craigmcc 01/11/18 22:40:17
Modified: workflow/src/java/org/apache/commons/workflow/core
LoadStep.java package.html
Log:
That's enough documentation for one night ...
Revision Changes Path
1.3 +19 -9
jakarta-commons-sandbox/workflow/src/java/org/apache/commons/workflow/core/LoadStep.java
Index: LoadStep.java
===================================================================
RCS file:
/home/cvs/jakarta-commons-sandbox/workflow/src/java/org/apache/commons/workflow/core/LoadStep.java,v
retrieving revision 1.2
retrieving revision 1.3
diff -u -r1.2 -r1.3
--- LoadStep.java 2001/09/20 02:13:55 1.2
+++ LoadStep.java 2001/11/19 06:40:17 1.3
@@ -1,7 +1,7 @@
/*
- * $Header:
/home/cvs/jakarta-commons-sandbox/workflow/src/java/org/apache/commons/workflow/core/LoadStep.java,v
1.2 2001/09/20 02:13:55 craigmcc Exp $
- * $Revision: 1.2 $
- * $Date: 2001/09/20 02:13:55 $
+ * $Header:
/home/cvs/jakarta-commons-sandbox/workflow/src/java/org/apache/commons/workflow/core/LoadStep.java,v
1.3 2001/11/19 06:40:17 craigmcc Exp $
+ * $Revision: 1.3 $
+ * $Date: 2001/11/19 06:40:17 $
*
* ====================================================================
*
@@ -75,13 +75,15 @@
* <p>Supported Attributes:</p>
* <ul>
* <li><strong>name</strong> - The fully qualified name of the Java class
- * to be loaded.</li>
+ * to be loaded. If not specified, the top of the evaluation stack
+ * is popped, converted to a String (if necessary), and used as the
+ * name of the class to be loaded.</li>
* <li><strong>thread</strong> - Should the class be loaded from the current
* Thread's context class loader? (Default is to load from the same
* class loader that loaded this class).</li>
* </ul>
*
- * @version $Revision: 1.2 $ $Date: 2001/09/20 02:13:55 $
+ * @version $Revision: 1.3 $ $Date: 2001/11/19 06:40:17 $
* @author Craig R. McClanahan
*/
@@ -200,10 +202,15 @@
throw new StepException
("No thread context class loader is available");
+ // Calculate the name of the class to be loaded
+ String className = getName();
+ if (className == null)
+ className = context.pop().toString();
+
// Load the specified class
Class clazz = null;
try {
- clazz = classLoader.loadClass(name);
+ clazz = classLoader.loadClass(className);
} catch (Throwable t) {
throw new StepException
("Exception from loadClass()", t, this);
@@ -225,10 +232,13 @@
sb.append(" id=\"");
sb.append(getId());
sb.append("\"");
+ }
+ if (getName() != null) {
+ sb.append(" name=\"");
+ sb.append(getName());
+ sb.append("\"");
}
- sb.append(" name=\"");
- sb.append(getName());
- sb.append("\" thread=\"");
+ sb.append(" thread=\"");
sb.append(getThread());
sb.append("\"/>");
return (sb.toString());
1.4 +204 -26
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 1.3
retrieving revision 1.4
diff -u -r1.3 -r1.4
--- package.html 2001/11/19 04:56:49 1.3
+++ package.html 2001/11/19 06:40:17 1.4
@@ -28,6 +28,13 @@
</base:activity>
</pre>
+<p><em>NOTE</em> - It is <strong>not</strong> required that you use the XML
+syntax, processed with a Digester, to initialize the Steps associated with
+each Activity. However, this usage is very convenient, and is likely to be
+the most common case, so the Steps are documented from that perspective. To
+use the underlying implementation classes directly, see the Javadocs for each
+Step implementation class, just as you would for any other Java class.</p>
+
<div align="center">
[<a href="#core:and">core:and</a>]
[<a href="#core:call">core:call</a>]
@@ -81,13 +88,13 @@
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">
+ <strong><core:and step="ok"></strong>
<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">
+ <strong></core:and></strong>
+ <core:goto step="notOk"/>
</pre>
<a name="core:call"></a>
@@ -100,6 +107,13 @@
Activity executes an <a href="#core:exit">core:exit</a> Step, or the last
defined Step in the Activity has been executed.</p>
+<p>The <em>core:call</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>
