mv com/google/domain/registry google/registry

This change renames directories in preparation for the great package
rename. The repository is now in a broken state because the code
itself hasn't been updated. However this should ensure that git
correctly preserves history for each file.

javatests/google/registry/server/UrlChecker.java

@@ -0,0 +1,70 @@
+// Copyright 2016 The Domain Registry 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 com.google.domain.registry.server;
+
+import com.google.common.base.Throwables;
+import com.google.common.util.concurrent.SimpleTimeLimiter;
+
+import java.io.IOException;
+import java.net.HttpURLConnection;
+import java.net.URL;
+import java.util.concurrent.Callable;
+import java.util.concurrent.TimeUnit;
+
+import javax.annotation.Nullable;
+
+final class UrlChecker {
+
+  private static final int READ_TIMEOUT_MS = 1000;
+  private static final int CONNECT_TIMEOUT_MS = 500;
+
+  /** Probes {@code url} until it becomes available. */
+  static void waitUntilAvailable(final URL url, int timeoutMs) {
+    try {
+      new SimpleTimeLimiter().callWithTimeout(new Callable<Void>() {
+        @Nullable
+        @Override
+        public Void call() throws InterruptedException, IOException {
+          int exponentialBackoffMs = 1;
+          while (true) {
+            if (isAvailable(url)) {
+              return null;
+            }
+            Thread.sleep(exponentialBackoffMs *= 2);
+          }
+        }
+      }, timeoutMs, TimeUnit.MILLISECONDS, true);
+    } catch (Exception e) {
+      throw Throwables.propagate(e);
+    }
+  }
+
+  /** Returns {@code true} if page is available and returns {@code 200 OK}. */
+  static boolean isAvailable(URL url) throws IOException {
+    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
+    connection.setConnectTimeout(CONNECT_TIMEOUT_MS);
+    connection.setReadTimeout(READ_TIMEOUT_MS);
+    try {
+      connection.connect();
+      return connection.getResponseCode() == HttpURLConnection.HTTP_OK;
+    } catch (IOException e) {
+      return false;
+    } finally {
+      connection.disconnect();
+    }
+  }
+
+  private UrlChecker() {}
+}