Merge pull request #12952 from rjernst/construct_it_yourself

Simplify Plugin API for constructing modules

core/src/main/java/org/elasticsearch/client/transport/TransportClient.java

@@ -260,7 +260,7 @@ public void close() {
             // ignore, might not be bounded
         }
 
-        for (Class<? extends LifecycleComponent> plugin : injector.getInstance(PluginsService.class).services()) {
+        for (Class<? extends LifecycleComponent> plugin : injector.getInstance(PluginsService.class).nodeServices()) {
             injector.getInstance(plugin).close();
         }
         try {

core/src/main/java/org/elasticsearch/node/Node.java

@@ -230,7 +230,7 @@ public Node start() {
         // hack around dependency injection problem (for now...)
         injector.getInstance(Discovery.class).setRoutingService(injector.getInstance(RoutingService.class));
 
-        for (Class<? extends LifecycleComponent> plugin : pluginsService.services()) {
+        for (Class<? extends LifecycleComponent> plugin : pluginsService.nodeServices()) {
             injector.getInstance(plugin).start();
         }
 
@@ -297,7 +297,7 @@ private Node stop() {
         injector.getInstance(RestController.class).stop();
         injector.getInstance(TransportService.class).stop();
 
-        for (Class<? extends LifecycleComponent> plugin : pluginsService.services()) {
+        for (Class<? extends LifecycleComponent> plugin : pluginsService.nodeServices()) {
             injector.getInstance(plugin).stop();
         }
         // we should stop this last since it waits for resources to get released
@@ -364,7 +364,7 @@ public synchronized void close() {
         stopWatch.stop().start("percolator_service");
         injector.getInstance(PercolatorService.class).close();
 
-        for (Class<? extends LifecycleComponent> plugin : pluginsService.services()) {
+        for (Class<? extends LifecycleComponent> plugin : pluginsService.nodeServices()) {
             stopWatch.stop().start("plugin(" + plugin.getName() + ")");
             injector.getInstance(plugin).close();
         }

core/src/main/java/org/elasticsearch/plugins/IndexPluginsModule.java

@@ -19,18 +19,12 @@
 
 package org.elasticsearch.plugins;
 
-import com.google.common.collect.Lists;
 import org.elasticsearch.common.inject.AbstractModule;
 import org.elasticsearch.common.inject.Module;
 import org.elasticsearch.common.inject.PreProcessModule;
 import org.elasticsearch.common.inject.SpawnModules;
 import org.elasticsearch.common.settings.Settings;
 
-import java.util.Collection;
-import java.util.List;
-
-import static org.elasticsearch.common.inject.Modules.createModule;
-
 /**
  *
  */
@@ -47,13 +41,7 @@ public IndexPluginsModule(Settings settings, PluginsService pluginsService) {
 
     @Override
     public Iterable<? extends Module> spawnModules() {
-        List<Module> modules = Lists.newArrayList();
-        Collection<Class<? extends Module>> modulesClasses = pluginsService.indexModules();
-        for (Class<? extends Module> moduleClass : modulesClasses) {
-            modules.add(createModule(moduleClass, settings));
-        }
-        modules.addAll(pluginsService.indexModules(settings));
-        return modules;
+        return pluginsService.indexModules(settings);
     }
 
     @Override

core/src/main/java/org/elasticsearch/plugins/Plugin.java

@@ -25,82 +25,73 @@
 
 import java.io.Closeable;
 import java.util.Collection;
+import java.util.Collections;
 
 /**
  * An extension point allowing to plug in custom functionality.
  * <p/>
- * A plugin can be dynamically injected with {@link Module} by implementing <tt>onModule(AnyModule)</tt> method
- * removing the need to override {@link #processModule(org.elasticsearch.common.inject.Module)} and check using
- * instanceof.
+ * A plugin can be register custom extensions to builtin behavior by implementing <tt>onModule(AnyModule)</tt>,
+ * and registering the extension with the given module.
  */
-public interface Plugin {
+public abstract class Plugin {
 
     /**
      * The name of the plugin.
      */
-    String name();
+    public abstract String name();
 
     /**
      * The description of the plugin.
      */
-    String description();
+    public abstract String description();
 
     /**
-     * Node level modules (classes, will automatically be created).
+     * Node level modules.
      */
-    Collection<Class<? extends Module>> modules();
-
-    /**
-     * Node level modules (instances)
-     *
-     * @param settings The node level settings.
-     */
-    Collection<? extends Module> modules(Settings settings);
+    public Collection<Module> nodeModules() {
+        return Collections.emptyList();
+    }
 
     /**
      * Node level services that will be automatically started/stopped/closed.
      */
-    Collection<Class<? extends LifecycleComponent>> services();
-
-    /**
-     * Per index modules.
-     */
-    Collection<Class<? extends Module>> indexModules();
+    public Collection<Class<? extends LifecycleComponent>> nodeServices() {
+        return Collections.emptyList();
+    }
 
     /**
      * Per index modules.
      */
-    Collection<? extends Module> indexModules(Settings settings);
+    public Collection<Module> indexModules(Settings indexSettings) {
+        return Collections.emptyList();
+    }
 
     /**
      * Per index services that will be automatically closed.
      */
-    Collection<Class<? extends Closeable>> indexServices();
+    public Collection<Class<? extends Closeable>> indexServices() {
+        return Collections.emptyList();
+    }
 
     /**
      * Per index shard module.
      */
-    Collection<Class<? extends Module>> shardModules();
-
-    /**
-     * Per index shard module.
-     */
-    Collection<? extends Module> shardModules(Settings settings);
+    public Collection<Module> shardModules(Settings indexSettings) {
+        return Collections.emptyList();
+    }
 
     /**
      * Per index shard service that will be automatically closed.
      */
-    Collection<Class<? extends Closeable>> shardServices();
-
-    /**
-     * Process a specific module. Note, its simpler to implement a custom <tt>onModule(AnyModule module)</tt>
-     * method, which will be automatically be called by the relevant type.
-     */
-    void processModule(Module module);
+    public Collection<Class<? extends Closeable>> shardServices() {
+        return Collections.emptyList();
+    }
 
     /**
      * Additional node settings loaded by the plugin. Note that settings that are explicit in the nodes settings can't be
      * overwritten with the additional settings. These settings added if they don't exist.
      */
-    Settings additionalSettings();
+    public Settings additionalSettings() {
+        return Settings.Builder.EMPTY_SETTINGS;
+    }
 }

core/src/main/java/org/elasticsearch/plugins/PluginsModule.java

@@ -19,18 +19,12 @@
 
 package org.elasticsearch.plugins;
 
-import com.google.common.collect.Lists;
 import org.elasticsearch.common.inject.AbstractModule;
 import org.elasticsearch.common.inject.Module;
 import org.elasticsearch.common.inject.PreProcessModule;
 import org.elasticsearch.common.inject.SpawnModules;
 import org.elasticsearch.common.settings.Settings;
 
-import java.util.Collection;
-import java.util.List;
-
-import static org.elasticsearch.common.inject.Modules.createModule;
-
 /**
  *
  */
@@ -47,13 +41,7 @@ public PluginsModule(Settings settings, PluginsService pluginsService) {
 
     @Override
     public Iterable<? extends Module> spawnModules() {
-        List<Module> modules = Lists.newArrayList();
-        Collection<Class<? extends Module>> modulesClasses = pluginsService.modules();
-        for (Class<? extends Module> moduleClass : modulesClasses) {
-            modules.add(createModule(moduleClass, settings));
-        }
-        modules.addAll(pluginsService.modules(settings));
-        return modules;
+        return pluginsService.nodeModules();
     }
 
     @Override