Author: vanto
Date: Fri Nov 23 09:48:17 2012
New Revision: 1412801
URL: http://svn.apache.org/viewvc?rev=1412801&view=rev
Log:
CMS commit to ode by vanto
Modified:
ode/site/trunk/content/bpel-extensions.mdtext
Modified: ode/site/trunk/content/bpel-extensions.mdtext
URL:
http://svn.apache.org/viewvc/ode/site/trunk/content/bpel-extensions.mdtext?rev=1412801&r1=1412800&r2=1412801&view=diff
==============================================================================
--- ode/site/trunk/content/bpel-extensions.mdtext (original)
+++ ode/site/trunk/content/bpel-extensions.mdtext Fri Nov 23 09:48:17 2012
@@ -1,31 +1,33 @@
Title: BPEL Extensions
+
+# Overview
ODE extends the [WS-BPEL](ws-bpel-2.0.html) in areas that aren't covered by
the spec. This page details these extensions.
- * [[Implicit Correlations]](#BPELExtensions-[ImplicitCorrelations])
- * [[Activity Failure and
Recovery]](#BPELExtensions-[ActivityFailureandRecovery])
- * [[Extension Activities & Extensible Assign
Operations]](#BPELExtensions-[ExtensionActivities&ExtensibleAssignOperations])
- * [[XPath Extensions]](#BPELExtensions-[XPathExtensions])
- * [[External Variables]](#BPELExtensions-[ExternalVariables])
- * [[Headers Handling]](#BPELExtensions-[HeadersHandling])
- * [[RESTful BPEL, Part I]](#BPELExtensions-[RESTfulBPEL,PartI])
- * [[RESTful BPEL, Part II]](#BPELExtensions-[RESTfulBPEL,PartII])
- * [[Iterable ForEach]](#BPELExtensions-[IterableForEach])
- * [[Flexible Assigns]](#BPELExtensions-[FlexibleAssigns])
- * [[Process Contexts]](#BPELExtensions-[ProcessContexts])
+ * [Implicit Correlations](#BPELExtensions-ImplicitCorrelations)
+ * [Activity Failure and
Recovery](#BPELExtensions-ActivityFailureandRecovery)
+ * [Extension Activities & Extensible Assign
Operations](#BPELExtensions-ExtensionActivities-ExtensibleAssignOperations)
+ * [XPath Extensions](#BPELExtensions-XPathExtensions)
+ * [External Variables](#BPELExtensions-ExternalVariables)
+ * [Headers Handling](#BPELExtensions-HeadersHandling)
+ * [RESTful BPEL, Part I](#BPELExtensions-RESTfulBPEL,PartI)
+ * [RESTful BPEL, Part II](#BPELExtensions-RESTfulBPEL,PartII)
+ * [Iterable ForEach](#BPELExtensions-IterableForEach)
+ * [Flexible Assigns](#BPELExtensions-FlexibleAssigns)
+ * [Process Contexts](#BPELExtensions-ProcessContexts)
-<a name="BPELExtensions-[ImplicitCorrelations](implicitcorrelations.html)"></a>
-## [Implicit Correlations]
+<a name="BPELExtensions-ImplicitCorrelations"></a>
+## [Implicit Correlations](implicitcorrelations.html)
-BPEL process instances are stateful â therefore, a client interacting with
the BPEL engine must identify the particular instance with which it intends to
interact in all of its communications. The BPEL specification defines a
mechanism â _correlation_ â which allows the process designer to specify
which parts of an incoming message (i.e. a message going from a client to the
BPEL server) should be used to identify the target process instance.
Correlation is a powerful mechanism â however it is a bit complicated and
relies on "in-band" message data to associate a messages with a process
instance.
+BPEL process instances are stateful â therefore, a client interacting with
the BPEL engine must identify the particular instance with which it intends to
interact in all of its communications. The BPEL specification defines a
mechanism â *correlation* â which allows the process designer to specify
which parts of an incoming message (i.e. a message going from a client to the
BPEL server) should be used to identify the target process instance.
Correlation is a powerful mechanism â however it is a bit complicated and
relies on "in-band" message data to associate a messages with a process
instance.
-To keep simple cases simple, ODE provides an alternative correlation mechanism
â _implicit correlation_ â that automatically handles correlation through
"out-of-band" session identifiers. The mechanism is simple: a unique session
identifier is associated with every every partner link instance. When a message
is sent on a partner link, the session identifier is sent along with the
message. The recipient is then able to use the received session identifier in
subsequent communications with the process instance. Messages received by the
BPEL engine that have a session identifier are routed to the correct instance
(and partner link) by that session identifier.
+To keep simple cases simple, ODE provides an alternative correlation mechanism
â *implicit correlation* â that automatically handles correlation through
"out-of-band" session identifiers. The mechanism is simple: a unique session
identifier is associated with every every partner link instance. When a message
is sent on a partner link, the session identifier is sent along with the
message. The recipient is then able to use the received session identifier in
subsequent communications with the process instance. Messages received by the
BPEL engine that have a session identifier are routed to the correct instance
(and partner link) by that session identifier.
[Read more](implicit-correlations.html)
-<a
name="BPELExtensions-[ActivityFailureandRecovery](activityfailureandrecovery.html)"></a>
-## [Activity Failure and Recovery]
+<a name="BPELExtensions-ActivityFailureandRecovery"></a>
+## [Activity Failure and Recovery](activityfailureandrecovery.html)
-There are several types of error conditions. In this document we introduce a
class of error condition called _failures_, distinct from _faults_, and
describe how failures are caught and handled by the process engine.
