Author: ate
Date: Mon Mar 10 22:33:20 2014
New Revision: 1576109
URL: http://svn.apache.org/r1576109
Log:
Adding SCXML 2.0 roadmap documentation
Added:
commons/proper/scxml/trunk/src/site/xdoc/roadmap.xml (with props)
Modified:
commons/proper/scxml/trunk/src/site/site.xml
commons/proper/scxml/trunk/src/site/xdoc/index.xml
Modified: commons/proper/scxml/trunk/src/site/site.xml
URL:
http://svn.apache.org/viewvc/commons/proper/scxml/trunk/src/site/site.xml?rev=1576109&r1=1576108&r2=1576109&view=diff
==============================================================================
--- commons/proper/scxml/trunk/src/site/site.xml (original)
+++ commons/proper/scxml/trunk/src/site/site.xml Mon Mar 10 22:33:20 2014
@@ -27,6 +27,9 @@
<item name="Overview"
href="/index.html"/>
+ <item name="Roadmap"
+ href="/roadmap.html"/>
+
<item name="User Guide"
href="/guide.html"
collapse="true">
Modified: commons/proper/scxml/trunk/src/site/xdoc/index.xml
URL:
http://svn.apache.org/viewvc/commons/proper/scxml/trunk/src/site/xdoc/index.xml?rev=1576109&r1=1576108&r2=1576109&view=diff
==============================================================================
--- commons/proper/scxml/trunk/src/site/xdoc/index.xml (original)
+++ commons/proper/scxml/trunk/src/site/xdoc/index.xml Mon Mar 10 22:33:20 2014
@@ -28,11 +28,11 @@
<section name="Commons SCXML">
<p>
- <a href="http://www.w3.org/TR/scxml/";>State Chart XML (SCXML)</a> is
currently a
- Working Draft published by the World Wide Web Consortium (W3C).
+ <a href="http://www.w3.org/TR/scxml/"; target="_blank">State Chart XML
(SCXML)</a> is currently a
+ Candidate Recommendation published by the World Wide Web Consortium (W3C).
SCXML provides a generic state-machine based execution environment based on
Harel
State Tables. SCXML is a candidate for the control language within
- multiple markup languages coming out of the W3C (see Working Draft for
details).
+ multiple markup languages coming out of the W3C (see Candidate
Recommendation for details).
<em>Commons SCXML</em> is an implementation aimed at creating
and maintaining a Java SCXML engine capable of executing a state machine
defined
using a SCXML document, while abstracting out the environment interfaces.
@@ -50,6 +50,16 @@
</section>
+ <section name="Commons SCXML 2.0 Roadmap">
+ <p>
+ The current development for Commons SCXML is targeted towards a 2.0
release which will be aligned and compliant
+ with the SCXML specification.
+ </p>
+ <p>
+ A high-level overview of the technical and functional changes needed
towards this goal are available on the
+ <a href="roadmap.html">Commons SCXML 2.0 Roadmap</a>.
+ </p>
+ </section>
<section name="Documentation">
<p>
@@ -70,7 +80,6 @@
</p>
</section>
-
<section name="Releases">
<p>
The latest release is v0.9. Read
Added: commons/proper/scxml/trunk/src/site/xdoc/roadmap.xml
URL:
http://svn.apache.org/viewvc/commons/proper/scxml/trunk/src/site/xdoc/roadmap.xml?rev=1576109&view=auto
==============================================================================
--- commons/proper/scxml/trunk/src/site/xdoc/roadmap.xml (added)
+++ commons/proper/scxml/trunk/src/site/xdoc/roadmap.xml Mon Mar 10 22:33:20
2014
@@ -0,0 +1,216 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+-->
+<document>
+ <properties>
+ <title>Commons SCXML Roadmap</title>
+ <author email="[email protected]">Commons Documentation Team</author>
+ </properties>
+ <body>
+ <section name="Commons SCXML 2.0 Roadmap">
+ <p>
+ The last SCXML release 0.9 has been quite some time ago (2008) and
since then the
+ <a href="http://www.w3.org/TR/scxml/"; target="_blank">W3C SCXML
specification</a>, as of 11 March 2014 a
+ <em>"Candidate Recommendation"</em>, has progressed and changed quite
a lot.
