Plugin is now optional

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@15898 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/java/hudson/ClassicPluginStrategy.java

@@ -169,11 +169,6 @@ public class ClassicPluginStrategy implements PluginStrategy {
 	}
 
 	public void load(PluginWrapper wrapper) throws IOException {
-        String className = wrapper.getPluginClass();
-        if(className ==null) {
-            throw new IOException("Plugin installation failed. No 'Plugin-Class' entry in the manifest of "+wrapper.getShortName());
-        }
-
 		loadPluginDependencies(wrapper.getDependencies(),
 				wrapper.getOptionalDependencies());
 
@@ -185,6 +180,11 @@ public class ClassicPluginStrategy implements PluginStrategy {
         ClassLoader old = Thread.currentThread().getContextClassLoader();
         Thread.currentThread().setContextClassLoader(wrapper.classLoader);
         try {
+            String className = wrapper.getPluginClass();
+            if(className==null) {
+                // use the default dummy instance
+                wrapper.setPlugin(Plugin.NONE);
+            } else {
                 try {
                     Class clazz = wrapper.classLoader.loadClass(className);
                     Object o = clazz.newInstance();
@@ -199,6 +199,7 @@ public class ClassicPluginStrategy implements PluginStrategy {
                 } catch (InstantiationException e) {
                     throw new IOException2("Unable to create instance of " + className + " from " + wrapper.getShortName(),e);
                 }
+            }
 
             // initialize plugin
             try {

core/src/main/java/hudson/Plugin.java

@@ -229,4 +229,12 @@ public abstract class Plugin implements Saveable {
         return new XmlFile(Hudson.XSTREAM,
                 new File(Hudson.getInstance().getRootDir(),wrapper.getShortName()+".xml"));
     }
+
+    /**
+     * Dummy instance of {@link Plugin} to be used when a plugin didn't
+     * supply one on its own.
+     *
+     * @since 1.288
+     */
+    public static final Plugin NONE = new Plugin() {};
 }

core/src/main/java/hudson/PluginWrapper.java

@@ -31,7 +31,6 @@ import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.net.URL;
-import java.util.ArrayList;
 import java.util.List;
 import java.util.jar.Manifest;
 import java.util.logging.Logger;