# Package org.apache.sis.metadata.iso.maintenance

Information about the frequency and scope of data updates. An explanation for this package is provided in the OpenGIS® javadoc. The remaining discussion on this page is specific to the SIS implementation.
Overview
For a global overview of metadata in SIS, see the `org​.apache​.sis​.metadata` package javadoc.

Package overview
Class hierarchy | Aggregation hierarchy
--- | ---
ISO 19115 metadata `├─` Maintenance information `├─` Scope `└─` Scope description Code list `├─` Maintenance frequency `└─` Scope code | Maintenance information `├─` Maintenance frequency «code list» `└─` Scope `├─` Scope code «code list» `└─` Scope description

Null values, nil objects and collections
All constructors and setter methods accept `null` arguments. A null argument value means that the metadata element can not be provided, and the reason for that is unspecified. Alternatively, users can specify why a metadata element is missing by providing a value created by `NilReason​.createNilObject(Class)`.

Unless otherwise noted in the Javadoc, all getter methods may return an empty collection, an empty array or `null` if the type is neither a collection or an array. Note that non-null values may be `NilObject`s.

Unless the metadata object has been marked as unmodifiable and unless otherwise noted in the Javadoc, all collections returned by getter methods are live: adding new elements in the collection modify directly the underlying metadata object. Noticeable exceptions to this rule are union structures, for which only one property can be non-empty in the same object.

Since:
  0.3

Defined in the `sis-metadata` module

- Class Summary
  Class | Description
  --- | ---
  DefaultMaintenanceInformation | Information about the scope and frequency of updating.
  DefaultScope | The target resource and physical extent for which information is reported.
  DefaultScopeDescription | Description of the class of information covered by the information.
  LegacyFeatureType | Deprecated. To be removed after migration to GeoAPI 4.0.