+ </p>
+ <p>
+ The goal for Commons SCXML 2.0 is to get alignment (back) and be
compliant with the W3C SCXML specification,
+ but for this a lot of major changes are needed, both to the 'public'
API and, even more so, to the internal
+ model and processing logic.
+ </p>
+ <p>
+ To be able to make such major changes in an effective way, we already
cleaned out a lot of the old but no
+ longer relevant, working or otherwise compatible features from the
previous SCXML (0.9) version, see
+ <a href="#Milestone_0:_Cleanup_(done)">Milestone 0</a> below.
+ </p>
+ <p>
+ The work needed towards Commons SCXML 2.0 has been divided in a set of
high-level targets and corresponding
+ milestones:
+ </p>
+ <subsection name="Milestone 0: Cleanup (done)">
+ <p>
+ The first and already completed target was to cleanup and clean out
no longer relevant or even no longer
+ working features, or features which would make it very hard or
complicated to keep working and supported
+ for the major changes ahead.
+ </p>
+ <p>
+ The support for the following features and integrations has been
dropped: Shale/JSF, Rhino/E4X, Servlet/JSP.
+ </p>
+ <p>
+ Note: some of the dropped features <em>might</em> be restored or
re-implemented again once we reached a
+ reasonable level of stability for the new APIs and internal logic,
but that also will depend on the level of
+ interest and support from the community.
+ </p>
+ <p>
+ Technically, this milestone 0 still is largely compatible with the
0.9 release,
+ just without those above mentioned features, and also now requires
Java 6+. In addition this milestone also
+ contains several fixes and enhancements (like Groovy language
support).
+ </p>
+ </subsection>
+ <subsection name="Milestone 1: Redesign semantics and processing
components">
+ <p>
+ The target for milestone 1 is a redesign and better separation of
concerns of the main SCXML processing
+ components: SCXMLSemantics, SCXMLExecutor and SCInstance.
+ </p>
+ <p>
+ The high-level plan is to:
+ <ul>
+ <li>Redefine SCXMLSemantics to align with the
+ <a
href="http://www.w3.org/TR/scxml/#AlgorithmforSCXMLInterpretation";
target="_blank">
+ SCXML Algorithm for SCXML Interpretation</a>
+ <p>
+ The current SCXMLSemantics interface and its implementation is
so much different from
+ the algorithm in the specification that 'molding' it into what
the algorithm now expects is too
+ cumbersome.
+ </p>
+ <p>
+ Also, developers wishing to extend or customize the
SCXMLSemantics will have a hard time to match that
+ against the algorithm as well.
+ </p>
+ <p>
+ The intend therefore is to start with a new SCXMLSemantics
interface from scratch which (largely)
+ follows the algorithm in the specification.
+ </p>
+ </li>
+ <li>
+ Better separation of concern between SCXMLExecutor and
SCInstance.
+ <p>
+ The purpose of SCInstance is to be used as backing store for
internal SCXML state. However
+ over time some processing and transient state based features
have ended up in SCInstance which are more
+ appropriated to be managed by the SCXMLExecutor instead.
+ </p>
+ <p>
+ Conversely, SCXMLExecutor maintains the current Status for the
SCXML state as well as the internal
+ events list going with it. Having the Status, without the
processing related events list, to be
+ managed by SCInstance instead would be better fitting.
+ </p>
+ <p>
+ And finally, SCXMLExecutor currently doesn't yet provide a
good abstraction or implementation of the
+ <a href="http://www.w3.org/TR/scxml/#SCXMLEventProcessor";
target="_blank">
+ SCXML Event I/O Processor</a> functionally.
+ The internal and external event I/O management is a critical
requirement and many features of the
+ specification rely on it fulfilling this contract.<br/>
+ The goal for this milestone is to provide a least a basic
level of support for the SCXML Event I/O
+ Processor and Event queue handling features.<br/>
+ </p>
+ <p>
+ Overall, the intend is to let SCXMLExecutor be responsible as
SCXML Processor and SCXML I/O Processor
+ and to maintain all transient processing state including the
system variables, while delegating to
+ SCXMLSemantics for dealing with the processing algorithm.
