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| author |  gmcdonald | 2010-02-13 01:32:03 +0000 |
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| committer | gmcdonald | 2010-02-13 01:32:03 +0000 |
| commit | 0425aadc78680e53000fd0108b540d6eca048516 (patch) | |
| tree | 8ec7ab8e015d454c5ec586dfc91e05a2dce1cfc0 /xdocs/docs/architecture_notes.html | |
| download | axis2c-0425aadc78680e53000fd0108b540d6eca048516.tar.gz axis2c-0425aadc78680e53000fd0108b540d6eca048516.tar.bz2 | |
Moving axis svn, part of TLP move INFRA-2441
git-svn-id: http://svn.apache.org/repos/asf/axis/axis2/c/core/trunk@909681 13f79535-47bb-0310-9956-ffa450edef68
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diff --git a/xdocs/docs/architecture_notes.html b/xdocs/docs/architecture_notes.html new file mode 100644 index 0000000..27529d4 --- /dev/null +++ b/xdocs/docs/architecture_notes.html @@ -0,0 +1,76 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html><head><title>Apache Axis2/C - Architecture Notes</title><h2>C Specific Architectural Notes on Apache Axis2/C</h2><p>Please send your feedback to: <a href="mailto:axis-c-dev@ws.apache.org?subject=[Axis2]">axis-c-dev@ws.apache.org</a> +(Subscription details are available on the <a href="http://ws.apache.org/axis2/c/mail-lists.html" class="externalLink" title="External Link">Axis2 site</a>.) Prefix +the subject with [Axis2].</p><div class="subsection"><a name="Contents"></a><h3>Contents</h3><ul> + <li><a href="#Introduction">Introduction</a></li> + <li><a href="#Axis2_Environment">Environment Struct</a></li> + <li><a href="#Dynamic_Loading">Dynamic Loading</a></li> + <li><a href="#Transport_Abstraction">Transport Abstraction</a></li> + <li><a href="#Stream_Abstraction">Stream Abstraction</a></li> + <li><a href="#Threading_Model">Threading Model</a></li> + <li><a href="#Parser_Abstraction">Parser Abstraction</a></li> +</ul><p><a name="Introduction"></a></p></div><div class="subsection"><a name="Introduction"></a><h3>Introduction</h3><p>Some of the main design goals of Apache Axis2/C are the usability of the +library, the ability to be plugged into different platforms, and the ability +to be embedded in other software systems to provide Web services support. +There are many features that allow Axis2/C to be pluggable into different +platforms as well as to enable the extension of the functionality of +Axis2/C.</p><p><a name="Axis2_Environment"></a></p></div><div class="subsection"><a name="Environment_Struct"></a><h3>Environment Struct</h3><p>Apache Axis2/C defines an environment struct to hold platform specific +entities such as the memory allocator, the threading mechanism, etc. The +environment is initialized at the point of starting Axis2/C and will last for +the lifetime of the Axis2/C run-time. Different sub environments can also be +created to suit particular needs, for example, each thread can create its own +environment. The Axis2 environment holds the following entities in order to +abstract the platform specific implementations.</p></div><div class="subsection"><a name="Allocator"></a><h3>Allocator</h3><p>Allocator is the wrapper for memory management mechanisms. It defines the +following primitives:</p><ol> + <li><code>malloc</code> - method to allocate a memory block of a given + size.</li> + <li><code>free</code> - method to free a memory block.</li> +</ol><p>Based on the platform, or the software system into which Axis2/C is +embedded, these primitives could be provided with concrete +implementations.</p></div><div class="subsection"><a name="Error"></a><h3>Error</h3><p>Error defines error reporting mechanisms for Axis2/C. All the Axis2/C +internal functions use the <code>axutil_error</code> struct instance in the +environment to report errors.</p></div><div class="subsection"><a name="Log"></a><h3>Log</h3><p>The log defines the common logging mechanisms required for the Axis2/C +library. All internal Axis2/C code use the functions associated with the +<code>axutil_log</code> struct available in the environment for logging.</p></div><div class="subsection"><a name="Thread_Pool"></a><h3>Thread Pool</h3><p>The thread pool defines the thread management functions. It hides the +complex thread pooling functions as well as the platform specific +implementations of threads. The Axis2/C internal library uses this interface +to manipulate threads and deal with a common thread type which is defined as +<code>axutil_thread.