In This Section

Work in Progress

Overview

A Talon XVM has the ability to discover annotated 'Command' methods provided by an application. Such commands can be invoked remotely by tools in an out of band fashion with an application's message driven event handlers to perform administrative functions. The command framework is designed to work in the context of command line tools, guis or for administrative applications. A command method is identified by annotating it with a @Command annotation, and its parameters are exposed by annotating its parameters with either @Option or @Argument annotations which allows commands to be invoked by passing the arguments in a command line format.

  @Command(name = "resetOrderStats", 
           description="Resets the number of orders processed")
  public String resetOrderStats(@Option(shortForm = 'v', longForm ="verbose", defaultValue="false")
                           boolean verbose,
                           @Argument(name = "newOrderReceivedCount"), position=1)
                           long newNumOrdersReceived,
                           @Argument(name = "newOrderProcessingCount", position=2)
                           long newNumOrdersProcessed) { ... }

Annotating Command methods

TODO Describe @Command, @Option, @Argument, and @RemainingArgs

At its simplest, a method that is composed of primitive arguments needs only to be annotated with a Command annotation to expose it as a command that can be invoked remotely.

@App
public void MyApp {
  @AppStat(name = "Orders Processed")
  private volatile long numOrdersProcessed = 0;
 
  /**
   * Resets the number of orders processed
   *
   * @param newNumOrdersProcessed The new number of orders processed 
   * @return The previous number of orders 
   */
  @Command
  public int resetOrdersProcessed(long newNumOrdersProcessed,
                                  boolean verbose) {
    long prevNumOrdersProcessed = numOrdersProcessed;
    numOrdersProcessed = numOrdersProcessed;
    String result = "Reset Orders Processed: " + prevNumOrdersProcessed + "->" + numOrdersProcessed;
    
    if(verbose) {
      System.out.println(result);
    }
   
    return result;
  }
  
  /**
   * Handles a new order. 
   */ 
  @EventHandler
  public final void onOrder(NewOrderMessage newOrder) {
    numOrdersReceived++;
 
	// ... do some processing
 
    numOrdersProcessed++
  }
}

The above method can than be invoked via the Robin api as:

app.invokeCommand("resetOrdersProcessed 0 true")

... the command name is identified by the name of the method and each parameter in the signature is treated as an argument to the command.

@Command

Above we gave a simple example of using the Command annotation to identify a command. The command can be further described by using the following command annotation elements

			Default
aliases	String []	Returns the aliases used to invoke this command. This can be useful in cases where a command's name has change and there is a need to support backwards compatibliity.	none
description		A description of the command. This is used by tools to expose usage information for the command. It is a good idea to provide a description on commands as it provides tools with the ability to provide usage information.	none
name	String	Returns the name of the command. If this parameter is omitted on an annotated Method then the name will default to the method name.	none
parseOptions	boolean	Whether or not the command parser should attempt to parse options or if this command is only comprised of arguments. This can be useful to avoid needing to escape argument values that may start with a '-' character.	true

@Argument

The @Argument annotation can be applied to a method parameters.

@Command(name = "resetOrderStats", 
         description="Resets the number of orders processed")
public int resetOrdersProcessed(@Option(shortForm = 'v', longForm ="verbose", defaultValue="false")
                                boolean verbose,
                                @Argument(name = "newOrderProcessingCount", position=1)
                                long newNumOrdersProcessed)

Supported Types for Options, Arguments And Return values:

The following types are returned when describing the command usage. In Json they are represented as the name from the enumeration below. The expectation is that tools will use this options in forms.

      <enum name="SrvMonArgumentType" type="int">
        <documentation>Enumerates the valid types for command arguments</documentation>
        <const name="BOOLEAN" value="1" />
        <const name="BYTE" value="2" />
        <const name="CHAR" value="3" />
        <const name="SHORT" value="4" />
        <const name="INT" value="5" />
        <const name="LONG" value="6" />
        <const name="FLOAT" value="7" />
        <const name="DOUBLE" value="8" />
        <const name="DATE" value="9" />
        <const name="STRING" value="10" />
      </enum>

      <enum name="SrvMonOptionType" type="int">
        <documentation>Enumerates the valid types for command options</documentation>
        <const name="BOOLEAN" value="1" />
        <const name="BYTE" value="2" />
        <const name="CHAR" value="3" />
        <const name="SHORT" value="4" />
        <const name="INT" value="5" />
        <const name="LONG" value="6" />
        <const name="FLOAT" value="7" />
        <const name="DOUBLE" value="8" />
        <const name="DATE" value="9" />
        <const name="STRING" value="10" />
      </enum>

