stena

Object-Oriented library for protection objects.

Get

Maven

<dependency>
  <groupId>com.github.viise.stena</groupId>
  <artifactId>stena</artifactId>
  <version>1.0.1</version>
</dependency>

Gradle

implementation 'com.github.viise.stena:stena:1.0.1'

What?

When writing code, we often check objects: null or empty, negative or positive, and so on. For example, we can create interface Validator, but interface name Validator for object-oriented world is bad, because we are validating data, not objects. Therefore, we'll not validate objects, but protect it. Interface Wall was creating for protect objects. Now let's think like this: to protect the objects, we will decorate them with the Wall. If the Wall could not protect the objects, then an exception is thrown. Let's look at examples.

Examples

Protect not null object:

String myNotNullObject = "Hello, World!";
Wall<Object> walNotNull = new WalNotNull();
try {
    walNotNull.protect(myNotNullObject);
    // Yay! myNotNullObject is really not null
    // Now you don't have to worry about myNotNullObject is null
} catch (ProtectException e) {
    System.out.println(e.getMessage());
}

Protect positive Integer:

Integer positiveInt = 1;
Wall<Integer> walPositiveInt = new WalPositiveInt();
try {
    walPositiveInt.protect(positiveInt);
} catch (ProtectException e) {
    System.out.println(e.getMessage());
}

For more examples, see tests.

Why?

In order not to write business logic and object checks in the same place. This is primarily necessary for convenient testing. With this approach, you can write a separate test for checking objects, and write a separate test for business logic. Of course, another problem arises here: in order for business logic to work as intended, you also have to remember test for Wall implementation. But with this approach, in the class that implements business logic code that is responsible for business logic will be immediately visible, and will be cleaner than the class with code with business logic, where there is less logic than checks of objects. You need to weigh the pros and cons and understand whether you need to use the Wall at all or not.

Project Name

"stena" is the transliteration of the Russian word "wall" :)