[jboss-svn-commits] JBL Code SVN: r15034 - labs/jbossrules/trunk/documentation/manual/en/Chapter-Examples.
jboss-svn-commits at lists.jboss.org
jboss-svn-commits at lists.jboss.org
Tue Sep 11 19:39:49 EDT 2007
Author: tirelli
Date: 2007-09-11 19:39:49 -0400 (Tue, 11 Sep 2007)
New Revision: 15034
Modified:
labs/jbossrules/trunk/documentation/manual/en/Chapter-Examples/Section-Examples.xml
Log:
Fixing docs
Modified: labs/jbossrules/trunk/documentation/manual/en/Chapter-Examples/Section-Examples.xml
===================================================================
--- labs/jbossrules/trunk/documentation/manual/en/Chapter-Examples/Section-Examples.xml 2007-09-11 23:26:47 UTC (rev 15033)
+++ labs/jbossrules/trunk/documentation/manual/en/Chapter-Examples/Section-Examples.xml 2007-09-11 23:39:49 UTC (rev 15034)
@@ -111,12 +111,123 @@
both dependent on B - causing a conflict which is resolved by setting
salience values.</para>
- <para></para>
+ <para>The best way to understand what is happening is to use the "Audit
+ Log" feature to graphically see the results of each operation. To do
+ that, follow the steps bellow:</para>
- <para>Before digging into the differences between the examples, it is
- important to note some common concepts to all examples.</para>
+ <orderedlist>
+ <listitem>
+ <para>Open the class org.drools.examples.StateExampleUsingSalience
+ in your Eclipse IDE</para>
+ </listitem>
- <para>The first important concept is the use of <emphasis
+ <listitem>
+ <para>Right-click the class an select "Run as..." -> "Java
+ application"</para>
+ </listitem>
+
+ <listitem>
+ <para>If the "Audit View" is not visible, click on:
+ "Window"->"Show View"->"Other..."->"Drools"->"Audit
+ View"</para>
+ </listitem>
+
+ <listitem>
+ <para>In the "Audit View" click in the "Open Log" button and select
+ the file "<drools-examples-drl-dir>/log/state.log"</para>
+ </listitem>
+ </orderedlist>
+
+ <para>After that, the "Audit view" will look like the following
+ screenshot.</para>
+
+ <para><screenshot>
+ <screeninfo>State Example Audit View</screeninfo>
+
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="state_example_audit1.png" />
+ </imageobject>
+ </mediaobject>
+ </screenshot></para>
+
+ <para>Reading the log in the "Audit View", top to down, we see every
+ action and the corresponding changes in the working memory. This way we
+ see that the assertion of the State "A" object with the "NOTRUN" state
+ activates the "Bootstrap" rule, while the assertions of the other state
+ objects have no immediate effect.</para>
+
+ <example>
+ <title>State Example: Rule "Bootstrap"</title>
+
+ <programlisting>rule Bootstrap
+ when
+ a : State(name == "A", state == State.NOTRUN )
+ then
+ System.out.println(a.getName() + " finished" );
+ a.setState( State.FINISHED );
+end</programlisting>
+ </example>
+
+ <para>The execution of "Bootstrap" rule changes the state of "A" to
+ "FINISHED", that in turn activates the "A to B" rule.</para>
+
+ <example>
+ <title>State Example: Rule "A to B"</title>
+
+ <programlisting>rule "A to B"
+ when
+ State(name == "A", state == State.FINISHED )
+ b : State(name == "B", state == State.NOTRUN )
+ then
+ System.out.println(b.getName() + " finished" );
+ b.setState( State.FINISHED );
+end
+</programlisting>
+ </example>
+
+ <para>The execution of "A to B" rule changes the state of "B" to
+ "FINISHED", what activates both rules "B to C" and "B to D". In this
+ moment, two rules may fire and the conflict resolution strategy is what
+ allows the engine to decide which rule to fire first. As the "B to C"
+ rule has a <emphasis role="bold">higher salience value</emphasis> (10
+ versus the default salience value of 0), it fires first, modifying the
+ "C" object to state "FINISHED".</para>
+
+ <example>
+ <title>State Example: Rule "B to C"</title>
+
+ <programlisting>rule "B to C"
+ salience 10
+ when
+ State(name == "B", state == State.FINISHED )
+ c : State(name == "C", state == State.NOTRUN )
+ then
+ System.out.println(c.getName() + " finished" );
+ c.setState( State.FINISHED );
+end
+</programlisting>
+ </example>
+
+ <para>The "B to D" rule fires last, modifying the "D" object to state
+ "FINISHED".</para>
+
+ <example>
+ <title>State Example: Rule "B to D"</title>
+
+ <programlisting>rule "B to D"
+ when
+ State(name == "B", state == State.FINISHED )
+ d : State(name == "D", state == State.NOTRUN )
+ then
+ System.out.println(d.getName() + " finished" );
+ d.setState( State.FINISHED );
+end</programlisting>
+ </example>
+
+ <para>There are no more rules to execute and so the engine stops.</para>
+
+ <para>Another notable concept in this example is the use of <emphasis
role="bold">dynamic facts</emphasis>. As mentioned previously in the
documentation, in order for the engine to see and react to fact's
properties change, the application must tell the engine that changes
@@ -138,21 +249,7 @@
session.insert( fact,
dynamic );
</programlisting>
-
- <para></para>
-
- <para></para>
</section>
-
- <section>
- <title>State Example using Salience</title>
-
- <para></para>
-
- <para></para>
-
- <para></para>
- </section>
</section>
<section>
@@ -647,295 +744,4 @@
</itemizedlist>
</section>
</section>
-
- <section>
- <title>Hello World</title>
-
- <programlisting><emphasis role="bold">Name:</emphasis> Hello World
-<emphasis role="bold">Main class:</emphasis> org.drools.examples.HelloWorldExample
-<emphasis role="bold">Type:</emphasis> java application
-<emphasis role="bold">Rules file:</emphasis> HelloWorld.drl
-<emphasis role="bold">Objective:</emphasis> demonstrate basic rules in use
-</programlisting>
-
- <para>The "Hello World" example shows a simple example of rules usage.