</code></p><p>The environment struct is the starting point for platform abstraction +supported by Axis2/C. It can be used to plug platform specific memory +management, error reporting, logging, and thread pooling mechanisms.</p><p><a name="Dynamic_Loading"></a></p></div><div class="subsection"><a name="Dynamic_Loading"></a><h3>Dynamic Loading</h3><p>Axis2/C is designed in an extensible manner, so that the users can add +functionality by implementing new modules. These modules should be compiled +as Dynamic Shared Objects (DSOs). Services are also loaded dynamically at +server start up by reading the contents of the services folder and service +configuration files.</p><p>The DSO support for loading Axis2/C services and modules is based on the +struct named <code>axutil_class_loader</code>. To abstract the +<code>axutil_class_loader</code> from the DSO loading functionality of the +underlying operating system, a set of platform independent macros such as +<code>AXIS2_PLATFORM_LOADLIB</code> and <code>AXIS2_PLATFORM_UNLOADLIB</code> +are used. These macros will be mapped to platform specific system calls in +platform specific header files (e.g. <code>axutil_unix.h</code> and +<code>axutil_windows.h</code>). The file +<code>axutil_platform_auto_sense.h</code> will include the correct platform +specific header file, based on the compiler directives available at compile +time.</p><p><a name="Transport_Abstraction"></a></p></div><div class="subsection"><a name="Transport_Abstraction"></a><h3>Transport Abstraction</h3><p>One of the key advantages of Axis2/C is the fact that the engine and the +SOAP processing is independent of the transport aspects. Users can develop +their own transports and the interface will be defined in: +<code>axis2_transport_sender.h</code> and +<code>axis2_transport_receiver.h</code>.</p><p>Currently, Axis2/C supports HTTP transport. Axis2/C Apache2 module (<a href="installationguide.html#installing-apache2">mod_axis2</a>) is an example +of the implementation of the <code>axis2_transport_receiver.h</code> +interface. libcurl based client transport is an example of the implementation +of the <code>axis2_transport_sender.h</code> interface.</p><p><a name="Stream_Abstraction"></a></p></div><div class="subsection"><a name="Stream_Abstraction"></a><h3>Stream Abstraction</h3><p>Stream is a representation of a sequence of bytes. Since Axis2/C heavily +uses streaming mechanisms to read/write XML, an implementation independent +stream abstraction is required in order to integrate Axis2/C into other +environments seamlessly. The core components of Axis2/C deal with this +abstracted stream and does not worry about the implementation specific +details. <code>axutil_stream.h</code> defines the stream interface.</p><p><a name="Threading_Model"></a></p></div><div class="subsection"><a name="Threading_Model"></a><h3>Threading Model</h3><p>The Axis2/C core functions such as asynchronous invocation and concurrent +request processing in simple axis2 server make use of threads. The use of +threads should be platform independent inside the Axis2/C core components.</p><p>An implementation independent interface for threads is provided in the +<code>axutil_thread.h</code> header file. Platform specific implementations +of this interface are provided for Windows and Linux.</p><p><a name="Parser_Abstraction"></a></p></div><div class="subsection"><a name="Parser_Abstraction"></a><h3>Parser Abstraction</h3><p>The Axis2/C architecture depends on the XML pull model when dealing with +XML payloads. In Java there is StAX API, but in C there is no such standard +API. Therefore, an XML pull API, that is similar to StAX API, is defined in +the <code>axiom_xml_reader.h</code> and <code>axiom_xml_writer.h</code>. Any +implementation of this API can be plugged into the Axis2/C core. If an +external XML parser needs to be plugged into Axis2/C, a wrapper that maps the +reading/writing functions to the Axis2/C XML reader/writer API should be +written.</p></div></div></div></div><div class="clear"><hr></hr></div></body></html> |