HBASE-3581 hbase rpc should send size of response

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1185618 13f79535-47bb-0310-9956-ffa450edef68

src/main/java/org/apache/hadoop/hbase/ipc/ResponseFlag.java

@@ -0,0 +1,47 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.hadoop.hbase.ipc;
+
+/**
+ * Utility for managing the flag byte passed in response to a
+ * {@link HBaseServer.Call}
+ */
+class ResponseFlag {
+  private static final byte ERROR_BIT = 0x1;
+  private static final byte LENGTH_BIT = 0x2;
+
+  private ResponseFlag() {
+    // Make it so this class cannot be constructed.
+  }
+
+  static boolean isError(final byte flag) {
+    return (flag & ERROR_BIT) != 0;
+  }
+
+  static boolean isLength(final byte flag) {
+    return (flag & LENGTH_BIT) != 0;
+  }
+
+  static byte getLengthSetOnly() {
+    return LENGTH_BIT;
+  }
+
+  static byte getErrorAndLengthSet() {
+    return LENGTH_BIT & ERROR_BIT;
+  }
+}