+ </p>
+ </li>
+ </ul>
+ </p>
+ </subsection>
+ <subsection name="Milestone 2: Datamodel and data manipulation
alignment">
+ <p>The target for milestone 2 is to get better alignment with the
SCXML datamodel specification.</p>
+ <p>
+ The Commons SCXML datamodel and context features are very flexible
and can be defined and redefined in a
+ hierarchical way (per state element). However this also makes it
much more complex to manage, especially for
+ XPath (XML) datamodel definitions.
+ </p>
+ <p>
+ The SCXML specification however is very explicit in its requirements
that, while datamodel elements may be
+ defined in multiple locations within an SCXML document, together
they must be accessible (and thus managed) as
+ a single datamodel definition.
+ </p>
+ <p>
+ The current Commons SCXML datamodel (and the backing Context
handling) is to some extend actually more
+ flexible and generic than what is possible <em>AND</em> allowed by
the specification.
+ </p>
+ <p>
+ To be able to be compliant with the specification, the
<em>default</em> datamodel management in
+ Commons SCXML will have to be more restricted and simplified.<br/>
+ That will actually make things much easier to implement. For an
XPath (XML) datamodel then only a single
+ (aggregated) XML datamodel document can be used and the custom
Commons SCXML Data() function no longer will be
+ needed to access the data elements.
+ </p>
+ <p>
+ It is the intend to also retain the current flexible Commons SCXML
datamodel and context features, but
+ provide this as custom extension, no longer as default.
+ </p>
+ </subsection>
+ <subsection name="Milestone 3: SCXML model alignment">
+ <p>
+ The target for milestone 3 is to complete the support for the
remaining SCXML model elements.
+ </p>
+ <p>
+ The current Commons SCXML is still missing implementation of some
SCXML element features, or is providing
+ functionality or behavior not compliant with the specification.
+ </p>
+ </subsection>
+ <subsection name="Milestone 4: Session management, external
communications and environment variables">
+ <p>
+ The target for milestone 4 is to complete the remaining SCXML
Processor and SCXML I/O Processor required
+ features for session management and external communications (send
and invoke elements).
+ </p>
+ <p>
+ There are several requirements and restrictions with respect to
environment variables which also needs to be
+ supported.
+ </p>
+ </subsection>
+ <subsection name="Commons SCXML 2.0 release">
+ <p>
+ If and when all of the above milestone targets are met Commons SCXML
should be very close to being in
+ compliance with the SCXML specification, and/or in any case at a
good enough level for all practical purposes,
+ to be released as Commons SCXML 2.0.
+ </p>
+ <p>
+ As part of validation the implementation, the
+ <a href="http://www.w3.org/Voice/2013/scxml-irp/";
target="_blank">SCXML 1.0 Implementation Report Plan</a>
+ will be used to test against.
+ </p>
+ <p>
+ Even if the IRP is not intended to be used for conformance testing
of implementations, it is very much used as
+ a functional benchmark, also by other SCXML implementations.
+ </p>
+ </subsection>
+ <subsection name="Commons SCXML 2.0+: Optional SCXML features">
+ <p>
+ There are still plenty of optional features in the SCXML
specification which might be very useful to support,
+ like ECMAScript+JSON datamodel or HTTP Event I/O Processor support.
+ </p>
+ <p>
+ Also, adding extensions outside the specification, or bringing back
some of the features dropped for
+ milestone 0, like integration with other frameworks or expression
languages (Servlet, EL, etc.) will be
+ considered again.
+ </p>
+ </subsection>
+
+ <subsection name="Milestone tags">
+ <p>
+ For the above milestones specific VCS milestone tags will be set,
like <b>commons-scxml-2.0-M0</b>.
+ </p>
+ <p>
+ These milestones tag however do <b><em>not</em></b> represent a
formal release and they are
+ <b><em>only</em></b> intended and targeted to be used by the Commons
SCXML developers, not end users.
+ </p>
+ <p>
+ Developers willing to test and validate these milestones can do so
by using the following Maven dependency
+ configuration (using milestone 0 as example):
+ <pre><![CDATA[
+ <dependency>
+ <groupId>org.apache.commons</groupId>
+ <artifactId>commons-scxml2</artifactId>
+ <version>2.0-M0</version>
+ </dependency>]]>
+ </pre>
+ </p>
+ </subsection>
+ </section>
+ </body>
+</document>
\ No newline at end of file
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