JMock

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Introduction

JMock is a high-performance data generation and simulation library implemented in Java. It generates data that more closely resembles real business data characteristics compared to random data generation.

Core Features

• High-performance data generation:
  Generates 2M+ user records per second (single thread). Each record contains 10+ attributes totaling 200+ bytes.
• Business-realistic data with i18n support:
  Produces data that accurately simulates real-world business scenarios with internationalization capabilities.
• Dual definition approaches:
  • Annotation-based: Applied to class fields
  • Function-based: Used in script files (txt, json, yml, etc.)
• Multiple storage options:
  Supports JDBC, in-memory, and local filesystem persistence for batch data.
• Extensible architecture:
  Plugin-based system for custom mock data functions.

Function Expressions

Expression Formats

Type	Parameterless Form	Parameterized Form
Annotation	@Annotation	@Annotation(param1=value1, param2=value2)
Function	@Function()	@Function(param1, param2) or @Function(param1,,param3)

Syntax Rules

1. Core Symbols

   • @ - Marks expression start
   • () - Encloses parameters
   • , - Separates parameters
   • | - Delimits array elements (array parameters only)
   • \ - Escapes special characters (@, ,, |)

2. Naming Conventions

   • Annotation/Function Names: UpperCamelCase
     Example: EmailValidator, RandomNumber
   • Parameter Names: lowerCamelCase
     Example: minValue, maxLength

3. Parameter Rules

   • Parameterless calls: Omit parentheses (annotations) or use empty () (functions)
   • Parameterized calls:
     • Annotation: param=value key-value pairs
     • Function: Positional values
   • Omitted parameters: Preserve commas
     Example: @Generate(1,,3) indicates empty second parameter

4. Special Character Handling
   Escape @, ,, | in parameter values:
   Example: @String("tom\@domain.com\|nick\@domain.com")

Usage Example

1. Add Maven Dependency

<dependency>
   <groupId>cloud.xcan.jmock</groupId>
   <artifactId>xcan-jmock.core</artifactId>
   <version>1.0.0</version>
</dependency>

2. Generate Sample Data

// Define template
String content = """
    {
      "name": "@Name()",
      "email": "@Email()",
      "phone": "@Mobile()",
      "address": "@Address()",
      "hobbies": [ "reading", "hiking",  "cooking" ]
    }""";
    
// Process mock functions
String result = new DefaultMockTextReplacer().replace(content);

// Output result
System.out.println(result);

Output:

{
  "name": "Durfee Jacob",
  "email": "9alJWYsUGJuJZtGuXT@yahoo.com.cn",
  "phone": "15292153757",
  "address": "ul. Akademika Pavlova, 12к3, Moskva",
  "hobbies": [ "reading", "hiking",  "cooking" ]
}