiki/Dependency_injection" title="Visit page outside Confluence" rel="nofollow">Dependency Injection<SUP><IMG class="rendericon" src="http://cwiki.apache.org/confluence/images/icons/linkext7.gif" height="7" width="7" align="absmiddle" alt="" border="0"></SUP></A></SPAN>, or <SPAN class="nobr"><A href="http://en.wikipedia.org/wiki/Inversion_of_control" title="Visit page outside Confluence" rel="nofollow">Inversion of Control<SUP><IMG class="rendericon" src="http://cwiki.apache.org/confluence/images/icons/linkext7.gif" height="7" width="7" align="absmiddle" alt="" border="0"></SUP></A></SPAN>.</P> + +<H3><A name="JavaSCAOverview-Kernel"></A>Kernel</H3> + +<P>The kernel is designed to be simple and limited in its capabilities: it wires functional units together. Capabilities such as service discovery, reliability, support for transport protocols, etc. are provided through extensions. The kernel extension model is based on the SCA 1.0 Java programming and assembly model. In otherwords, the kernel uses SCA to bootstrap itself. The mechanics of how this is done are described in detail elsewhere <SPAN class="nobr"><A href="http://cwiki.apache.org/confluence/pages/createpage.action?spaceKey=TUSCANY&title=Kernel%20Architecture&linkCreation=true&fromPageId=47661" title="Create Page: Kernel Architecture" class="createlink">Kernel Architecture<SUP><IMG class="rendericon" src="http://cwiki.apache.org/confluence/images/icons/plus.gif" height="7" width="7" align="absmiddle" alt="" border="0"></SUP></A></SPAN>. </P> + +<P>The kernel is divided into a number of modules: <EM>api</EM>, <EM>host_api</EM>, <EM>spi</EM> and <EM>core</EM>. The <EM>api</EM> module defines Tuscany proprietary programming model annotations and APIs. The <EM>host_api</EM> module defines APIs for interacting with the kernel. The <EM>spi</EM> module defines extension points and abstract helper classes. The <EM>core</EM> module contains the kernel implementation. </P> + +<H3><A name="JavaSCAOverview-Extensions"></A>Extensions</H3> + +<P>Extensions enhance the kernel with specific sets of functionality. Extension types are not fixed and the kernel is designed to be as flexible as possible by providing an open-ended extension model. From the kernel perspective, extensions are just a set of SCA components. However, there are a number of known extension types defined by the <EM>spi</EM> module, including:</P> + +<UL> + <LI><B>Component implementation types</B>, e.g. Spring, Groovy, and JavaScript</LI> + <LI><B>Binding types</B>, e.g. Axis, CXF, AMQP, ActiveMQ, JXTA</LI> + <LI><B>DataBinding types</B>, e.g. JAXB, SDO, XmlBeans</LI> +</UL> + + +<P>There are also a number of add-on extensions that do not correspond to a well-know type:</P> + +<UL> + <LI>The JPA extension for O/R mapping</LI> + <LI>The Geronimo Transaction Manager extension for transactional support in the runtime</LI> + <LI>The HOWL-based Persistent Store extension for high-throughput persistence of conversational state</LI> +</UL> + + +<P>More detail can be found in the <SPAN class="nobr"><A href="http://cwiki.apache.org/confluence/pages/createpage.action?spaceKey=TUSCANY&title=Extensions%20Guide&linkCreation=true&fromPageId=47661" title="Create Page: Extensions Guide" class="createlink">Extensions Guide<SUP><IMG class="rendericon" src="http://cwiki.apache.org/confluence/images/icons/plus.gif" height="7" width="7" align="absmiddle" alt="" border="0"></SUP></A></SPAN> section, but a few high-level best practices for designing extensions are listed here:</P> + +<UL> + <LI>Make sure you are familiar with SCA 1.0 Assembly and the SCA Java 1.0 programming model. Specifications can be found at <SPAN class="nobr"><A href="http://cwiki.apache.org/confluence/pages/createpage.action?spaceKey=TUSCANY&title=www.osoa.org&linkCreation=true&fromPageId=47661" title="Create Page: www.osoa.org" class="createlink">www.osoa.org<SUP><IMG class="rendericon" src="http://cwiki.apache.org/confluence/images/icons/plus.gif" height="7" width="7" align="absmiddle" alt="" border="0"></SUP></A></SPAN>.