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From craig...@apache.org
Subject cvs commit: jakarta-commons-sandbox/workflow/src/java/org/apache/commons/workflow/core package.html
Date Sun, 18 Nov 2001 23:38:51 GMT
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
  ===================================================================
  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>
  +  &lt;base:activity id="Demonstration Activity"
  +    xmlns:base="http://jakarta.apache.org/commons/workflow/base"
  +    xmlns:core="http://jakarta.apache.org/commons/workflow/core"
  +  &gt;
  +
  +    &lt;core:string value="This is a string value"/&gt;
  +
  +  &lt;/base:activity&gt;
  +</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>&lt;core:descriptor&gt;</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>&lt;core:descriptor&gt; 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>
  +  &lt;core:and step="ok"&gt;
  +    &lt;core:descriptor xpath="address/street1"/&gt;
  +    &lt;core:descriptor xpath="address/city"/&gt;
  +    &lt;core:descriptor xpath="address/state"/&gt;
  +    &lt;core:descriptor xpath="address/zipCode"/&gt;
  +  &lt;/core:and&gt;
  +  &lt;core:goto step="notOk"&gt;
  +</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>&lt;core:descriptor&gt;</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>&lt;core:descriptor&gt; 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>
  +  &lt;core:or step="selected"&gt;
  +    &lt;core:descriptor xpath="options/red"/&gt;
  +    &lt;core:descriptor xpath="options/blue"/&gt;
  +    &lt;core:descriptor xpath="options/green"/&gt;
  +    &lt;core:descriptor xpath="options/white"/&gt;
  +  &lt;/core:or&gt;
  +  &lt;core:goto step="notSelected"&gt;
  +</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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