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         public static final LttngAgentResponse SUCESS_RESPONSE = new LttngAgentResponse() {
  36                 @Override
  37                 public ReturnCode getReturnCode() {
  38                         return ReturnCode.CODE_SUCCESS_CMD;
  39                 }
  40         };
  41
  42         public static final LttngAgentResponse FAILURE_RESPONSE = new LttngAgentResponse() {
  43                 @Override
  44                 public ReturnCode getReturnCode() {
  45                         return ReturnCode.CODE_INVALID_CMD;
  46                 }
  47         };
  48
  49         /**
  50          * Return codes used in agent responses, to indicate success or different
  51          * types of failures of the commands.
  52          */
  53         protected enum ReturnCode {
  54
  55                 CODE_SUCCESS_CMD(1, "sucess"),
  56                 CODE_INVALID_CMD(2, "invalid"),
  57                 CODE_UNKNOWN_LOGGER_NAME(3, "unknown logger name");
  58
  59                 private final int code;
  60                 private final String toString;
  61
  62                 private ReturnCode(int c, String str) {
  63                         code = c;
  64                         toString = str;
  65                 }
  66
  67                 public int getCode() {
  68                         return code;
  69                 }
  70
  71                 /**
  72                  * Mainly used for debugging. The strings are not sent through the
  73                  * socket.
  74                  */
  75                 @Override
  76                 public String toString() {
  77                         return toString;
  78                 }
  79         }
  80
  81         /**
  82          * Get the {@link ReturnCode} that goes with this response. It is expected
  83          * by the session daemon, but some commands may require more than this
  84          * in their response.
  85          *
  86          * @return The return code
  87          */
  88         public abstract ReturnCode getReturnCode();
  89
  90         /**
  91          * Gets a byte array of the response so that it may be streamed.
  92          *
  93          * @return The byte array of the response
  94          */
  95         public byte[] getBytes() {
  96                 byte data[] = new byte[INT_SIZE];
  97                 ByteBuffer buf = ByteBuffer.wrap(data);
  98                 buf.order(ByteOrder.BIG_ENDIAN);
  99                 buf.putInt(getReturnCode().getCode());
 100                 return data;
 101         }
 102
 103         @Override
 104         public String toString() {
 105                 return "LttngAgentResponse["
 106                                 + "code=" + getReturnCode().getCode()
 107                                 + ", " + getReturnCode().toString()
 108                                 + "]";
 109         }
 110 }