instance-generator

Library capable of generating instances of models (Java POJOs) with field (instance variables) matching pre-defined regular expressions.

Table of content

• Capabilities
• How it works
• Usage
• Future capabilities
• Technologies

Capabilities

TBC

How it works

The library uses regular expressions to generate model fields (instance variables) value. Each field regular expression is supplied via a field level annotation and the data associated with the annotation is read using reflection.

Usage

TBC

Model preparation

Let's consider the following Payment POJO class:

public class Payment {
    
    private String id;
    private String amount;
    private String sender;
    private String receiver;
    private Boolean repeated;
    
    //getters and setters
}

Suppose we want to generate an instance of said class with default values for the fields. In order to be able to do that the model fields should be annotated with the instance-generator specific annotation @Autovalue:

public class Payment {

    @AutoValue(pattern = "[0-9]{9}")
    private String id;

    @AutoValue(pattern = "[0-9]{5,6}\\.[0-9]{2}")
    private String amount;

    @AutoValue(pattern = "[A-Z]{5}")
    private String sender;

    @AutoValue(pattern = "(BO|BA)")
    private String receiver;

    @AutoValue(pattern = "true")
    private Boolean repeated;

    //getters and setters
}

The pattern value of the annotation is where out regex goes.

And that's generally it! We can obtain an instance of this specific class with field values matching the pattern value of the annotation.

Instance generation

The instance generation call is very simple:

InstanceGenerator.of(Payment.class)

Resulting in the following instance:

Payment {
 id=324132662, 
 amount=86006.57, 
 sender='IBQRP', 
 receiver='BO', 
 repeated='true' 
}

Future capabilities

Please be aware that the library is in incipient stages of development, new major features and improvements are to be expected. Including, but not limited to:

• Ability to supply field generation rule (still regex) using external resources (JSON, YML, XML etc.)
• Ability to generate models in in itself from Swagger and GraphQL API definition files
• instance-generator Maven plugin for seamless build lifecycle integration
• ...

Technologies

TBC