Rewrite our build as modular maven components

This refactoring splits the code up into different components, with
their own per-component CLASSPATH.  By moving all of our classes
into isolated components we can better isolate the classpaths and
try to avoid unexpected dependency problems.  It also allows us to
more clearly define which components are used by the GWT UI and
thus must be compiled under GWT, and which components are run on
the server and can therefore use more of the J2SE API.

Change-Id: I833cc22bacc5655d1c9099ed7c2b0e0a5b08855a
Signed-off-by: Shawn O. Pearce <sop@google.com>

gerrit-gwtui/src/main/java/com/google/gerrit/client/rpc/GerritCallback.java

@@ -0,0 +1,83 @@
+// Copyright (C) 2008 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.client.rpc;
+
+import com.google.gerrit.client.ErrorDialog;
+import com.google.gerrit.client.Gerrit;
+import com.google.gerrit.client.NotSignedInDialog;
+import com.google.gerrit.common.errors.NameAlreadyUsedException;
+import com.google.gerrit.common.errors.NoSuchAccountException;
+import com.google.gerrit.common.errors.NoSuchEntityException;
+import com.google.gerrit.common.errors.NotSignedInException;
+import com.google.gwt.core.client.GWT;
+import com.google.gwt.user.client.rpc.AsyncCallback;
+import com.google.gwt.user.client.rpc.InvocationException;
+import com.google.gwtjsonrpc.client.JsonUtil;
+import com.google.gwtjsonrpc.client.RemoteJsonException;
+import com.google.gwtjsonrpc.client.ServerUnavailableException;
+
+/** Abstract callback handling generic error conditions automatically */
+public abstract class GerritCallback<T> implements AsyncCallback<T> {
+  public void onFailure(final Throwable caught) {
+    if (isNotSignedIn(caught) || isInvalidXSRF(caught)) {
+      new NotSignedInDialog().center();
+
+    } else if (isNoSuchEntity(caught)) {
+      new ErrorDialog(Gerrit.C.notFoundBody()).center();
+
+    } else if (isNoSuchAccount(caught)) {
+      final String msg = caught.getMessage();
+      final String who = msg.substring(NoSuchAccountException.MESSAGE.length());
+      final ErrorDialog d = new ErrorDialog(Gerrit.M.noSuchAccountMessage(who));
+      d.setText(Gerrit.C.noSuchAccountTitle());
+      d.center();
+
+    } else if (isNameAlreadyUsed(caught)) {
+      new ErrorDialog(Gerrit.C.nameAlreadyUsedBody()).center();
+
+    } else if (caught instanceof ServerUnavailableException) {
+      new ErrorDialog(RpcConstants.C.errorServerUnavailable()).center();
+
+    } else {
+      GWT.log(getClass().getName() + " caught " + caught, caught);
+      new ErrorDialog(caught).center();
+    }
+  }
+
+  private static boolean isInvalidXSRF(final Throwable caught) {
+    return caught instanceof InvocationException
+        && caught.getMessage().equals(JsonUtil.ERROR_INVALID_XSRF);
+  }
+
+  private static boolean isNotSignedIn(final Throwable caught) {
+    return caught instanceof RemoteJsonException
+        && caught.getMessage().equals(NotSignedInException.MESSAGE);
+  }
+
+  protected static boolean isNoSuchEntity(final Throwable caught) {
+    return caught instanceof RemoteJsonException
+        && caught.getMessage().equals(NoSuchEntityException.MESSAGE);
+  }
+
+  private static boolean isNoSuchAccount(final Throwable caught) {
+    return caught instanceof RemoteJsonException
+        && caught.getMessage().startsWith(NoSuchAccountException.MESSAGE);
+  }
+
+  private static boolean isNameAlreadyUsed(final Throwable caught) {
+    return caught instanceof RemoteJsonException
+        && caught.getMessage().equals(NameAlreadyUsedException.MESSAGE);
+  }
+}