Get rid of the GerritServer static singleton

Instead we obtain it through Guice only, letting the Injector manage
providing it as required.

Signed-off-by: Shawn O. Pearce <sop@google.com>

src/main/java/com/google/gerrit/server/GerritServer.java

@@ -39,7 +39,7 @@ import com.google.gwtorm.client.OrmException;
 import com.google.gwtorm.client.SchemaFactory;
 import com.google.gwtorm.client.Transaction;
 import com.google.gwtorm.jdbc.Database;
-import com.google.gwtorm.jdbc.SimpleDataSource;
+import com.google.inject.Inject;
 import com.google.inject.Singleton;
 
 import net.sf.ehcache.Cache;
@@ -68,46 +68,22 @@ import org.spearce.jgit.lib.WindowCacheConfig;
 import org.spearce.jgit.lib.RepositoryCache.FileKey;
 
 import java.io.File;
-import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.IOException;
-import java.io.InputStream;
-import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
-import java.util.Map;
-import java.util.Properties;
 
-import javax.naming.InitialContext;
-import javax.naming.NamingException;
 import javax.servlet.http.HttpServletRequest;
-import javax.sql.DataSource;
 
 /** Global server-side state for Gerrit. */
 @Singleton
 public class GerritServer {
   private static final Logger log = LoggerFactory.getLogger(GerritServer.class);
-  private static DataSource datasource;
-  private static GerritServer impl;
   private static CacheManager cacheMgr;
 
-  static void closeDataSource() {
-    if (datasource != null) {
-      try {
-        try {
-          Class.forName("com.mchange.v2.c3p0.DataSources").getMethod("destroy",
-              DataSource.class).invoke(null, datasource);
-        } catch (Throwable bad) {
-          // Oh well, its not a c3p0 pooled connection. Too bad its
-          // not standardized how "good applications cleanup".
-        }
-      } finally {
-        datasource = null;
-      }
-    }
-
+  static void closeCacheManager() {
     if (cacheMgr != null) {
       try {
         cacheMgr.shutdown();
@@ -118,35 +94,6 @@ public class GerritServer {
     }
   }
 
-  /**
-   * Obtain the singleton server instance for this web application.
-   * 
-   * @return the server instance. Never null.
-   * @throws OrmException the database could not be configured. There is
-   *         something wrong with the schema configuration in {@link ReviewDb}
-   *         that must be addressed by a developer.
-   * @throws XsrfException the XSRF support could not be correctly configured to
-   *         protect the application against cross-site request forgery. The JVM
-   *         is most likely lacking critical security algorithms.
-   */
-  public static synchronized GerritServer getInstance() throws OrmException,
-      XsrfException {
-    if (impl == null) {
-      try {
-        impl = new GerritServer();
-      } catch (OrmException e) {
-        closeDataSource();
-        log.error("GerritServer ORM is unavailable", e);
-        throw e;
-      } catch (XsrfException e) {
-        closeDataSource();
-        log.error("GerritServer XSRF support failed to initailize", e);
-        throw e;
-      }
-    }
-    return impl;
-  }
-
   public static String serverUrl(final HttpServletRequest req) {
     // Assume this servlet is in the context with a simple name like "login"
     // and we were accessed without any path info. Clipping the last part of
@@ -177,8 +124,10 @@ public class GerritServer {
   private final SelfPopulatingCache diffCache;
   private final SelfPopulatingCache sshKeysCache;
 
-  private GerritServer() throws OrmException, XsrfException {
-    db = createDatabase();
+  @Inject
+  GerritServer(final Database<ReviewDb> database)
+      throws OrmException, XsrfException {
+    db = database;
     loadSystemConfig();
     if (sConfig == null) {
       throw new OrmException("No " + SystemConfig.class.getName() + " found");
@@ -353,54 +302,6 @@ public class GerritServer {
     return r;
   }
 
