liblttng-ust-java-agent/java/lttng-ust-agent-common/org/lttng/ust/agent/client/LttngAgentResponse.java

   1 /*
   2  * Copyright (C) 2015 - EfficiOS Inc., Alexandre Montplaisir <alexmonthy@efficios.com>
   3  * Copyright (C) 2013 - David Goulet <dgoulet@efficios.com>
   4  *
   5  * This library is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU Lesser General Public License, version 2.1 only,
   7  * as published by the Free Software Foundation.
   8  *
   9  * This library is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
  12  * for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public License
  15  * along with this library; if not, write to the Free Software Foundation,
  16  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  17  */
  18
  19 package org.lttng.ust.agent.client;
  20
  21 import java.nio.ByteBuffer;
  22 import java.nio.ByteOrder;
  23
  24 /**
  25  * Interface for all response messages sent from the Java agent to the sessiond
  26  * daemon. Normally sent after a command coming from the session daemon was
  27  * executed.
  28  *
  29  * @author Alexandre Montplaisir
  30  */
  31 abstract class LttngAgentResponse {
  32
  33         private static final int INT_SIZE = 4;
  34
  35         /**
  36          * Return codes used in agent responses, to indicate success or different
  37          * types of failures of the commands.
  38          */
  39         protected enum ReturnCode {
  40
  41                 CODE_SUCCESS_CMD(1),
  42                 CODE_INVALID_CMD(2),
  43                 CODE_UNKNOWN_LOGGER_NAME(3);
  44
  45                 private int code;
  46
  47                 private ReturnCode(int c) {
  48                         code = c;
  49                 }
  50
  51                 public int getCode() {
  52                         return code;
  53                 }
  54         }
  55
  56         /**
  57          * Get the {@link ReturnCode} that goes with this response. It is expected
  58          * by the session daemon, but some commands may require more than this
  59          * in their response.
  60          *
  61          * @return The return code
  62          */
  63         public abstract ReturnCode getReturnCode();
  64
  65         /**
  66          * Gets a byte array of the response so that it may be streamed.
  67          *
  68          * @return The byte array of the response
  69          */
  70         public byte[] getBytes() {
  71                 byte data[] = new byte[INT_SIZE];
  72                 ByteBuffer buf = ByteBuffer.wrap(data);
  73                 buf.order(ByteOrder.BIG_ENDIAN);
  74                 buf.putInt(getReturnCode().getCode());
  75                 return data;
  76         }
  77
  78         public static final LttngAgentResponse SUCESS_RESPONSE = new LttngAgentResponse() {
  79                 @Override
  80                 public ReturnCode getReturnCode() {
  81                         return ReturnCode.CODE_SUCCESS_CMD;
  82                 }
  83         };
  84
  85         public static final LttngAgentResponse FAILURE_RESPONSE = new LttngAgentResponse() {
  86                 @Override
  87                 public ReturnCode getReturnCode() {
  88                         return ReturnCode.CODE_INVALID_CMD;
  89                 }
  90         };
  91 }