Clarify example in usage about updatePomFile behavior

Author: slawekjaranowski

README.md

@@ -10,27 +10,7 @@ This is the [flatten-maven-plugin](http://www.mojohaus.org/flatten-maven-plugin/
 
 This plugin generates a flattened version of your pom.xml and makes maven to install and deploy this one instead of the original pom.xml.
 
-```
-<build>
-  <plugins>
-    <plugin>
-      <groupId>org.codehaus.mojo</groupId>
-      <artifactId>flatten-maven-plugin</artifactId>
-      <!--<version>INSERT LATEST VERSION HERE</version>-->
-      <executions>
-        <execution>
-          <goals>
-            <goal>flatten</goal>
-          </goals>
-        </execution>
-      </executions>
-      <configuration>
-        <!-- See usage on maven site from link above for details -->
-      </configuration>
-    </plugin>
-  </plugins>
-</build>
-```
+Please refer to the [Usage page](https://www.mojohaus.org/flatten-maven-plugin/usage.html) for simple example.
 
 ## Releasing
 

src/main/java/org/codehaus/mojo/flatten/FlattenMojo.java

@@ -1310,7 +1310,12 @@ public boolean isUpdatePomFile() {
             if (this.flattenMode == FlattenMode.bom) {
                 return true;
             }
-            return !this.project.getPackaging().equals("pom");
+            if (this.project.getPackaging().equals("pom")) {
+                getLog().info("Project POM file not updated to point to the flattened POM due to 'pom' packaging");
+                return false;
+            } else {
+                return true;
+            }
         } else {
             return this.updatePomFile;
         }

src/site/xdoc/usage.xml.vm

@@ -39,6 +39,16 @@
     </plugins>
   </build>
       ]]></source>
+
+      <subsection name="NOTICE">
+        <p>The generated flattened POM will be set as POM file to the current project only for projects with packaging other than <code>pom</code>.
+        You may want to also do this for <code>pom</code> packaging projects by setting the parameter <code>updatePomFile</code> to <code>true</code>.</p>
+
+        <p>If <code>flattenMode</code> is set to <code>bom</code> the generated flattened POM will be set as a project POM file also for <code>pom</code> packaging.</p>
+
+        <p>Setting generated flattened POM as a project POM file will allow to install/deploy the generated POM instead of actual project POM file.</p>
+      </subsection>
+
       <subsection name="Keep developer information">
         If you want to keep additional development information in your POM you can configure predefined modes via the <code>flattenMode</code> parameter.
         For typical open-source-projects you can choose "oss". To keep all additional POM elements and flatten only to a bare minimum use "resolveCiFriendliesOnly".