-  public static Database<ReviewDb> createDatabase() throws OrmException {
-    final String dsName = "java:comp/env/jdbc/ReviewDb";
-    try {
-      datasource = (DataSource) new InitialContext().lookup(dsName);
-    } catch (NamingException namingErr) {
-      final Properties p = readGerritDataSource();
-      if (p == null) {
-        throw new OrmException("Initialization error:\n" + "  * No DataSource "
-            + dsName + "\n" + "  * No -DGerritServer=GerritServer.properties"
-            + " on Java command line", namingErr);
-      }
-
-      try {
-        datasource = new SimpleDataSource(p);
-      } catch (SQLException se) {
-        throw new OrmException("Database unavailable", se);
-      }
-    }
-    return new Database<ReviewDb>(datasource, ReviewDb.class);
-  }
-
-  private static Properties readGerritDataSource() throws OrmException {
-    final Properties srvprop = new Properties();
-    String name = System.getProperty("GerritServer");
-    if (name == null) {
-      name = "GerritServer.properties";
-    }
-    try {
-      final InputStream in = new FileInputStream(name);
-      try {
-        srvprop.load(in);
-      } finally {
-        in.close();
-      }
-    } catch (IOException e) {
-      throw new OrmException("Cannot read " + name, e);
-    }
-
-    final Properties dbprop = new Properties();
-    for (final Map.Entry<Object, Object> e : srvprop.entrySet()) {
-      final String key = (String) e.getKey();
-      if (key.startsWith("database.")) {
-        dbprop.put(key.substring("database.".length()), e.getValue());
-      }
-    }
-    return dbprop;
-  }
-
   private void initSystemConfig(final ReviewDb c) throws OrmException {
     final AccountGroup admin =
         new AccountGroup(new AccountGroup.NameKey("Administrators"),

src/main/java/com/google/gerrit/server/GerritServerModule.java

@@ -14,28 +14,34 @@
 
 package com.google.gerrit.server;
 
+import static com.google.inject.Scopes.SINGLETON;
+
 import com.google.gerrit.client.data.GerritConfig;
+import com.google.gerrit.client.reviewdb.ReviewDb;
 import com.google.gerrit.git.ChangeMergeQueue;
 import com.google.gerrit.git.MergeQueue;
 import com.google.gerrit.git.PushReplication;
 import com.google.gerrit.git.ReplicationQueue;
-import com.google.gwtjsonrpc.server.XsrfException;
-import com.google.gwtorm.client.OrmException;
+import com.google.gwtorm.jdbc.Database;
 import com.google.inject.AbstractModule;
-import static com.google.inject.Scopes.SINGLETON;
+import com.google.inject.Key;
+import com.google.inject.TypeLiteral;
+import com.google.inject.name.Names;
+
+import javax.sql.DataSource;
 
 /** Starts {@link GerritServer} with standard dependencies. */
 public class GerritServerModule extends AbstractModule {
+  public static final Key<DataSource> DS =
+      Key.get(DataSource.class, Names.named("ReviewDb"));
+
   @Override
   protected void configure() {
-    try {
-      bind(GerritServer.class).toInstance(GerritServer.getInstance());
-    } catch (OrmException e) {
-      addError(e);
-    } catch (XsrfException e) {
-      addError(e);
-    }
+    bind(DS).toProvider(ReviewDbDataSourceProvider.class).in(SINGLETON);
+    bind(new TypeLiteral<Database<ReviewDb>>() {}).toProvider(
+        ReviewDbProvider.class).in(SINGLETON);
 
+    bind(GerritServer.class);
     bind(ContactStore.class).toProvider(EncryptedContactStoreProvider.class);
     bind(FileTypeRegistry.class).to(MimeUtilFileTypeRegistry.class);
     bind(ReplicationQueue.class).to(PushReplication.class).in(SINGLETON);

src/main/java/com/google/gerrit/server/GerritServletConfig.java

@@ -50,6 +50,7 @@ import java.util.HashSet;
 import java.util.concurrent.TimeUnit;
 
 import javax.servlet.ServletContextEvent;
+import javax.sql.DataSource;
 
 /** Configures the web application environment for Gerrit Code Review. */
 public class GerritServletConfig extends GuiceServletContextListener {
@@ -227,15 +228,26 @@ public class GerritServletConfig extends GuiceServletContextListener {
       // Assume it never started.
     }
 
