add optional module support and jmx example

jetty-start/src/main/java/org/eclipse/jetty/start/Module.java

@@ -60,6 +60,8 @@ public class Module extends TextFile
     private String name;
     /** List of Modules, by name, that this Module depends on */
     private Set<String> parentNames;
+    /** List of Modules, by name, that this Module optionally depend on */
+    private Set<String> optionalParentNames;
     /** The Edges to parent modules */
     private Set<Module> parentEdges;
     /** The Edges to child modules */
@@ -143,6 +145,11 @@ public class Module extends TextFile
         return name;
     }
 
+    public Set<String> getOptionalParentNames()
+    {
+        return optionalParentNames;
+    }
+    
     public Set<Module> getParentEdges()
     {
         return parentEdges;
@@ -176,6 +183,7 @@ public class Module extends TextFile
         this.name = Pattern.compile(".mod$",Pattern.CASE_INSENSITIVE).matcher(name).replaceFirst("");
 
         this.parentNames = new HashSet<>();
+        this.optionalParentNames = new HashSet<>();
         this.parentEdges = new HashSet<>();
         this.childEdges = new HashSet<>();
         this.xmls = new ArrayList<>();
@@ -206,6 +214,10 @@ public class Module extends TextFile
 
             switch (key.toUpperCase(Locale.ENGLISH))
             {
+                case "OPTIONAL":
+                    optionalParentNames.add(value);
+                    handled = true;
+                    break;
                 case "DEPEND":
                     parentNames.add(value);
                     handled = true;

jetty-start/src/main/java/org/eclipse/jetty/start/Modules.java

@@ -84,13 +84,13 @@ public class Modules implements Iterable<Module>
     }
 
     /**
-     * Using the provided dependenies, build the module graph
+     * Using the provided dependencies, build the module graph
      */
     public void buildGraph()
     {
         // Connect edges
         for (Module module : modules.values())
-        {
+        {   
             for (String parentName : module.getParentNames())
             {
                 Module parent = get(parentName);
@@ -100,6 +100,17 @@ public class Modules implements Iterable<Module>
                     parent.addChildEdge(module);
                 }
             }
+            
+            for (String optionalParentName : module.getOptionalParentNames())
+            {
+                Module optional = get(optionalParentName);
+                
+                if (optional != null && optional.isEnabled())
+                {
+                    module.addParentEdge(optional);
+                    optional.addChildEdge(module);
+                }
+            }
         }
 
         // Verify there is no cyclic references

jetty-start/src/test/java/org/eclipse/jetty/start/TestUseCases.java

@@ -50,4 +50,10 @@ public class TestUseCases
     {
         assertUseCase("home","base.barebones","assert-barebones.txt");
     }
+    
+    @Test
+    public void testJMX() throws Exception
+    {
+        assertUseCase("home","base.jmx","assert-jmx.txt");
+    }
 }

jetty-start/src/test/resources/usecases/assert-jmx.txt

@@ -0,0 +1,18 @@
+# The XMLs we expect (order is important)
+XML|${jetty.home}/etc/jetty-jmx.xml
+XML|${jetty.home}/etc/jetty.xml
+XML|${jetty.home}/etc/jetty-http.xml
+
+# The LIBs we expect (order is irrelevant)
+LIB|${jetty.home}/lib/jetty-continuation-TEST.jar
+LIB|${jetty.home}/lib/jetty-http-TEST.jar
+LIB|${jetty.home}/lib/jetty-io-TEST.jar
+LIB|${jetty.home}/lib/jetty-jmx-TEST.jar
+LIB|${jetty.home}/lib/jetty-schemas-3.1.jar
+LIB|${jetty.home}/lib/jetty-server-TEST.jar
+LIB|${jetty.home}/lib/jetty-util-TEST.jar
+LIB|${jetty.home}/lib/jetty-xml-TEST.jar
+LIB|${jetty.home}/lib/servlet-api-3.1.jar
+
+# The Properties we expect (order is irrelevant)
+PROP|jetty.port=9090

jetty-start/src/test/resources/usecases/base.jmx/start.ini

@@ -0,0 +1,4 @@
+
+MODULES=server,http,jmx
+
+jetty.port=9090

jetty-start/src/test/resources/usecases/home/modules/base.mod

@@ -2,5 +2,7 @@
 # Base Module
 #
 
+OPTIONAL=jmx
+
 LIB=lib/jetty-util-${jetty.version}.jar
 LIB=lib/jetty-io-${jetty.version}.jar