</LI> +</UL> + + +<UL> + <LI>Never reference any classes in <EM>core</EM>. These classes are implementation-specific and subject to change; they are not part of the public SPI contract.</LI> +</UL> + + +<UL> + <LI>Use autowire when assembling extension components.</LI> +</UL> + + +<UL> + <LI>Do not mess with classloaders such as setting the current context classloader unless it is absolutely necessary, i.e. a library used by an extension makes assumptions about context classloaders. Ideally the library can be refactored to not make these assumptions. If not, make sure the extension properly resets the current context classloader.</LI> +</UL> + + +<UL> + <LI>Preferrably use <SPAN class="nobr"><A href="http://cwiki.apache.org/confluence/pages/createpage.action?spaceKey=TUSCANY&title=www.easymock.org&linkCreation=true&fromPageId=47661" title="Create Page: www.easymock.org" class="createlink">EasyMock<SUP><IMG class="rendericon" src="http://cwiki.apache.org/confluence/images/icons/plus.gif" height="7" width="7" align="absmiddle" alt="" border="0"></SUP></A></SPAN> for mocking kernel functionality during extension unit testing.</LI> +</UL> + + +<UL> + <LI>Use the <SPAN class="nobr"><A href="http://cwiki.apache.org/confluence/pages/createpage.action?spaceKey=TUSCANY&title=Tuscany%20iTest%20Plugin%20Maven%2BPlugins&linkCreation=true&fromPageId=47661" title="Create Page: Tuscany iTest Plugin Maven+Plugins" class="createlink">Tuscany iTest Plugin Maven+Plugins<SUP><IMG class="rendericon" src="http://cwiki.apache.org/confluence/images/icons/plus.gif" height="7" width="7" align="absmiddle" alt="" border="0"></SUP></A></SPAN> for integration testing the extension.</LI> +</UL> + + +<UL> + <LI>Preferrably use <SPAN class="nobr"><A href="http://cwiki.apache.org/confluence/pages/createpage.action?spaceKey=TUSCANY&title=www.easymock.org&linkCreation=true&fromPageId=47661" title="Create Page: www.easymock.org" class="createlink">EasyMock<SUP><IMG class="rendericon" src="http://cwiki.apache.org/confluence/images/icons/plus.gif" height="7" width="7" align="absmiddle" alt="" border="0"></SUP></A></SPAN> for mocking kernel functionality during extension unit testing.</LI> +</UL> + + +<UL> + <LI>Use the <SPAN class="nobr"><A href="http://cwiki.apache.org/confluence/pages/createpage.action?spaceKey=TUSCANY&title=Tuscany%20iTest%20Plugin%20Maven%2BPlugins&linkCreation=true&fromPageId=47661" title="Create Page: Tuscany iTest Plugin Maven+Plugins" class="createlink">Tuscany iTest Plugin Maven+Plugins<SUP><IMG class="rendericon" src="http://cwiki.apache.org/confluence/images/icons/plus.gif" height="7" width="7" align="absmiddle" alt="" border="0"></SUP></A></SPAN> for integration testing the extension.</LI> +</UL> + + +<H3><A name="JavaSCAOverview-Runtimes"></A>Runtimes</H3> + +<P>The kernel is designed to be embedded in, or provisioned to, a number of different host environments. For example, the kernel may be provisioned to an OSGi container, a standalone runtime, a servlet engine, or JEE application server. There is even a Maven runtime that embeds kernel for integration testing. Runtime capabilities may vary based on the host environment. </P> + + + + </DIV> + + + </DIV> + </DIV> + <DIV class="footer"> + Generated by + <A href="http://www.atlassian.com/confluence/">Atlassian Confluence</A> (Version: 2.2.9 Build: 527 Sep 07, 2006) + <A href="http://could.it/autoexport/">AutoExport Plugin</A> (Version: Unknown - PluginManager Error) + </DIV> + </BODY> +</HTML>
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