+    WorkQueue.terminate();
+    GerritServer.closeCacheManager();
+
     try {
-      final GerritServer gs = injector.getInstance(GerritServer.class);
-      gs.closeDataSource();
+      final DataSource ds = injector.getInstance(GerritServerModule.DS);
+      try {
+        final Class<?> type = Class.forName("com.mchange.v2.c3p0.DataSources");
+        if (type.isInstance(ds)) {
+          type.getMethod("destroy", DataSource.class).invoke(null, ds);
+        }
+      } catch (Throwable bad) {
+        // Oh well, its not a c3p0 pooled connection. Too bad its
+        // not standardized how "good applications cleanup".
+      }
     } catch (ConfigurationException ce) {
       // Assume it never started.
     } catch (ProviderException ce) {
       // Assume it never started.
     }
-    WorkQueue.terminate();
+
     super.contextDestroyed(event);
   }
 }

src/main/java/com/google/gerrit/server/ReviewDbDataSourceProvider.java

@@ -0,0 +1,82 @@
+// Copyright (C) 2009 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server;
+
+import com.google.gwtorm.jdbc.SimpleDataSource;
+import com.google.inject.Provider;
+import com.google.inject.ProvisionException;
+
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.sql.SQLException;
+import java.util.Map;
+import java.util.Properties;
+
+import javax.naming.InitialContext;
+import javax.naming.NamingException;
+import javax.sql.DataSource;
+
+/** Provides access to the {@code ReviewDb} DataSource. */
+final class ReviewDbDataSourceProvider implements Provider<DataSource> {
+  @Override
+  public DataSource get() {
+    final String dsName = "java:comp/env/jdbc/ReviewDb";
+    try {
+      return (DataSource) new InitialContext().lookup(dsName);
+    } catch (NamingException namingErr) {
+      final Properties p = readGerritDataSource();
+      if (p == null) {
+        throw new ProvisionException("Initialization error:\n"
+            + "  * No DataSource " + dsName + "\n"
+            + "  * No -DGerritServer=GerritServer.properties"
+            + " on Java command line", namingErr);
+      }
+
+      try {
+        return new SimpleDataSource(p);
+      } catch (SQLException se) {
+        throw new ProvisionException("Database unavailable", se);
+      }
+    }
+  }
+
+  private static Properties readGerritDataSource() throws ProvisionException {
+    final Properties srvprop = new Properties();
+    String name = System.getProperty("GerritServer");
+    if (name == null) {
+      name = "GerritServer.properties";
+    }
+    try {
+      final InputStream in = new FileInputStream(name);
+      try {
+        srvprop.load(in);
+      } finally {
+        in.close();
+      }
+    } catch (IOException e) {
+      throw new ProvisionException("Cannot read " + name, e);
+    }
+
+    final Properties dbprop = new Properties();
+    for (final Map.Entry<Object, Object> e : srvprop.entrySet()) {
+      final String key = (String) e.getKey();
+      if (key.startsWith("database.")) {
+        dbprop.put(key.substring("database.".length()), e.getValue());
+      }
+    }
+    return dbprop;
+  }
+}

src/main/java/com/google/gerrit/server/ReviewDbProvider.java

@@ -0,0 +1,44 @@
+// Copyright (C) 2009 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server;
+
+import com.google.gerrit.client.reviewdb.ReviewDb;
+import com.google.gwtorm.client.OrmException;
+import com.google.gwtorm.jdbc.Database;
+import com.google.inject.Inject;
+import com.google.inject.Provider;
+import com.google.inject.ProvisionException;
+import com.google.inject.name.Named;
+
+import javax.sql.DataSource;
+
+/** Provides the {@link ReviewDb} database handle. */
+final class ReviewDbProvider implements Provider<Database<ReviewDb>> {
+  private final DataSource datasource;
+
+  @Inject
+  ReviewDbProvider(@Named("ReviewDb") final DataSource ds) {
+    datasource = ds;
+  }
+
+  @Override
+  public Database<ReviewDb> get() {
+    try {
+      return new Database<ReviewDb>(datasource, ReviewDb.class);
+    } catch (OrmException e) {
+      throw new ProvisionException("Cannot create ReviewDb", e);
+    }
+  }
+}