README
¶
Value Object Generator
Overview
The Value Object Generator is a tool for generating value objects in the ServiceLib library. It generates code for both string-based and struct-based value objects, along with their corresponding test files.
Usage
Command-Line Tool
The generator can be used as a command-line tool:
go run cmd/generate/main.go -config path/to/config.json -templates path/to/templates -output path/to/output
Options:
-config: Path to the configuration file (required)-templates: Directory containing the templates (default: "templates")-output: Directory where the generated code will be written (default: ".")
Configuration File
The configuration file is a JSON file that contains an array of value object configurations. Each configuration has the following fields:
Name: The name of the value object (e.g., "Email")Package: The package name (e.g., "contact")Type: The type of value object ("string" or "struct")BaseType: The base type for string-based value objects (e.g., "string")Description: A description of the value objectFields: A map of field names to field types (for struct-based value objects)Validations: A map of field names to validation functionsImports: A list of additional imports
Example configuration file:
[
{
"Name": "PostalCode",
"Package": "contact",
"Type": "string",
"BaseType": "string",
"Description": "a postal code value object",
"Validations": {
"PostalCode": "if len(trimmedValue) < 5 {\n\t\treturn \"\", errors.New(\"postal code is too short\")\n\t}\n\n\tif len(trimmedValue) > 10 {\n\t\treturn \"\", errors.New(\"postal code is too long\")\n\t}"
},
"Imports": []
},
{
"Name": "Currency",
"Package": "measurement",
"Type": "struct",
"Description": "a currency value object",
"Fields": {
"Code": "string",
"Symbol": "string",
"Name": "string"
},
"Validations": {
"Code": "if v.Code == \"\" {\n\t\treturn errors.New(\"currency code cannot be empty\")\n\t}\n\n\tif len(v.Code) != 3 {\n\t\treturn errors.New(\"currency code must be 3 characters\")\n\t}",
"Symbol": "if v.Symbol == \"\" {\n\t\treturn errors.New(\"currency symbol cannot be empty\")\n\t}"
},
"Imports": [
"errors"
]
}
]
Programmatic Usage
The generator can also be used programmatically:
import "github.com/abitofhelp/servicelib/valueobject/generator"
func main() {
// Create a generator
gen := generator.NewGenerator("templates", "output")
// Create a value object configuration
config := generator.ValueObjectConfig{
Name: "Email",
Package: "contact",
Type: generator.StringBased,
BaseType: "string",
Description: "an email address value object",
Validations: map[string]string{
"Email": `if !strings.Contains(trimmedValue, "@") {
return "", errors.New("invalid email format: missing @ symbol")
}`,
},
Imports: []string{"errors"},
}
// Generate the value object
if err := gen.Generate(config); err != nil {
panic(err)
}
}
Templates
The generator uses the following templates:
string_value_object.tmpl: Template for string-based value objectsstring_value_object_test.tmpl: Template for string-based value object testsstruct_value_object.tmpl: Template for struct-based value objectsstruct_value_object_test.tmpl: Template for struct-based value object tests
These templates are located in the templates directory.
Generated Code
The generator generates the following files for each value object:
<package>/<name>.go: The value object implementation<package>/<name>_test.go: The value object tests
The generated code follows the ServiceLib coding standards and includes:
- A constructor function that validates the input and returns a new instance
- Methods for String(), Equals(), IsEmpty(), and Validate()
- Additional methods for struct-based value objects: ToMap() and MarshalJSON()
- Comprehensive tests for all methods
Documentation
¶
Overview ¶
Package generator provides code generation tools for value objects.
Package generator provides code generation tools for value objects.
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
Types ¶
type GenerateCommand ¶
type GenerateCommand struct {
// ConfigFile is the path to the configuration file.
ConfigFile string
// TemplateDir is the directory containing the templates.
TemplateDir string
// OutputDir is the directory where the generated code will be written.
OutputDir string
}
GenerateCommand is a command-line tool for generating value objects.
func NewGenerateCommand ¶
func NewGenerateCommand() *GenerateCommand
NewGenerateCommand creates a new GenerateCommand.
func (*GenerateCommand) ParseFlags ¶
func (c *GenerateCommand) ParseFlags()
ParseFlags parses the command-line flags.
type Generator ¶
type Generator struct {
// TemplateDir is the directory containing the templates.
TemplateDir string
// OutputDir is the directory where the generated code will be written.
OutputDir string
}
Generator generates code for value objects.
func NewGenerator ¶
NewGenerator creates a new Generator.
func (*Generator) Generate ¶
func (g *Generator) Generate(config ValueObjectConfig) error
Generate generates code for a value object.
type ValueObjectConfig ¶
type ValueObjectConfig struct {
// Name is the name of the value object (e.g., "Email").
Name string
// Package is the package name (e.g., "contact").
Package string
// Type is the type of value object (string or struct).
Type ValueObjectType
// Fields is a map of field names to field types (for struct-based value objects).
Fields map[string]string
// Validations is a map of field names to validation functions.
Validations map[string]string
// Imports is a list of additional imports.
Imports []string
// BaseType is the base type for string-based value objects (e.g., "string").
BaseType string
// Description is a description of the value object.
Description string
}
ValueObjectConfig contains the configuration for generating a value object.
type ValueObjectType ¶
type ValueObjectType string
ValueObjectType represents the type of value object to generate.
const ( // StringBased represents a string-based value object. StringBased ValueObjectType = "string" // StructBased represents a struct-based value object. StructBased ValueObjectType = "struct" )
Source Files