+There are several types of error conditions. In this document we introduce a
class of error condition called *failures*, distinct from *faults*, and
describe how failures are caught and handled by the process engine.
For example, when the process is unable to perform DNS resolution to determine
the service endpoint, it generates a failure. An administrator can fix the DNS
server and tell the process engine to retry the activity. Had the DNS error
been reported as a fault, the process would either terminate or require complex
fault handling and recovery logic to proceed past this point of failure.
@@ -33,66 +35,65 @@ In short, failures shields the process f
[Read more](activity-failure-and-recovery.html)
-<a
name="BPELExtensions-[ExtensionActivities&ExtensibleAssignOperations](extensionactivities&extensibleassignoperations.html)"></a>
-## [Extension Activities & Extensible Assign Operations]
+<a name="BPELExtensions-ExtensionActivities-ExtensibleAssignOperations"></a>
+## [Extension Activities & Extensible Assign
Operations](extensionactivities-extensibleassignoperations.html)
Apache ODE provides a plug-in architecture for custom activity implementations
and custom variable assignment logic. Such plug-ins can be registered to ODE
and can be used according to the WS-BPEL 2.0 extensibility mechnisms
(`<extensionActivity>` & `<extensionAssignOperation>`).
[Read more](extension-activities-&-extensible-assign-operations.html)
-<a name="BPELExtensions-[XPathExtensions](xpathextensions.html)"></a>
-## [XPath Extensions]
+<a name="BPELExtensions-XPathExtensions"></a>
+## [XPath Extensions](xpathextensions.html)
Apache ODE extends the default XPath coverage provided by the WS-BPEL
specification mostly by adding support for [XPath
2.0](http://www.w3.org/TR/xpath20/) and by offering a few utility extension
functions to make some assignments easier.
[Read more](xpath-extensions.html)
-<a name="BPELExtensions-[ExternalVariables](externalvariables.html)"></a>
-## [External Variables]
+<a name="BPELExtensions-ExternalVariables"></a>
+## [External Variables](externalvariables.html)
External variables are an easy way to share data between the process and
external systems, by treating those independent entities as BPEL variables that
can be used in expressions and assignments. External variables may be records
stored in the database, REST resources, etc.
[Read more](external-variables.html)
-<a name="BPELExtensions-[HeadersHandling](headershandling.html)"></a>
-## [Headers Handling]
+<a name="BPELExtensions-HeadersHandling"></a>
+## [Headers Handling](headershandling.html)
There are several situations where one would want to access headers form the
wire format in their BPEL process. It could be to assign them to another
message and pass them around or to execute some business logic that's
header-dependent (often a bad idea but sometimes there's no choice). ODE
supports the manipulation of wire format headers in two different ways.
[Read more](headers-handling.html)
-<a name="BPELExtensions-[RESTfulBPEL,PartI](restfulbpel,parti.html)"></a>
-## [RESTful BPEL, Part I]
+<a name="BPELExtensions-RESTfulBPEL,PartI"></a>
+## [RESTful BPEL, Part I](restfulbpel,parti.html)
Extends the invoke activity to handle RESTful Web services. This extension
uses BPEL variables of type xsd:uri and xsd:string instead of partner links,
and does away with the WSDL indirection, making it straightforward to develop
processes that use RESTful Web services.
[Read more](restful-bpel,-part-i.html)
-<a name="BPELExtensions-[RESTfulBPEL,PartII](restfulbpel,partii.html)"></a>
-## [RESTful BPEL, Part II]
+<a name="BPELExtensions-RESTfulBPEL,PartII"></a>
+## [RESTful BPEL, Part II](restfulbpel,partii.html)
Extends receive and onEvent to expose RESTful resources that. This extension
adds the ability to declare and instantiate resources, and specific handling
for the HTTP methods GET, POST, PUT and DELETE.
[Read more](restful-bpel,-part-ii.html)
-<a name="BPELExtensions-[IterableForEach](iterableforeach.html)"></a>
-## [Iterable ForEach]
+<a name="BPELExtensions[IterableForEach"></a>
+## [Iterable ForEach](iterableforeach.html)
Extends the <forEach> activity so that the counter variable iterates over the
items contained in a given sequence. This extension provides an alternative
and more dynamic way of generating M branches, where M is the size of the
binding sequence. The semantics of the <completionCondition> stays the same, in
that the loop is deemed to be complete if B out of the M branches complete
(successfully), where B is its actual value.
[Read more](iterable-foreach.html)
-<a name="BPELExtensions-[FlexibleAssigns](flexibleassigns.html)"></a>
-## [Flexible Assigns]
+<a name="BPELExtensions-FlexibleAssigns"></a>
+## [Flexible Assigns](flexibleassigns.html)
Extends the <assign> activity so that it can be made to either ignore or
insert data that is missing in the to-spec of a copy operation. This shortcut
allows users to handle what would normally be fault scenarios, in a more
graceful and intuitive way.
[Read more](flexible-assigns.html)
-<a name="BPELExtensions-[ProcessContexts](processcontexts.html)"></a>
-## [Process Contexts]
+<a name="BPELExtensions-ProcessContexts"></a>
+## [Process Contexts](processcontexts.html)
Extends BPEL and ODE to allow the circulation of transport metadata (like
security tokens, correlation keys, or tracing informations) from messages to
processes and then from processes to messages.
[Read more](process-contexts.html)
-