      <enum name="SrvMonReturnType" type="int">
        <documentation>Enumerates the valid types for command return values</documentation>
        <const name="BOOLEAN" value="1" />
        <const name="BYTE" value="2" />
        <const name="CHAR" value="3" />
        <const name="SHORT" value="4" />
        <const name="INT" value="5" />
        <const name="LONG" value="6" />
        <const name="FLOAT" value="7" />
        <const name="DOUBLE" value="8" />
        <const name="DATE" value="9" />
        <const name="STRING" value="10" />
      </enum>

Command Discovery

The above command could then be discovered as follows:

Robin API

Server server = Controller.getModel().getServer("MyVM");
App app = server.getApp("OrderProcessing");
for (ISrvMonCommandDescription command : app.getCommands()) {
  SrvMonUtil.printCommmandUsage(command, System.out);
  System.out.println();
}

Robin Command Line Tool

>listAppCommands -u MyVM OrderProcessing

Usage

listAppCommands
  This lists the commands available for an app
Usage:
  listAppCommands [-h] [-u] <xvmName> <appName> [<filter>] 
       [<-h|--help> Displays this help message (default='false')]
       [<-u|--usage> Flag that can be specified to additionally show usage
           for the commands. (default='false')]
       xvmName: The name of the XVM in which the app is running
       appName: The name of the app on which to list commands
       [filter: Optionally can be specified to list only commands that
           contain this filter in their name. '*' indicates that all commands
           should be displayed default='*']

Command Invocation

Robin API

The command above can be invoked programmatically using a Robin Controller:

Controller controller = new Controller();
Server server = Controller.getModel().getServer("MyVM");
App orderProcessingApp = server.getApp("OrderProcessing");
System.out.println(app.invokeCommand("resetOrdersProcessed -v true 0"));

Robin Script

instruct the OrderProcessing app in the MyVM xvm to resetOrdersProcessed with -v true 0

Robin Command Line Tool

>invoke MyVM OrderProcessing resetOrdersProcessed -v true 0
SUCCESS: 10000

Escaping

Commands are invoked on the server using a command line style interface in which parameters are passed to the command being executing as option or argument token separated by one or more whitespace characters. The rules for escaping are straightforward:

To pass a string with whitespace as a single token it must be wrapped in quotes for example "My Text" so that the parser can tell that it is one argument rather than two arguments.
- Quotes within a quoted string must be escaped, so to represent an argument "My Text" with the surrounding quotes being passed in the parameter escaped quotes must be used: "\"My Text\""
Because the command parser treats any token starting with '-' as an option negative leading dash characters must be escaped by prefixing them with a '\', for example \-3.1456.

The following simple command serves to demonstrate when escaping is necessary. This command prints a given line to either System.err or System.out:

@Command
public println(@Argument(position= 1, name="text") String line, 
               @Argument(position= 2, name="errorCode", required=false) int errorCode, 
               @Option(shortForm ='e', longForm="error", boolean err) {
  if(err) {
	System.err.println("ERROR [" + errorCode + "]:" + line);
  }
  else {
	System.out.println(line);
  }
}

Passing A String with Spaces

invoke myVM myApp println "My String"

instruct the myApp app in the myVM xvm to println with "My String"

app.invoke("println \"My String\")

The above will result in the following being printed to System.out in the App:

My String

Passing A String with Quotes

Note that below we escape the quote characters within the quoted string:

invoke myVM myApp println -e "\"My Error\""

instruct the myApp app in the myVM xvm to println with -e "\"My Error\""

app.invoke("println -e \"\\"My String\\"\")

All of the above will result in the following being printed to System.error in the App (with the quotes preserved). Not that in the java case that the extra escapes are needed to escape the '\' character.

ERROR [0]: "My Error"

Passing Argument Starting With A Dash

Note that below we escape the quote characters within the quoted string:

invoke myVM myApp println -e \--BAD_TIMES-- \-10

instruct the myApp app in the myVM xvm to println with -e \--BAD_TIMES-- \-10

app.invoke("println -e \--BAD_TIMES-- \-10)

All of the above will result in the following being printed to System.error in the App (with the quotes preserved)

