craigmcc 01/11/18 20:56:49
Modified: workflow/src/java/org/apache/commons/workflow/core
package.html
Log:
Document a few more Step executions.
Revision Changes Path
1.3 +138 -3
jakarta-commons-sandbox/workflow/src/java/org/apache/commons/workflow/core/package.html
Index: package.html
===================================================================
RCS file:
/home/cvs/jakarta-commons-sandbox/workflow/src/java/org/apache/commons/workflow/core/package.html,v
retrieving revision 1.2
retrieving revision 1.3
diff -u -r1.2 -r1.3
--- package.html 2001/11/18 23:38:51 1.2
+++ package.html 2001/11/19 04:56:49 1.3
@@ -90,8 +90,28 @@
<core:goto step="notOk">
</pre>
+<a name="core:call"></a>
<h3>core:call</h3>
+<p>The <em>core:call</em> Step pops the top value from the evaluation stack,
+which must be an <a href="../Activity.html">Activity</a>, and initiates a
+"subroutine call" to execute this Activity before resuming the current one.
+Control will be returned to the step following this one, once the called
+Activity executes an <a href="#core:exit">core:exit</a> Step, or the last
+defined Step in the Activity has been executed.</p>
+
+<p>In the example below, the <code>activity</code> property of the
+<code>process</code> bean is assumed to return an instance of Activity that
+is to be executed to accomplish a portion of a business process. This allows
+components to manage the overall control flow dynamically.</p>
+<pre>
+ <core:get>
+ <core:descriptor xpath="process/activity"/>
+ </core:get>
+ <core:call>
+</pre>
+
+
<h3>construct</h3>
<h3>duplicate</h3>
@@ -105,12 +125,90 @@
<h3>invoke</h3>
<h3>load</h3>
+
+<a name="notAnd"></a>
+<h3>core:notAnd</h3>
+
+<p>The <em>core:notAnd</em> Step evaluates the properties specified by all
+nested <code><core:descriptor></code> elements, and transfers control
+to the specified step if ALL of them are <code>false</code> (if boolean) or
+null (if Object). To avoid non-deterministic evaluation stack behavior, all of
+the nested <code><core:descriptor> elements are always evaluated.</p>
+
+<p><em>NOTE:</em> - This is the exact opposite of
+<a href="#and">and</a>.</p>
+
+<p>The <em>core:notAnd</em> element recognizes the following attributes:
+<ul>
+<li><strong>id</strong> - Optional identifier of this Step, which can be used
+ as the destination for control transfers. If specified, must be unique
+ within the current Activity.</li>
+<li><strong>step</strong> - Identifier of the Step (within this Activity) to
+ which control should be transferred if the condition is met.</li>
+</ul>
+
+<p>You may nest any number of <a href="#core:descriptor">core:descriptor</a>
+elements within a <em>core:notAnd</em> element. All of them will be evaluated
+in order to determine whether or not a branch to the Step specified by the
+<em>step</em> attribute should occur or not.</p>
+
+<p>In the following example, control will branch to the Step labelled
+<code>empty</code> if all of the specified properties of the
+<code>address</code> bean return null String values. Otherwise, control will
+be transferred (via the <em>core:goto</em> Step) to the Step labelled
+<code>notEmpty</code>.</p>
+<pre>
+ <core:notAnd step="empty">
+ <core:descriptor xpath="address/street1"/>
+ <core:descriptor xpath="address/city"/>
+ <core:descriptor xpath="address/state"/>
+ <core:descriptor xpath="address/zipCode"/>
+ </core:and>
+ <core:goto step="notEmpty">
+</pre>
+
+<a name="core:notOr"></a>
+<h3>core:notOr</h3>
-<h3>notAnd</h3>
+<p>The <em>core:notOr</em> Step evaluates the properties specified by all
+nested <code><core:descriptor></code> elements, and transfers control
+to the specified step if ANY of them are <code>false</code> (if boolean) or
+null (if Object). To avoid non-deterministic evaluation stack behavior, all of
+the nested <code><core:descriptor> elements are always evaluated.</p>
-<h3>notOr</h3>
+<p><em>NOTE:</em> - This is the exact opposite of
+<a href="#or">or</a>.</p>
+<p>The <em>core:notOr</em> element recognizes the following attributes:
+<ul>
+<li><strong>id</strong> - Optional identifier of this Step, which can be used
+ as the destination for control transfers. If specified, must be unique
+ within the current Activity.</li>
+<li><strong>step</strong> - Identifier of the Step (within this Activity) to
+ which control should be transferred if the condition is met.</li>
+</ul>
+<p>You may nest any number of <a href="#core:descriptor">core:descriptor</a>
+elements within a <em>core:or</em> element. All of them will be evaluated
+in order to determine whether or not a branch to the Step specified by the
+<em>step</em> attribute should occur or not.</p>
+
+<p>In the following example, control will branch to the Step labelled
+<code>notOk</code> if any of the specified properties of the
+<code>address</code> bean return null String values. Otherwise,
+control will be transferred (via the <em>core:goto</em> Step)
+to the Step labelled <code>ok</code>.</p>
+<pre>
+ <core:and step="notOk">
+ <core:descriptor xpath="address/street1"/>
+ <core:descriptor xpath="address/city"/>
+ <core:descriptor xpath="address/state"/>
+ <core:descriptor xpath="address/zipCode"/>
+ </core:and>
+ <core:goto step="ok">
+</pre>
+
+
<a name="core:or"></a>
<h3>core:or</h3>
@@ -157,8 +255,45 @@
<h3>remove</h3>
<h3>string</h3>
+
+<a name="core:suspend"></a>
+<h3>core:suspend</h3>
-<h3>suspend</h3>
+<p>The <em>core:suspend</em> Step signals our
+<a href="../Context.html">Context</a> to suspend the execution of the Activity
+being processed. The most recent <code>Context.execute()</code> call will
+return immediately. On the next call to <code>Context.execute()</code>,
+processing will continue with the Step after this one.</p>
+
+<p>This Step is designed for scenarios where you wish to allow the application
+that is managing your workflows to interact with the user before proceeding.
+It is especially useful in a web environment, where Activity execution
+<strong>must</strong> be suspended in order to complete the current
+<code>HttpServletResponse</code>, and await the next
+<code>HttpServletRequest</code>.</p>
+
+<p><em>Note</em> - It does not matter how deeply nested you might be in
+<a href="#core:call">core:call</a> calls to subordinate Activity executions.
+The state of the entire computation is immediately suspended, and will resume
+on the next call to <code>Context.execute()</code>, without the calling
+application needing to be aware of the nesting.</p>
+
+<p>In the following example, it is assumed that you are using the Workflow
+system in an MVC-style framework, which uses
+<code>RequestDispatcher.forward()</code> to pass control to the resource
+responsible for creating a particular response. Control will be suspended
+until the next request comes in, at which point execution will be resumed.
+Thus, a simple multi-page interaction could be scripted like this (in a real
+scenario, you would want to deal with "next page" and "previous page"
+navigation links as well).</p>
+<pre>
+ <web:forward page="/page-1.jsp"/>
+ <core:suspend/>
+ ... process first input request ...
+ <web:forward page="/page=2.jsp"/>
+ <core:suspend/>
+ ... process second input request ...
+</pre>
<h3>swap</h3>
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