# A2uiBasicCatalogV1.CheckRule

Artifact: [androidx.a2ui.compose:compose-ui](https://developer.android.com/jetpack/androidx/releases/a2ui-compose) [View Source](https://cs.android.com/search?q=file:androidx/a2ui/compose/ui/catalog/A2uiBasicCatalogV1.kt+class:androidx.a2ui.compose.ui.catalog.A2uiBasicCatalogV1.CheckRule) Added in [1.0.0-alpha02](https://developer.android.com/jetpack/androidx/releases/a2ui-compose#1.0.0-alpha02)


```
class A2uiBasicCatalogV1.CheckRule
```

<br />

*** ** * ** ***

Holds the evaluated result of a client-side validation rule.

Check rules define client-side constraints evaluated against dynamic data or user input. Components receive evaluated rules in `TypedContent` to show validation feedback or guard actions.

**Common Use Cases:**

- **Input validation feedback** : Input components (e.g., `https://developer.android.com/reference/kotlin/androidx/a2ui/compose/ui/catalog/A2uiBasicCatalogV1.TextField`, `https://developer.android.com/reference/kotlin/androidx/a2ui/compose/ui/catalog/A2uiBasicCatalogV1.DateTimeInput`, `https://developer.android.com/reference/kotlin/androidx/a2ui/compose/ui/catalog/A2uiBasicCatalogV1.Slider`, `https://developer.android.com/reference/kotlin/androidx/a2ui/compose/ui/catalog/A2uiBasicCatalogV1.CheckBox`, `https://developer.android.com/reference/kotlin/androidx/a2ui/compose/ui/catalog/A2uiBasicCatalogV1.ChoicePicker`) inspect `https://developer.android.com/reference/kotlin/androidx/a2ui/compose/ui/catalog/A2uiBasicCatalogV1.CheckRule#condition()`. When `false`, the component enters an error state (such as an error outline or icon) and displays `https://developer.android.com/reference/kotlin/androidx/a2ui/compose/ui/catalog/A2uiBasicCatalogV1.CheckRule#message()` in supporting or helper text.

- **Action gating and submit prevention** : Action components (e.g., `https://developer.android.com/reference/kotlin/androidx/a2ui/compose/ui/catalog/A2uiBasicCatalogV1.Button`) inspect `https://developer.android.com/reference/kotlin/androidx/a2ui/compose/ui/catalog/A2uiBasicCatalogV1.CheckRule#condition()` across form fields. When any rule fails, the button disables action dispatch or shows `https://developer.android.com/reference/kotlin/androidx/a2ui/compose/ui/catalog/A2uiBasicCatalogV1.CheckRule#message()` explaining why the action cannot run.

- **Cross-component dependency validation**: Check conditions observe shared data model paths to enforce relational constraints (e.g., verifying an end date succeeds a start date, or requiring a checkbox to be checked before submitting).

When all checks have `https://developer.android.com/reference/kotlin/androidx/a2ui/compose/ui/catalog/A2uiBasicCatalogV1.CheckRule#condition()` equal to `true` (or the list is empty), the component is valid and renders normally. If dynamic check expressions are still resolving, the component waits in a loading state until all bound paths resolve.

## Summary

| ### Public constructors |
|---|
| `https://developer.android.com/reference/kotlin/androidx/a2ui/compose/ui/catalog/A2uiBasicCatalogV1.CheckRule#CheckRule(kotlin.Boolean,kotlin.String)(condition: https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-boolean/index.html, message: https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-string/index.html)` |

| ### Public functions |
|---|---|
| `open operator https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-boolean/index.html` | `https://developer.android.com/reference/kotlin/androidx/a2ui/compose/ui/catalog/A2uiBasicCatalogV1.CheckRule#equals(kotlin.Any)(other: https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-any/index.html?)` |
| `open https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-int/index.html` | `https://developer.android.com/reference/kotlin/androidx/a2ui/compose/ui/catalog/A2uiBasicCatalogV1.CheckRule#hashCode()()` |
| `open https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-string/index.html` | `https://developer.android.com/reference/kotlin/androidx/a2ui/compose/ui/catalog/A2uiBasicCatalogV1.CheckRule#toString()()` |

| ### Public properties |
|---|---|
| `https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-boolean/index.html` | `https://developer.android.com/reference/kotlin/androidx/a2ui/compose/ui/catalog/A2uiBasicCatalogV1.CheckRule#condition()` true if the check passed; false if the validation rule failed |
| `https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-string/index.html` | `https://developer.android.com/reference/kotlin/androidx/a2ui/compose/ui/catalog/A2uiBasicCatalogV1.CheckRule#message()` error message to display when `https://developer.android.com/reference/kotlin/androidx/a2ui/compose/ui/catalog/A2uiBasicCatalogV1.CheckRule#condition()` is false |

## Public constructors

### CheckRule

Added in [1.0.0-alpha02](https://developer.android.com/jetpack/androidx/releases/a2ui-compose#1.0.0-alpha02)

```
CheckRule(condition: Boolean, message: String)
```

## Public functions

### equals

```
open operator fun equals(other: Any?): Boolean
```

### hashCode

```
open fun hashCode(): Int
```

### toString

```
open fun toString(): String
```

## Public properties

### condition

Added in [1.0.0-alpha02](https://developer.android.com/jetpack/androidx/releases/a2ui-compose#1.0.0-alpha02)

```
val condition: Boolean
```

true if the check passed; false if the validation rule failed

### message

Added in [1.0.0-alpha02](https://developer.android.com/jetpack/androidx/releases/a2ui-compose#1.0.0-alpha02)

```
val message: String
```

error message to display when `https://developer.android.com/reference/kotlin/androidx/a2ui/compose/ui/catalog/A2uiBasicCatalogV1.CheckRule#condition()` is false