- Lets take a quick look at the rules.</para>
-
- <example>
- <title>HelloWorld example: rule "Hello World"</title>
-
- <programlisting>rule "Hello World"
- dialect "mvel"
- when
- m : Message( status == Message.HELLO, message : message )
- then
- System.out.println( message );
- m.message = "Goodbyte cruel world";
- m.status = 1;
- update ( m );
-end
-</programlisting>
- </example>
-
- <para>The <emphasis role="bold">LHS (when)</emphasis> section of the rule
- states that it will be activated for each <emphasis>Message</emphasis>
- object inserted into the working memory whose <emphasis>status</emphasis>
- is <emphasis>Message.HELLO</emphasis>. Besides that, two variable binds
- are created: "<emphasis>message</emphasis>" variable is bound to the
- <emphasis>message</emphasis> attribute and "<emphasis>m</emphasis>"
- variable is bound to the <emphasis>pattern</emphasis> itself.</para>
-
- <para>The <emphasis role="bold">RHS (consequence, then)</emphasis> section
- of the rule is written using the MVEL expression language, as declared by
- the rule's attribute <emphasis>dialect</emphasis>. After printing the
- content of the <emphasis>message</emphasis> bound variable to the default
- console, the rule changes the values of the <emphasis>message</emphasis>
- and <emphasis>status</emphasis> attributes of the <emphasis>m</emphasis>
- bound variable. Finally, in order for the engine to "see" the new values
- of the attributes, a call to the <emphasis role="bold">update()</emphasis>
- memory action is made on the <emphasis>m</emphasis> fact.</para>
-
- <example>
- <title>HelloWorld example: rule "Good Bye"</title>
-
- <programlisting>rule "Good Bye"
- dialect "mvel"
- when
- Message( status == Message.GOODBYE, message : message )
- then
- System.out.println( message );
-end</programlisting>
- </example>
-
- <para>The "Good Bye" rule is similar to the "Hello World" but matches
- Message objects whose status is Message.GOODBYE instead, printing its
- message to the default console.</para>
- </section>
-
- <section>
- <title>State Example</title>
-
- <para>This example is actually implemented in three different versions to
- demonstrate different ways of implementing the same basic behavior: rules
- forward chaining, i.e., the ability the engine has to evaluate, activate
- and fire rules in sequence, based on changes on the facts in the working
- memory.</para>
-
- <section>
- <title>Understanding the State Example</title>
-
- <para><programlisting><emphasis role="bold">Name:</emphasis> State Example
-<emphasis role="bold">Main class:</emphasis> org.drools.examples.StateExampleUsingSalience
-<emphasis role="bold">Type:</emphasis> java application
-<emphasis role="bold">Rules file:</emphasis> StateExampleUsingSalience.drl
-</programlisting>Each State class has fields for its name and its current
- state (see org.drools.examples.State class). The two possible states for
- each objects are:</para>
-
- <itemizedlist>
- <listitem>
- <para>NOTRUN</para>
- </listitem>
-
- <listitem>
- <para>FINISHED</para>
- </listitem>
- </itemizedlist>
-
- <para>In the example we have four objects: A, B, C and D. Initially all
- are set to state NOTRUN. A Bootstrap rule fires setting A to state
- FINISHED which then causes B to change to state FINISHED. C and D are
- both dependent on B - causing a conflict which is resolved by setting
- salience values.</para>
-
- <para>The best way to understand what is happening is to use the "Audit
- Log" feature to graphically see the results of each operation. To do
- that, follow the steps bellow:</para>
-
- <orderedlist>
- <listitem>
- <para>Open the class org.drools.examples.StateExampleUsingSalience
- in your Eclipse IDE</para>
- </listitem>
-
- <listitem>
- <para>Right-click the class an select "Run as..." -> "Java
- application"</para>
- </listitem>
-
- <listitem>
- <para>If the "Audit View" is not visible, click on:
- "Window"->"Show View"->"Other..."->"Drools"->"Audit
- View"</para>
- </listitem>
-
- <listitem>
- <para>In the "Audit View" click in the "Open Log" button and select
- the file "<drools-examples-drl-dir>/log/state.log"</para>
- </listitem>
- </orderedlist>
-
- <para>After that, the "Audit view" will look like the following
- screenshot.</para>
-
- <para><screenshot>
- <screeninfo>State Example Audit View</screeninfo>
-
- <mediaobject>
- <imageobject>
- <imagedata fileref="state_example_audit1.png" />
