Merge pull request #141 from aozarov/temp1

Enable running against gcloud datastore emulator (using DATASTORE_HOST)

Author: ludoch

gcloud-java-core/src/main/java/com/google/gcloud/ServiceOptions.java

@@ -154,7 +154,7 @@ public B serviceRpcFactory(ServiceRpcFactory<ServiceRpcT, OptionsT> serviceRpcFa
 
   protected ServiceOptions(Builder<ServiceRpcT, OptionsT, ?> builder) {
     projectId = checkNotNull(builder.projectId != null ? builder.projectId : defaultProject());
-    host = firstNonNull(builder.host, DEFAULT_HOST);
+    host = firstNonNull(builder.host, defaultHost());
     httpTransportFactory =
         firstNonNull(builder.httpTransportFactory, DefaultHttpTransportFactory.INSTANCE);
     authCredentials = firstNonNull(builder.authCredentials, defaultAuthCredentials());
@@ -191,6 +191,10 @@ protected static String appEngineAppId() {
     return System.getProperty("com.google.appengine.application.id");
   }
 
+  protected String defaultHost() {
+    return DEFAULT_HOST;
+  }
+
   protected String defaultProject() {
     String projectId = System.getProperty(PROJECT_ENV_NAME, System.getenv(PROJECT_ENV_NAME));
     if (projectId == null) {

gcloud-java-datastore/src/main/java/com/google/gcloud/datastore/DatastoreOptions.java

@@ -38,6 +38,7 @@ public class DatastoreOptions extends ServiceOptions<DatastoreRpc, DatastoreOpti
 
   private static final long serialVersionUID = -8636602944160689193L;
   private static final String DATASET_ENV_NAME = "DATASTORE_DATASET";
+  private static final String HOST_ENV_NAME = "DATASTORE_HOST";
   private static final String DATASTORE_SCOPE = "https://www.googleapis.com/auth/datastore";
   private static final String USERINFO_SCOPE = "https://www.googleapis.com/auth/userinfo.email";
   private static final Set<String> SCOPES = ImmutableSet.of(DATASTORE_SCOPE, USERINFO_SCOPE);
@@ -122,6 +123,12 @@ private DatastoreOptions normalize() {
     }
   }
 
+  @Override
+  protected String defaultHost() {
+    String host = System.getProperty(HOST_ENV_NAME, System.getenv(HOST_ENV_NAME));
+    return host != null ? host : super.defaultHost();
+  }
+
   @Override
   protected String defaultProject() {
     String projectId = System.getProperty(DATASET_ENV_NAME, System.getenv(DATASET_ENV_NAME));