# Document.Namespace

Artifact: [androidx.appsearch:appsearch](https://developer.android.com/jetpack/androidx/releases/appsearch) [View Source](https://cs.android.com/search?q=file:androidx/appsearch/annotation/Document.java+class:androidx.appsearch.annotation.Document.Namespace) Added in [1.1.0](https://developer.android.com/jetpack/androidx/releases/appsearch#1.1.0)

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```
@Documented
@Retention(value = RetentionPolicy.CLASS)
@Target(value = [ElementType.FIELD, ElementType.METHOD])
annotation Document.Namespace
```

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Marks a member field of a document as the document's namespace.

The namespace is an arbitrary user-provided string that can be used to group documents during querying or deletion. Indexing a document with a particular ID replaces any existing documents with the same ID in that namespace.

A document must have exactly one such field, and it must be of type `https://developer.android.com/reference/java/lang/String.html`.

See the class description of `https://developer.android.com/reference/kotlin/androidx/appsearch/annotation/Document` for other requirements (i.e. if present it must be visible, or have a visible getter and setter, or be exposed through a visible constructor).