ERROR[-10]: --BAD_TIMES--

Examples

A Fully Annotated Command

    @Command(name = "testCommand", aliases = { "TestCommandAlias" }, description = "A command that exercises all of the invocation APIs")
    public String testCommand(@Option(shortForm = 'b', longForm = "byteOption", required = true, description = "Tests a byte Option", validOptions = { "0,", "1" }, defaultValue = "0") byte aByteOption,
                              @Option(shortForm = 'c', longForm = "charOption", required = true, description = "Tests a char Option", validOptions = { "a,", "b", "c" }, defaultValue = "b") char aCharOption,
                              @Option(shortForm = 'n', longForm = "shortOption", required = true, description = "Tests a short Option", validOptions = { "399,", "300" }, defaultValue = "399") short aShortOption,
                              @Option(shortForm = 'i', longForm = "intOption", required = true, description = "Tests a int Option", validOptions = { "20000,", "200000" }, defaultValue = "200000") int aIntOption,
                              @Option(shortForm = 'l', longForm = "longOption", required = true, description = "Tests a long Option", validOptions = { "100000000,", "2000000000" }, defaultValue = "100000000") long aLongOption,
                              @Option(shortForm = 'f', longForm = "floatOption", required = true, description = "Tests a float Option", validOptions = { "0.0,", "-2.0" }, defaultValue = "0.0") float aFloatOption,
                              @Option(shortForm = 'd', longForm = "doubleOption", required = true, description = "Tests a double Option", validOptions = { "0.0,", "1.2" }, defaultValue = "1.2") double aDoubleOption,
                              @Option(shortForm = 's', longForm = "stringOption", required = true, description = "Tests a String Option", validOptions = { "Foo,", "Bar" }, defaultValue = "Foo") String aStringOption,
                              @Option(shortForm = 'm', longForm = "currencyOption", required = true, description = "Tests a Currency Option", validOptions = { "USD,", "JPY" }, defaultValue = "JPY") Currency aCurrencyOption,
                              @Option(shortForm = 'e', longForm = "enumOption", required = true, description = "Tests a Enum Option", defaultValue = "PrettyPrint") JsonPrettyPrintStyle aEnumOption,
                              @Argument(position = 1, required = true, name = "aByteArgument", description = "Tests a byte Arguement", validOptions = { "0,", "1" }, defaultValue = "0") byte aByteArgument,
                              @Argument(position = 2, required = true, name = "aCharArgument", description = "Tests a char Arguement", validOptions = { "a,", "b", "c" }, defaultValue = "a") char aCharArgument,
                              @Argument(position = 3, required = true, name = "aShortArgument", description = "Tests a short Arguement", validOptions = { "399,", "300" }, defaultValue = "300") short aShortArgument,
                              @Argument(position = 4, required = true, name = "aIntArgument", description = "Tests a int Arguement", validOptions = { "20000,", "200000" }, defaultValue = "200000") int aIntArgument,
                              @Argument(position = 5, required = true, name = "aLongArgument", description = "Tests a long Arguement", validOptions = { "100000000,", "2000000000" }, defaultValue = "100000000") long aLongArgument,
                              @Argument(position = 6, required = true, name = "aFloatArgument", description = "Tests a float Arguement", validOptions = { "0.0,", "-2.01" }, defaultValue = "-2.01") float aFloatArgument,
                              @Argument(position = 7, required = true, name = "aDoubleArgument", description = "Tests a double Arguement", validOptions = { "0.0,", "1.2" }, defaultValue = "0.0") double aDoubleArgument,
                              @Argument(position = 8, required = true, name = "aStringArgument", description = "Tests a String Arguement", validOptions = { "Foo,", "Bar" }, defaultValue = "Foo") String aStringArgument,
                              @Argument(position = 9, required = true, name = "aCurrencyArgument", description = "Tests a Currency Arguement", validOptions = { "USD,", "JPY" }, defaultValue = "USD") Currency aCurrencyArgument,
                              @Argument(position = 10, required = true, name = "aEnumArgument", description = "Tests a Enum Arguement", defaultValue = "Minimal") JsonPrettyPrintStyle aEnumArgument) throws Exception {
        return "Received Arguments: " + Arrays.asList(new Object[] {
                                                                    aByteOption,
                                                                    aCharOption,
                                                                    aShortOption,
                                                                    aIntOption,
                                                                    aLongOption,
                                                                    aFloatOption,
                                                                    aDoubleOption,
                                                                    aStringOption,
                                                                    aCurrencyOption,
                                                                    aEnumOption,
                                                                    aByteArgument,
                                                                    aCharArgument,
                                                                    aShortArgument,
                                                                    aIntArgument,
                                                                    aLongArgument,
                                                                    aFloatArgument,
                                                                    aDoubleArgument,
                                                                    aStringArgument,
                                                                    aCurrencyArgument,
                                                                    aEnumArgument }).toString();
    }

