craigmcc 01/11/18 15:38:51
Modified: workflow/src/java/org/apache/commons/workflow/core
package.html
Log:
Begin the process of documenting the library of available Steps, assuming
the use of the XML rule sets for Digester.
Revision Changes Path
1.2 +191 -10
jakarta-commons-sandbox/workflow/src/java/org/apache/commons/workflow/core/package.html
Index: package.html
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RCS file:
/home/cvs/jakarta-commons-sandbox/workflow/src/java/org/apache/commons/workflow/core/package.html,v
retrieving revision 1.1
retrieving revision 1.2
diff -u -r1.1 -r1.2
--- package.html 2001/08/13 21:18:26 1.1
+++ package.html 2001/11/18 23:38:51 1.2
@@ -1,16 +1,197 @@
<body>
-<p>Implementations of <code>Steps</code> in the <code>core</code>
-namespace.</p>
+<p>Implementations of <code>Steps</code> in the <em>core</em> library.</p>
-<p>This package contains the following sets of classes:</p>
+<div align="center">
+<h2>Core Step Library - Overview</h2>
+</div>
+
+<p>This package contains
+<a href="../Step.html">org.apache.commons.workflow.Step</a> implementations
+for the <em>core</em> library. This library includes Steps for fundamental
+object stack manipulation, as well as conditional branching. Such Steps are
+commonly required in defining Activities, no matter what domain you are using
+the Workflow system in.</p>
+
+<p>The sections below define each of the Step definitions included in this
+library, utilizing the XML syntax that is recognized by the Digester used to
+process your Activity definition files. Although you can use any namespace
+prefix, the convention is to declare <code>core</code> as the namespace prefix,
+as in the following example:</p>
+<pre>
+ <base:activity id="Demonstration Activity"
+ xmlns:base="http://jakarta.apache.org/commons/workflow/base";
+ xmlns:core="http://jakarta.apache.org/commons/workflow/core";
+ >
+
+ <core:string value="This is a string value"/>
+
+ </base:activity>
+</pre>
+
+<div align="center">
+[<a href="#core:and">core:and</a>]
+[<a href="#core:call">core:call</a>]
+[<a href="#core:construct">core:construct</a>]
+[<a href="#core:duplicate">core:duplicate</a>]
+[<a href="#core:exit">core:exit</a>]
+[<a href="#core:get">core:get</a>]
+[<a href="#core:goto">core:goto</a>]
+[<a href="#core:invoke">core:invoke</a>]
+[<a href="#core:load">core:load</a>]
+[<a href="#core:notAnd">core:notAnd</a>]
+[<a href="#core:notOr">core:notOr</a>]
+[<a href="#core:or">core:or</a>]
+[<a href="#core:pop">core:pop</a>]
+[<a href="#core:put">core:put</a>]
+[<a href="#core:remove">core:remove</a>]
+[<a href="#core:string">core:string</a>]
+[<a href="#core:suspend">core:suspend</a>]
+[<a href="#core:swap">core:swap</a>]
+</div>
+
+<div align="center">
+<h2>Core Step Library - Step Definitions</h2>
+</div>
+
+<a name="core:and"></a>
+<h3>core:and</h3>
+
+<p>The <em>core:and</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>true</code> (if boolean) or not null
+(if Object). To avoid non-deterministic evaluation stack behavior, all of
+the nested <code><core:descriptor> elements are always evaluated.</p>
+
+<p>The <em>core:and</em> element recognizes the following attributes:
<ul>
-<li><strong>XxxxxStep</strong> - Implementations of <code>Step</code>
- for fundamental tasks related to the evaluation stack, as well
- as beans stored into (and retrieved from) various <code>Scopes</code>.
- These <code>Steps</code> rely only on the standard APIs of
- JDK 1.2 (or later) or JRE 1.2 (or later).</li>
+<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:and</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>ok</code> if all of the specified properties of the <code>address</code>
+bean return non-null String values. Otherwise, control will be transferred
+(via the <em>core:goto</em> Step) to the Step labelled <code>notOk</code>.</p>
+<pre>
+ <core:and step="ok">
+ <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="notOk">
+</pre>
+
+<h3>core:call</h3>
+
+<h3>construct</h3>
+
+<h3>duplicate</h3>
+
+<h3>exit</h3>
+
+<h3>get</h3>
+
+<h3>goto</h3>
+
+<h3>invoke</h3>
+
+<h3>load</h3>
+
+<h3>notAnd</h3>
+
+<h3>notOr</h3>
+
+
+<a name="core:or"></a>
+<h3>core:or</h3>
+
+<p>The <em>core:or</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>true</code> (if boolean) or not null
+(if Object). To avoid non-deterministic evaluation stack behavior, all of
+the nested <code><core:descriptor> elements are always evaluated.</p>
+
+<p>The <em>core:or</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>selected</code> if at least one of the specified properties of the
+<code>options</code> object (presumably recording a set of boolean options,
+perhaps initialized from a series of checkboxes on an HTML form) is selected.
+Otherwise, control will be transferred (via the <em>core:goto</em> Step) to
+the Step labelled <code>notSelected</code>.</p>
+<pre>
+ <core:or step="selected">
+ <core:descriptor xpath="options/red"/>
+ <core:descriptor xpath="options/blue"/>
+ <core:descriptor xpath="options/green"/>
+ <core:descriptor xpath="options/white"/>
+ </core:or>
+ <core:goto step="notSelected">
+</pre>
+
+<h3>pop</h3>
+
+<h3>put</h3>
+
+<h3>remove</h3>
+
+<h3>string</h3>
+
+<h3>suspend</h3>
+
+<h3>swap</h3>
+
+
+<div align="center">
+<h2>Core Step Library - Nested Elements</h2>
+</div>
+
+<a name="core:descriptor"></a>
+<h3>core:descriptor</h3>
+
+<p>A <em>descriptor</em> is a description of the mechanism by which an
+arbitrary Java object (typically a JavaBean) in some Scope is referenced.
+The following reference methods are supported, and are processed in the
+order specified here:</p>
+<ul>
+<li>If the <em>xpath</em> attribute is set, it is used as an
+ XPath expression identifying the requested object.</li>
+<li>If the <em>name</em> (and optional <em>scope</em>) attributes are
+ specified, they are used to select a particular named bean,
+ optionally found in a particular named scope.</li>
+<li>If none of the conditions above are satisfied, the top object on the
+ evaluation stack of our current <code>Context</code> is popped off the
+ stack and consumed.</li>
+</ul>
+
+<p>Besides the attributes listed above, you can also specify an optional
+<em>type</em> attribute containing the fully qualified class name of the
+Java class that the referenced object is expected to be assignment-compatible
+with (i.e. this is either a class name of the class itself, a class name of a
+superclass, or an interface implemented by this object's class). This value
+is used only by particular Step implementations, as defined in the
+descriptions for those Steps.</p>
+
-<p>By convention, the <code>Steps</code> in this package are exposed as part
-of the <code>core</code> namespace in configuration files.</p>
</body>
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