Package org.pipservices3.commons.commands

Class Command

java.lang.Object

org.pipservices3.commons.commands.Command

All Implemented Interfaces:

ICommand, IExecutable

public class Command
extends Object
implements ICommand

Concrete implementation of ICommand interface. Command allows to call a method or function using Command pattern.

### Example ###

 
 Command command = new Command("add", null, (args) -> {
     float param1 = args.getAsFloat("param1");
     float param2 = args.getAsFloat("param2");
     return param1 + param2;
 });

 Object result = command.execute(
   "123",
   Parameters.fromTuples(
     "param1", 2,
     "param2", 2
   )
 );

 System.out.println(result.toString());

 // Console output: 4
 
 

See Also:

• ICommand
• CommandSet

Constructor Summary

Constructors

Constructor	Description
Command(String name, Schema schema, IExecutable function)	Creates a new command object and assigns it's parameters.

Method Summary

Modifier and Type	Method	Description
Object	execute(String correlationId, Parameters args)	Executes the command.
String	getName()	Gets the command name.
List<ValidationResult>	validate(Parameters args)	Validates the command Parameters args before execution using the defined schema.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

Command

public Command(String name,
 Schema schema,
 IExecutable function)

Creates a new command object and assigns it's parameters.

Parameters:

name - the name of the command

schema - a validation schema for command arguments

function - an execution function to be wrapped into this command.

Method Details

getName

public String getName()

Gets the command name.

Specified by:

getName in interface ICommand

Returns:

the command name

execute

public Object execute(String correlationId,
 Parameters args)
               throws ApplicationException

Executes the command. Before execution is validates Parameters args using the defined schema. The command execution intercepts ApplicationException raised by the called function and throws them.

Specified by:

execute in interface IExecutable

Parameters:

correlationId - optional transaction id to trace calls across components.

args - the parameters (arguments) to pass to this command for execution.

Returns:

execution result.

Throws:

ApplicationException - when execution fails for whatever reason.

See Also:

• Parameters

validate

public List<ValidationResult> validate(Parameters args)

Validates the command Parameters args before execution using the defined schema.

Specified by:

validate in interface ICommand

Parameters:

args - the parameters (arguments) to validate using this command's schema.

Returns:

a list ValidationResults or an empty list (if no schema is set).

See Also:

• Parameters
• ValidationResult