# Schema-Aware XQuery from Java

When queries are controlled using the Java API, the equivalent to the `-val` option is to create a `SchemaAwareConfiguration` instead of a `Configuration` object, and then to call `setSchemaValidation(net.sf.saxon.om.Validation.STRICT)` on this object. The value `Validation.LAX` can also be used.

This option switches validation on for all source documents used by any transformation under the control of this `SchemaAwareConfiguration`. If you want finer control, so that some documents are validated and others are not, you can achieve this by using the `AugmentedSource` object. An `AugmentedSource` is a wrapper around a normal JAXP `Source` object, in which additional properties can be set: for example, a property to request validation of the document. The `AugmentedSource` itself implements the JAXP `Source` interface, so it can be used anywhere that an ordinary `Source` object can be used, for example as the first argument to the `buildDocument()` method of the `QueryProcessor`, and as the return value from a user-written `URIResolver`.

The `Configuration` method `setValidationWarnings()` has the same effect as the `-vw` option on the command line: validation errors encountered when processing the final result tree are reported to the `ErrorListener` as warnings, not as fatal errors. They are also reported as XML comments in the result tree.

Schemas can be loaded using either of the techniques used with the command-line interface: that is, by specifying them in the `import schema` directive in the query prolog, or by including them in an `xsi:schemaLocation` attribute in a source document. In addition, they can be loaded using the `addSchema()` method on the `SchemaAwareConfiguration` class.

All schemas that are loaded are cached as part of the `SchemaAwareConfiguration`. This is true whether the schema is loaded explicitly using the Java API, whether it is loaded as a result of `import schema` in a query, or whether it is referenced in an `xsi:schemaLocation` attribute in a source document. There can only be one schema document loaded for each namespace: any further attempts to load a schema for a given target namespace will return the existing loaded schema, rather than loading a new one. Note in particular that this means there can only be one loaded no-namespace schema document. If you want to force loading of a different schema document for an existing namespace, the only way to do it is to create a new `SchemaAwareConfiguration`.

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