- </imageobject>
- </mediaobject>
- </screenshot></para>
-
- <para>Reading the log in the "Audit View", top to down, we see every
- action and the corresponding changes in the working memory. This way we
- see that the assertion of the State "A" object with the "NOTRUN" state
- activates the "Bootstrap" rule, while the assertions of the other state
- objects have no immediate effect. </para>
-
- <example>
- <title>State Example: Rule "Bootstrap"</title>
-
- <programlisting>rule Bootstrap
- when
- a : State(name == "A", state == State.NOTRUN )
- then
- System.out.println(a.getName() + " finished" );
- a.setState( State.FINISHED );
-end</programlisting>
- </example>
-
- <para>The execution of "Bootstrap" rule changes the state of "A" to
- "FINISHED", that in turn activates the "A to B" rule.</para>
-
- <example>
- <title>State Example: Rule "A to B"</title>
-
- <programlisting>rule "A to B"
- when
- State(name == "A", state == State.FINISHED )
- b : State(name == "B", state == State.NOTRUN )
- then
- System.out.println(b.getName() + " finished" );
- b.setState( State.FINISHED );
-end
-</programlisting>
- </example>
-
- <para>The execution of "A to B" rule changes the state of "B" to
- "FINISHED", what activates both rules "B to C" and "B to D". In this
- moment, two rules may fire and the conflict resolution strategy is what
- allows the engine to decide which rule to fire first. As the "B to C"
- rule has a <emphasis role="bold">higher salience value</emphasis> (10
- versus the default salience value of 0), it fires first, modifying the
- "C" object to state "FINISHED".</para>
-
- <example>
- <title>State Example: Rule "B to C"</title>
-
- <programlisting>rule "B to C"
- salience 10
- when
- State(name == "B", state == State.FINISHED )
- c : State(name == "C", state == State.NOTRUN )
- then
- System.out.println(c.getName() + " finished" );
- c.setState( State.FINISHED );
-end
-</programlisting>
- </example>
-
- <para>The "B to D" rule fires last, modifying the "D" object to state
- "FINISHED". </para>
-
- <example>
- <title>State Example: Rule "B to D"</title>
-
- <programlisting>rule "B to D"
- when
- State(name == "B", state == State.FINISHED )
- d : State(name == "D", state == State.NOTRUN )
- then
- System.out.println(d.getName() + " finished" );
- d.setState( State.FINISHED );
-end</programlisting>
- </example>
-
- <para>There are no more rules to execute and so the engine stops.</para>
-
- <para>Another notable concept in this example is the use of <emphasis
- role="bold">dynamic facts</emphasis>. As mentioned previously in the
- documentation, in order for the engine to see and react to fact's
- properties change, the application must tell the engine that changes
- occurred. This can be done explicitly in the rules, by calling the
- <emphasis role="bold">update()</emphasis> memory action as seen in the
- "Hello World" example, or implicitly by letting the engine know that the
- facts implement PropertyChangeSupport as defined by the
- <emphasis>Javabeans specification</emphasis>. This example demonstrates
- how to use PropertyChangeSupport to avoid the need for explicit update()
- calls in the rules. To make use of this feature, make sure your facts
- implement the PropertyChangeSupport as the org.drools.example.State
- class does and use the following code to insert the facts into the
- working memory:</para>
-
- <programlisting> // By setting dynamic to TRUE, Drools will use JavaBean
- // PropertyChangeListeners so you don't have to call update().
- final boolean dynamic = true;
-
- session.insert( fact,
- dynamic );
-</programlisting>
- </section>
-
- <section>
- <para />
-
- <para />
-
- <para />
- </section>
- </section>
-
- <section>
- <title>Fibonacci Example</title>
-
- <para></para>
- </section>
-
- <section>
- <title>Golfing Example</title>
-
- <para></para>
- </section>
-
- <section>
- <title>Trouble Ticket</title>
-
- <para></para>
- </section>
-
- <section>
- <title>Pricing Rule DT Example</title>
-
- <para></para>
- </section>
-
- <section>
- <title>Shopping Example</title>
-
- <para></para>
- </section>
-
- <section>
- <title>Honest Politician Example</title>
-
- <para></para>
- </section>
-
- <section>
- <title>Conways Game of Life</title>
-
- <para></para>
- </section>
-</section>
+</section>
\ No newline at end of file
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