+</ul>
+
<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
@@ -108,23 +122,147 @@
<core:get>
<core:descriptor xpath="process/activity"/>
</core:get>
- <core:call>
+ <strong><core:call/></strong>
+</pre>
+
+
+<a name="core:construct"></a>
+<h3>core:construct</h3>
+
+<p>The <em>core:construct</em> Step creates a new object of the specified
+class, and pushes it onto the stack. The specified class, and the optional
+argument(s) to the constructor, are defined by the nested
+<a href="core:descriptor">core:descriptor</a> elements.</p>
+
+<p>The <em>core:construct</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>
+</ul>
+
+<p>At least one nested <em>core:descriptor</em> element is required, although
+more than one are allowed. They are interpreted as follows:</p>
+<ul>
+<li>The <strong>first</strong> descriptor must identify an object of type
+ <code>java.lang.Class</code>, representing the Class of the object to be
+ created. For script readability, you can use <code>core:class</code> as an
+ alias for <code>core:descriptor</code> in the first nested descriptor,
+ but it is interpreted identically.</li>
+<li>Any subsequent descriptors represent arguments to the constructor, in the
+ order they are defined on the constructor itself. The
+ workflow engine will attempt to find a matching constructor on the
+ specified class (throwing an exception if none can be found), and will
+ then use that constructor to instantiate a new instance.
+</ul>
+
+<p><strong>FIXME</strong> - Currently, this Step does not correctly recognize
+constructors that accept primitive argument types.</p>
+
+<p>In the example below, it is assumed that the top item on the evaluation
+stack is an instance of <code>java.lang.Class</code>, produced by some
+unspecified previous processing. This class has a constructor that takes
+two arguments - a <code>java.util.Map</code> and a
+<code>java.lang.String</code> - that are returned by appropriate bean
+properties.</p>
+<pre>
+ <strong><core:construct></strong>
+ <core:class/> <-- Top item is a Class -->
+ <core:descriptor xpath="foo/map" type="java.util.Map"/>
+ <core:descriptor xpath="bar/string"/>
+ <strong></core:construct></strong>
+</pre>
+
+
+<a name="core:duplicate"></a>
+<h3>core:duplicate</h3>
+
+<p>The <em>core:duplicate</em> Step peeks at the top value on the evaluation
+stack and pushes another copy of it onto the stack. This is useful in
+scenarios where you execute Steps that consume items from the stack, but you
+wish to maintain a reference to the top object.</p>
+
+<p>The <em>core:duplicate</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>
+</ul>
+
+<p>In the example below, the script wants to display the top item on the
+stack (for debugging purposes) without consuming it.</p>
+<pre>
+ <strong><core:duplicate/></strong>
+ <io:display>
+ <io:descriptor/> <-- Consumes top stack item -->
+ </io:display>
</pre>
+<a name="core:exit"></a>
+<h3>core:exit</h3>
+
+<p>The <em>core:exit</em> Step causes execution of the current Activity to be
+completed, just as if the last Step in the Activity had been executed. If this
+Activity was executed as the result of a <a href="#core:call">core:call</a>
+invocation, control will resume with the next Step in the calling Activity.
+Otherwise, the <code>Context.execute()</code> call from the application will
+return control to the calling application.</p>
+
+<p>The <em>core:exit</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>
+</ul>
+
+
+<a name="core:get"></a>
+<h3>core:get</h3>
+
-<h3>construct</h3>
+<a name="core:goto"></a>
+<h3>core:goto</h3>
-<h3>duplicate</h3>
-<h3>exit</h3>
+<a name="core:invoke"></a>
+<h3>core:invoke</h3>
-<h3>get</h3>
-<h3>goto</h3>
+<a name="core:load"></a>
+<h3>core:load</h3>
+
+<p>The <em>core:load</em> Step causes the specified
+<code>java.lang.Class</code> to be loaded, and the corresponding
+<code>Class</code> object pushed onto the top of the execution stack.
