Import code from internal repository to git

java/com/google/domain/registry/request/JsonActionRunner.java

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+// Copyright 2016 Google Inc. 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.request;
+
+import static com.google.common.base.Verify.verifyNotNull;
+
+import java.util.Map;
+
+import javax.inject.Inject;
+
+/** Runner for actions that read and write JSON objects. */
+public final class JsonActionRunner {
+
+  /** Interface for actions that read and write JSON objects. */
+  public interface JsonAction {
+
+    /**
+     * Handles JSON HTTP request.
+     *
+     * @param json object extracted from request body
+     * @return an arbitrary JSON object, which is never {@code null}
+     * @throws HttpException to send a non-200 status code / message to client
+     */
+    Map<String, ?> handleJsonRequest(Map<String, ?> json);
+  }
+
+  @Inject @JsonPayload Map<String, Object> payload;
+  @Inject JsonResponse response;
+  @Inject JsonActionRunner() {}
+
+  /** Delegates request to {@code action}. */
+  public void run(JsonAction action) {
+    response.setPayload(
+        verifyNotNull(
+            action.handleJsonRequest(payload),
+            "handleJsonRequest() returned null"));
+  }
+}