# Verify Classes

Konsist enables development teams to enforce structural rules for class ensuring code consistency across projects.

To verify classes start by querying all classes present in the project:

```kotlin
Konsist
.scopeFromProject()
.classes()
...
```

{% hint style="info" %}
The above code selects all classes present in the project codebase. While this demonstrates Konsist's API capabilities, in practical scenarios you'll typically want to verify a specific subset of classes - such as those with a particular name suffix or classes within a given package. See [Create The Scope](/writing-tests/koscope.md) and [Declaration Filtering](/writing-tests/declaration-query-and-filter.md). 
{% endhint %}

Konsist allows you to verify multiple aspects of a class. For a complete understanding of the available APIs, refer to the language reference documentation for [KoClassDeclaration](https://lemonappdev.github.io/konsist/-konsist%200.17.0/com.lemonappdev.konsist.api.declaration/-ko-class-declaration/index.html).

Let's look at few examples.

## Verify Name

Class names can be validated to ensure they follow project naming conventions and patterns.

Check if class name ends with `Repository`:

```kotlin
...
.assertTrue {
   it.hasNameEndingWith("Repository")
}
```

## Verify Modifiers

Class modifiers can be validated to ensure proper encapsulation and access control.

Check if class has `internal` modifier:

```kotlin
...
.assertTrue {
   it.hasInternalModifier
}
```

## Verify Annotations

Class-level and member annotations can be verified for presence, correct usage, and required attribute values.

Check if class is annotated with `Service` annotation:

```kotlin
...
.assertTrue {
   it.hasAnnotationOf(Service::class)
}
```

## Verify Package

Package declarations can be validated to ensure classes are located in the correct package structure according to architectural guidelines.

Check if class has `model` package or sub-packages (`..` means include sub-packages):

```kotlin
...
.assertTrue {
   it.resideInPackage("com.lemonappdev.model..")
}
```

## Verify Methods

Methods can be validated for their signatures, modifiers, annotations, naming patterns, return types, and parameter structures.

Check if methods (functions defined inside class) have no annotations:

```kotlin
...
.functions()
.assertTrue {
   it.annotations.isEmpty()
}
```

See [Broken mention](broken://pages/jgKJIDKGqg3dksBBo5Nl).

## Verify Properties

Properties can be checked for proper access modifiers, type declarations, and initialization patterns.

Check if all properties (defined inside class) has `val` modifiers:

```kotlin
...
.properties()
.assertTrue {
   it.isVal
}
```

See [#verify-properties](#verify-properties "mention").

## Verify Constructors

Primary and secondary constructors can be validated for parameter count, types, and proper initialization.

Check if class has explicit primary constructor:

```kotlin
...
.assertTrue {
   it.hasPrimaryConstructor
}
```

Check if primary constructor is annotated with `Inject` annotation:

```kotlin
...
.primaryConstructors
.assertTrue {
    it.hasAnnotation(Inject::class)
}
```

## Verify Generic Type Parameters

Generic type parameters and constraints can be checked for correct usage and bounds declarations.

Check if class has not type parameters:

<pre class="language-kotlin"><code class="lang-kotlin">...
.assertFalse {
<strong>    it.hasTypeParameters()
</strong>}
</code></pre>

## Verify Generic Type Arguments

Generic type arguments can be checked for correct usage.

Check if parent has no type arguments:

```kotlin
...
.parents()
.assertFalse {
    it.hasTypeArguments()
}
```

## Verify Parents

Inheritance hierarchies, interfaces implementations, and superclass relationships can be validated.

Check if class extends `CrudRepository`:

```kotlin
...
.assertTrue {
   it.hasParentOf(CrudRepository::class)
}
```

## Verify Companion Objects

Companion object declarations, their contents, and usage patterns can be verified for compliance.

Check if class has companion object:

```kotlin
...
.assertTrue { declaration ->
    declaration.hasObject { it.hasCompanionModifier }
}
```

## Verify Members Order

The sequential arrangement of class members can be enforced according to defined organizational rules.

Check if class properties are defined before functions:

```kotlin
...
.assertTrue {
    val lastKoPropertyDeclarationIndex = it
        .declarations(includeNested = false, includeLocal = false)
        .indexOfLastInstance<KoPropertyDeclaration>()
    
    val firstKoFunctionDeclarationIndex = it
        .declarations(includeNested = false, includeLocal = false)
        .indexOfFirstInstance<KoFunctionDeclaration>()
    
    if (lastKoPropertyDeclarationIndex != -1 && firstKoFunctionDeclarationIndex != -1) {
        lastKoPropertyDeclarationIndex < firstKoFunctionDeclarationIndex
    } else {
        true
    }
}
```


---

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Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.konsist.lemonappdev.com/veryfying-codebase/verify-classes.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.