+The name of the class to be loaded can be specified either statically
+or dynamically.</p>
+
+<p>The <em>core:load</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>name</strong> - Fully qualified name of the Java class to be
+ loaded. If not specified, the top of the evaluation stack will be
+ popped, converted to a String (if necessary), and used as the name of
+ the Class to be loaded.</li>
+<li><strong>thread</strong> - Boolean attribute that determines whether the
+ class should be loaded from the current Thread's context class loader
+ if set to <code>true</code>. By default, the class is loaded from the
+ same class loader that loaded the <code>LoadStep</code> implementation
+ class.</li>
+</ul>
-<h3>invoke</h3>
+<p>In the example below, the <code>java.util.Date</code> class is loaded, and
+a new <code>Date</code> instance is constructed using the zero-arguments
+constructor and pushed on to the evaluation stack.</p>
+<pre>
+ <strong><core:load name="java.util.Date"/></strong>
+ <core:construct>
+ <core:descriptor/> <-- Consumes top item from the stack -->
+ </core:construct>
+</pre>
-<h3>load</h3>
<a name="notAnd"></a>
<h3>core:notAnd</h3>
@@ -158,15 +296,16 @@
be transferred (via the <em>core:goto</em> Step) to the Step labelled
<code>notEmpty</code>.</p>
<pre>
- <core:notAnd step="empty">
+ <strong><core:notAnd step="empty"></strong>
<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">
+ <strong></core:notAnd></strong>
+ <core:goto step="notEmpty"/>
</pre>
+
<a name="core:notOr"></a>
<h3>core:notOr</h3>
@@ -199,13 +338,13 @@
control will be transferred (via the <em>core:goto</em> Step)
to the Step labelled <code>ok</code>.</p>
<pre>
- <core:and step="notOk">
+ <strong><core:notOr step="notOk"></strong>
<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">
+ <strong></core:notOr></strong>
+ <core:goto step="ok"/>
</pre>
@@ -239,23 +378,42 @@
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">
+ <strong><core:or step="selected"></strong>
<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">
+ <strong><core:goto step="notSelected"/></strong>
</pre>
+
+<a name="core:pop"></a>
+<h3>core:pop</h3>
+
+
+<a name="core:put"></a>
+<h3>core:put</h3>
+
+
+<a name="core:remove"></a>
+<h3>core:remove</h3>
-<h3>pop</h3>
-<h3>put</h3>
+<a name="core:string"></a>
+<h3>core:string</h3>
-<h3>remove</h3>
+<p>The <em>core:string</em> Step pushes the specified literal String value
+onto the top of the evaluation stack.</p>
-<h3>string</h3>
+<p>The <em>core:string</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>value</strong> - The literal String value to be pushed.</li>
+</ul>
+
<a name="core:suspend"></a>
<h3>core:suspend</h3>
@@ -278,6 +436,13 @@
on the next call to <code>Context.execute()</code>, without the calling
application needing to be aware of the nesting.</p>
+<p>The <em>core:suspend</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>
+</ul>
+
<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
@@ -288,14 +453,27 @@
navigation links as well).</p>
<pre>
<web:forward page="/page-1.jsp"/>
- <core:suspend/>
+ <strong><core:suspend/></strong>
... process first input request ...
<web:forward page="/page=2.jsp"/>
- <core:suspend/>
+ <strong><core:suspend/></strong>
... process second input request ...
</pre>
+
+
+<a name="core:swap"></a>
+<h3>core:swap</h3>
+
+<p>The <em>core:swap</em> Step swaps the top two items on the evaluation
+stack. This can be useful when previous processing has generated items on the
+stack that are not in the desired order for future processing.</p>
-<h3>swap</h3>
+<p>The <em>core:swap</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>
+</ul>
<div align="center">
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