Usage as Printed By SrvMonUtil

testCommand
A command that exercises all of the invocation APIs
 Usage:
  testCommand -b -c -n -i -l -f -d -s -m -e <aByteArgument> <aCharArgument> <aShortArgument> <aIntArgument> <aLongArgument> <aFloatArgument> <aDoubleArgument> <aStringArgument> <aCurrencyArgument> <aEnumArgument> 
       <-b|--byteOption> <1|0,> Tests a byte Option default='0'
       <-c|--charOption> <a,|b|c> Tests a char Option default='b'
       <-n|--shortOption> <300|399,> Tests a short Option default='399'
       <-i|--intOption> <200000|20000,> Tests a int Option default='200000'
       <-l|--longOption> <100000000,|2000000000> Tests a long Option
           default='100000000'
       <-f|--floatOption> <0.0,|-2.0> Tests a float Option default='0.0'
       <-d|--doubleOption> <0.0,|1.2> Tests a double Option default='1.2'
       <-s|--stringOption> <Bar|Foo,> Tests a String Option default='Foo'
       <-m|--currencyOption> <JPY|USD,> Tests a Currency Option
           default='JPY'
       <-e|--enumOption> Tests a Enum Option default='PrettyPrint'
       [aByteArgument: <1|0,> Tests a byte Arguement default='0']
       [aCharArgument: <a,|b|c> Tests a char Arguement default='a']
       [aShortArgument: <300|399,> Tests a short Arguement default='300']
       [aIntArgument: <200000|20000,> Tests a int Arguement
           default='200000']
       [aLongArgument: <100000000,|2000000000> Tests a long Arguement
           default='100000000']
       [aFloatArgument: <0.0,|-2.01> Tests a float Arguement
           default='-2.01']
       [aDoubleArgument: <0.0,|1.2> Tests a double Arguement default='0.0']
       [aStringArgument: <Bar|Foo,> Tests a String Arguement default='Foo']
       [aCurrencyArgument: <JPY|USD,> Tests a Currency Arguement
           default='USD']
       [aEnumArgument: Tests a Enum Arguement default='Minimal']

Json Command Description:

      "name": "testCommand",
      "aliases": [
        "TestCommandAlias"
      ],
      "description": "A command that exercises all of the invocation APIs",
      "arguments": [
        {
          "position": 1,
          "required": true,
          "type": "BYTE",
          "name": "aByteArgument",
          "defaultValue": "0",
          "validValues": [
            "1",
            "0,"
          ],
          "description": "Tests a byte Arguement",
          "_xFieldBitmask_": [
            0
          ],
          "xRogType": 0
        },
        {
          "position": 2,
          "required": true,
          "type": "CHAR",
          "name": "aCharArgument",
          "defaultValue": "a",
          "validValues": [
            "a,",
            "b",
            "c"
          ],
          "description": "Tests a char Arguement",
          "_xFieldBitmask_": [
            0
          ],
          "xRogType": 0
        },
        {
          "position": 3,
          "required": true,
          "type": "SHORT",
          "name": "aShortArgument",
          "defaultValue": "300",
          "validValues": [
            "300",
            "399,"
          ],
          "description": "Tests a short Arguement",
          "_xFieldBitmask_": [
            0
          ],
          "xRogType": 0
        },
        {
          "position": 4,
          "required": true,
          "type": "INT",
          "name": "aIntArgument",
          "defaultValue": "200000",
          "validValues": [
            "200000",
            "20000,"
          ],
          "description": "Tests a int Arguement",
          "_xFieldBitmask_": [
            0
          ],
          "xRogType": 0
        },
        {
          "position": 5,
          "required": true,
          "type": "LONG",
          "name": "aLongArgument",
          "defaultValue": "100000000",
          "validValues": [
            "100000000,",
            "2000000000"
          ],
          "description": "Tests a long Arguement",
          "_xFieldBitmask_": [
            0
          ],
          "xRogType": 0
        },
        {
          "position": 6,
          "required": true,
          "type": "FLOAT",
          "name": "aFloatArgument",
          "defaultValue": "-2.01",
          "validValues": [
            "0.0,",
            "-2.01"
          ],
          "description": "Tests a float Arguement",
          "_xFieldBitmask_": [
            0
          ],
          "xRogType": 0
        },
        {
          "position": 7,
          "required": true,
          "type": "DOUBLE",
          "name": "aDoubleArgument",
          "defaultValue": "0.0",
          "validValues": [
            "0.0,",
            "1.2"
          ],
          "description": "Tests a double Arguement",
          "_xFieldBitmask_": [
            0
          ],
          "xRogType": 0
        },
        {
          "position": 8,
          "required": true,
          "type": "STRING",
          "name": "aStringArgument",
          "defaultValue": "Foo",
          "validValues": [
            "Bar",
            "Foo,"
          ],
          "description": "Tests a String Arguement",
          "_xFieldBitmask_": [
            0
          ],
          "xRogType": 0
        },
        {
          "position": 9,
          "required": true,
          "type": "STRING",
          "name": "aCurrencyArgument",
          "defaultValue": "USD",
          "validValues": [
            "JPY",
            "USD,"
          ],
          "description": "Tests a Currency Arguement",
          "_xFieldBitmask_": [
            0
          ],
          "xRogType": 0
        },
        {
          "position": 10,
          "required": true,
          "type": "STRING",
          "name": "aEnumArgument",
          "defaultValue": "Minimal",
          "description": "Tests a Enum Arguement",
          "_xFieldBitmask_": [
            0
          ],
          "xRogType": 0
        }
      ],
      "options": [
        {
          "shortForm": "b",
          "required": true,
          "type": "BYTE",
          "longForm": "byteOption",
          "defaultValue": "0",
          "validValues": [
            "1",
            "0,"
          ],
          "description": "Tests a byte Option",
          "_xFieldBitmask_": [
            0
          ],
          "xRogType": 0
        },
        {
          "shortForm": "c",
          "required": true,
          "type": "CHAR",
          "longForm": "charOption",
          "defaultValue": "b",
          "validValues": [
            "a,",
            "b",
            "c"
          ],
          "description": "Tests a char Option",
          "_xFieldBitmask_": [
            0
          ],
          "xRogType": 0
        },
        {
          "shortForm": "n",
          "required": true,
          "type": "SHORT",
          "longForm": "shortOption",
          "defaultValue": "399",
          "validValues": [
            "300",
            "399,"
          ],
          "description": "Tests a short Option",
          "_xFieldBitmask_": [
            0
          ],
          "xRogType": 0
        },
        {
          "shortForm": "i",
          "required": true,
          "type": "INT",
          "longForm": "intOption",
          "defaultValue": "200000",
          "validValues": [
            "200000",
            "20000,"
          ],
          "description": "Tests a int Option",
          "_xFieldBitmask_": [
            0
          ],
          "xRogType": 0
        },
        {
          "shortForm": "l",
          "required": true,
          "type": "LONG",
          "longForm": "longOption",
          "defaultValue": "100000000",
          "validValues": [
            "100000000,",
            "2000000000"
          ],
          "description": "Tests a long Option",
          "_xFieldBitmask_": [
            0
          ],
          "xRogType": 0
        },
        {
          "shortForm": "f",
          "required": true,
          "type": "FLOAT",
          "longForm": "floatOption",
          "defaultValue": "0.0",
          "validValues": [
            "0.0,",
            "-2.0"
          ],
          "description": "Tests a float Option",
          "_xFieldBitmask_": [
            0
          ],
          "xRogType": 0
        },
        {
          "shortForm": "d",
          "required": true,
          "type": "DOUBLE",
          "longForm": "doubleOption",
          "defaultValue": "1.2",
          "validValues": [
            "0.0,",
            "1.2"
          ],
          "description": "Tests a double Option",
          "_xFieldBitmask_": [
            0
          ],
          "xRogType": 0
        },
        {
          "shortForm": "s",
          "required": true,
          "type": "STRING",
          "longForm": "stringOption",
          "defaultValue": "Foo",
          "validValues": [
            "Bar",
            "Foo,"
          ],
          "description": "Tests a String Option",
          "_xFieldBitmask_": [
            0
          ],
          "xRogType": 0
        },
        {
          "shortForm": "m",
          "required": true,
          "type": "STRING",
          "longForm": "currencyOption",
          "defaultValue": "JPY",
          "validValues": [
            "JPY",
            "USD,"
          ],
          "description": "Tests a Currency Option",
          "_xFieldBitmask_": [
            0
          ],
          "xRogType": 0
        },
        {
          "shortForm": "e",
          "required": true,
          "type": "STRING",
          "longForm": "enumOption",
          "defaultValue": "PrettyPrint",
          "description": "Tests a Enum Option",
          "_xFieldBitmask_": [
            0
          ],
          "xRogType": 0
        }
      ],
      "_xFieldBitmask_": [
        0
      ],
      "xRogType": 0
    }