group descriptors configuration by category

close #31

demos/git/README.md

@@ -5,10 +5,11 @@
 ## sample configuration
 
 ```yaml
-git:
-  installations:
-    - name: git
-      home: /usr/local/bin/git
+tool:
+  git:
+    installations:
+      - name: git
+        home: /usr/local/bin/git
 ```
 
 ## implementation note

src/main/java/org/jenkinsci/plugins/casc/Configurator.java

@@ -4,6 +4,7 @@ import hudson.Extension;
 import hudson.ExtensionList;
 import hudson.ExtensionPoint;
 import hudson.model.Describable;
+import hudson.model.Descriptor;
 import hudson.model.TopLevelItem;
 import hudson.remoting.Which;
 import jenkins.model.Jenkins;
@@ -49,7 +50,8 @@ public abstract class Configurator<T> implements ExtensionPoint {
 
         Class clazz = asClass(type);
 
-        final ExtensionList<Configurator> l = Jenkins.getInstance().getExtensionList(Configurator.class);
+        final Jenkins jenkins = Jenkins.getInstance();
+        final ExtensionList<Configurator> l = jenkins.getExtensionList(Configurator.class);
         for (Configurator c : l) {
             if (clazz == c.getTarget()) {
                 // this type has a dedicated Configurator implementation
@@ -69,6 +71,10 @@ public abstract class Configurator<T> implements ExtensionPoint {
             return lookup(actualType);
         }
 
+        if (Descriptor.class.isAssignableFrom(clazz)) {
+            return new DescriptorRootElementConfigurator((Descriptor) jenkins.getExtensionList(clazz).get(0));
+        }
+
         if (getDataBoundConstructor(clazz) != null) {
             return new DataBoundConfigurator(clazz);
         }

src/main/java/org/jenkinsci/plugins/casc/GlobalConfigurationCategoryConfigurator.java

@@ -0,0 +1,69 @@
+package org.jenkinsci.plugins.casc;
+
+import hudson.ExtensionList;
+import hudson.model.Descriptor;
+import jenkins.model.GlobalConfigurationCategory;
+import jenkins.model.Jenkins;
+import org.apache.commons.lang.StringUtils;
+import org.jenkinsci.Symbol;
+
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * @author <a href="mailto:nicolas.deloof@gmail.com">Nicolas De Loof</a>
+ */
+public class GlobalConfigurationCategoryConfigurator extends BaseConfigurator implements RootElementConfigurator {
+
+    private final GlobalConfigurationCategory category;
+
+    public GlobalConfigurationCategoryConfigurator(GlobalConfigurationCategory category) {
+        this.category = category;
+    }
+
+    @Override
+    public String getName() {
+        final Class c = category.getClass();
+        final Symbol symbol = (Symbol) c.getAnnotation(Symbol.class);
+        if (symbol != null) return symbol.value()[0];
+
+        String name = c.getSimpleName();
+        name = StringUtils.remove(name, "Global");
+        name = StringUtils.remove(name, "Configuration");
+        name = StringUtils.remove(name, "Category");
+        return name;
+    }
+
+    @Override
+    public Class getTarget() {
+        return category.getClass();
+    }
+
+    @Override
+    public Object configure(Object config) throws Exception {
+        configure((Map) config, category);
+        return category;
+    }
+
+    @Override
+    public Set<Attribute> describe() {
+
+        Set<Attribute> attributes = new HashSet<>();
+        final ExtensionList<Descriptor> descriptors = Jenkins.getInstance().getExtensionList(Descriptor.class);
+        for (Descriptor descriptor : descriptors) {
+            if (descriptor.getCategory() == category && descriptor.getGlobalConfigPage() != null) {
+
+                final DescriptorRootElementConfigurator configurator = new DescriptorRootElementConfigurator(descriptor);
+                attributes.add(new Attribute(configurator.getName(), configurator.getTarget()) {
+                    @Override
+                    public void setValue(Object target, Object value) throws Exception {
+                        // No actual attribute to set, DescriptorRootElementConfigurator manages singleton Descriptor components
+                    }
+                });
+            }
+        }
+        return attributes;
+    }
+
+}

src/main/java/org/jenkinsci/plugins/casc/RootElementConfigurator.java

@@ -2,6 +2,7 @@ package org.jenkinsci.plugins.casc;
 
 import hudson.ExtensionList;
 import hudson.model.Descriptor;
+import jenkins.model.GlobalConfigurationCategory;
 import jenkins.model.Jenkins;
 
 import java.util.ArrayList;
@@ -20,10 +21,14 @@ public interface RootElementConfigurator {
         final Jenkins jenkins = Jenkins.getInstance();
         configurators.addAll(jenkins.getExtensionList(RootElementConfigurator.class));
 
-        // Check for Descriptors with a global.jelly view
+        for (GlobalConfigurationCategory category : GlobalConfigurationCategory.all()) {
+            configurators.add(new GlobalConfigurationCategoryConfigurator(category));
+        }
+
+        // Check for unclassified Descriptors
         final ExtensionList<Descriptor> descriptors = jenkins.getExtensionList(Descriptor.class);
         for (Descriptor descriptor : descriptors) {
-            if (descriptor.getGlobalConfigPage() != null) {
+            if (descriptor.getGlobalConfigPage() != null && descriptor.getCategory() instanceof GlobalConfigurationCategory.Unclassified) {
                 configurators.add(new DescriptorRootElementConfigurator(descriptor));
             }
         }

src/test/resources/org/jenkinsci/plugins/casc/GitToolInstallationTest.yml

@@ -1,8 +1,8 @@
-
-git:
-  installations:
-    - name: git
-      home: /bin/git
-    - name: another_git
-      home: /usr/local/bin/git
+tool:
+  git:
+    installations:
+      - name: git
+        home: /bin/git
+      - name: another_git
+        home: /usr/local/bin/git