Command to resave datastore entities by websafe key

While I am doing this, promote LoadAndResaveEntityCommand from
javascrap to the main tool since it's repeatedly been useful, and
rename it and update its documentation to better reflect the
difference between that command and the one I am adding.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=139460841

java/google/registry/tools/ResaveEppResourceCommand.java

@@ -0,0 +1,81 @@
+// Copyright 2016 The Nomulus Authors. All Rights Reserved.
+//
+// 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 google.registry.tools;
+
+import static google.registry.model.index.ForeignKeyIndex.loadAndGetKey;
+import static google.registry.model.ofy.ObjectifyService.ofy;
+import static google.registry.util.PreconditionsUtils.checkArgumentNotNull;
+import static org.joda.time.DateTimeZone.UTC;
+
+import com.beust.jcommander.Parameter;
+import com.beust.jcommander.Parameters;
+import com.googlecode.objectify.Key;
+import google.registry.model.EppResource;
+import google.registry.model.contact.ContactResource;
+import google.registry.model.domain.DomainApplication;
+import google.registry.model.domain.DomainResource;
+import google.registry.model.host.HostResource;
+import org.joda.time.DateTime;
+
+/**
+ * A command to load and resave an {@link EppResource} by foreign key.
+ *
+ * <p>This triggers @OnSave changes. If the entity was directly edited in the datastore viewer, this
+ * can be used to make sure that the commit logs reflect the new state.
+ */
+@Parameters(
+    separators = " =",
+    commandDescription = "Load and resave EPP resources by foreign key")
+public final class ResaveEppResourceCommand extends MutatingCommand {
+
+  private enum ResourceType { CONTACT, HOST, DOMAIN, APPLICATION }
+
+  @Parameter(
+    names = "--type",
+    description = "Resource type.")
+  protected ResourceType type;
+
+  @Parameter(
+    names = "--id",
+    description = "Foreign key of the resource, or application ID of the domain application.")
+  protected String uniqueId;
+
+  @Override
+  protected void init() throws Exception {
+    Key<? extends EppResource> resourceKey = checkArgumentNotNull(
+        getResourceKey(type, uniqueId, DateTime.now(UTC)),
+        "Could not find active resource of type %s: %s", type, uniqueId);
+    // Load the resource directly to bypass running cloneProjectedAtTime() automatically, which can
+    // cause stageEntityChange() to fail due to implicit projection changes.
+    EppResource resource = ofy().load().key(resourceKey).now();
+    stageEntityChange(resource, resource);
+  }
+
+  private Key<? extends EppResource> getResourceKey(
+      ResourceType type, String uniqueId, DateTime now) {
+    switch (type) {
+      case CONTACT:
+        return loadAndGetKey(ContactResource.class, uniqueId, now);
+      case HOST:
+        return loadAndGetKey(HostResource.class, uniqueId, now);
+      case DOMAIN:
+        return loadAndGetKey(DomainResource.class, uniqueId, now);
+      case APPLICATION:
+        return Key.create(DomainApplication.class, uniqueId);
+      default:
+        throw new IllegalStateException("Unknown type: " + type);
+    }
+  }
+}