Module org.apache.sis.feature
Package org.apache.sis.feature

Class DefaultFeatureType

Object
AbstractIdentifiedType
DefaultFeatureType
All Implemented Interfaces:
Serializable, Deprecable
public class DefaultFeatureType extends AbstractIdentifiedType
Abstraction of a real-world phenomena. A Feature­Type instance describes the class of all feature instances of that type.
Analogy: compared to the Java language, Feature­Type is equivalent to Class while Feature instances are equivalent to Object instances of that class.
Warning: This class is expected to implement a GeoAPI Feature­Type interface in a future version. When such interface will be available, most references to Default­Feature­Type in the API will be replaced by references to the Feature­Type interface.

Naming

The feature type name is mandatory and should be unique. Those names are the main criterion used for deciding if a feature type is assignable from another type. Names can be scoped for avoiding name collision.

Properties and inheritance

Each feature type can provide descriptions for the following properties: In addition, a feature type can inherit the properties of one or more other feature types. Properties defined in the sub-type can override properties of the same name defined in the super-types, provided that values of the sub-type property are assignable to the super-type property.
Analogy: compared to the Java language, the above rule is similar to overriding a method with a more specific return type (a.k.a. covariant return type). This is also similar to Java arrays, which are implicitly covariant (i.e. String[] can be casted to Char­Sequence[], which is safe for read operations but not for write operations — the latter may throw Array­Store­Exception).

Instantiation

Default­Feature­Type can be instantiated directly by a call to its constructor. But a more convenient approach may be to use the Feature­Type­Builder instead, which provides shortcuts for frequently-used operations like creating various Generic­Name instances sharing the same namespace.

Immutability and thread safety

Instances of this class are immutable if all properties (Generic­Name and International­String instances) and all arguments (Attribute­Type instances) given to the constructor are also immutable. Such immutable instances can be shared by many objects and passed between threads without synchronization.
Since:
0.5
See Also:

  • Constructor Details

  • Method Details

    • isAbstract

      public final boolean isAbstract()
      Returns true if the feature type acts as an abstract super-type. Abstract types cannot be instantiated.
      Returns:
      true if the feature type acts as an abstract super-type.

    • isSimple

      public boolean isSimple()
      Returns true if this feature type contains only attributes with [1 … 1] multiplicity, or operations (no feature association). Such feature types can be handled as a records.
      Returns:
      true if this feature type contains only simple attributes or operations.

    • isAssignableFrom

      public boolean isAssignableFrom(DefaultFeatureType type)
      Returns true if this type is same or a super-type of the given type. The check is based mainly on the feature type name, which should be unique. However, as a safety, this method also checks that all properties in this feature type is assignable from a property of the same name in the given type.

      Constraints

      • If A is assignable from B and B is assignable from C, then A is assignable from C.
      Analogy: if we compare Feature­Type to Class in the Java language, then this method is equivalent to Class​.is­Assignable­From(Class).
      Parameters:
      type - the type to be checked.
      Returns:
      true if instances of the given type can be assigned to association of this type.

    • getSuperTypes

      public final Set<DefaultFeatureType> getSuperTypes()
      Returns the direct parents of this feature type.
      Analogy: if we compare Feature­Type to Class in the Java language, then this method is equivalent to Class​.get­Superclass() except that feature types allow multi-inheritance.
      Warning: The type of list elements will be changed to Feature­Type if and when such interface will be defined in GeoAPI.

      API note

      This method is final because it is invoked (indirectly) by constructors, and invoking a user-overrideable method at construction time is not recommended. Furthermore, many Apache SIS methods need guarantees about the stability of this collection.
      Returns:
      the parents of this feature type, or an empty set if none.

    • getProperties

      public Collection<AbstractIdentifiedType> getProperties(boolean includeSuperTypes)
      Returns any feature operation, any feature attribute type and any feature association role that carries characteristics of a feature type. The returned collection will include the properties inherited from the super-types only if include­Super­Types is true.
      Warning: The type of list elements will be changed to Property­Type if and when such interface will be defined in GeoAPI.
      Parameters:
      include­Super­Types - true for including the properties inherited from the super-types, or false for returning only the properties defined explicitly in this type.
      Returns:
      feature operation, attribute type and association role that carries characteristics of this feature type (not including parent types).

    • getProperty

      public AbstractIdentifiedType getProperty(String name) throws IllegalArgumentException
      Returns the attribute, operation or association role for the given name.
      Warning: The type of returned element will be changed to Property­Type if and when such interface will be defined in GeoAPI.
      Parameters:
      name - the name of the property to search.
      Returns:
      the property for the given name, or null if none.
      Throws:
      Illegal­Argument­Exception - if the given argument is not a property name of this feature.
      See Also:

    • newInstance

      public AbstractFeature newInstance() throws IllegalStateException
      Creates a new feature instance of this type.
      Analogy: if we compare Feature­Type to Class and Feature to Object in the Java language, then this method is equivalent to Class​.new­Instance().
      Returns:
      a new feature instance.
      Throws:
      Illegal­State­Exception - if this feature type is abstract.

    • hashCode

      public int hashCode()
      Returns a hash code value for this feature type.
      Overrides:
      hash­Code in class Abstract­Identified­Type
      Returns:
      the hash code for this type.

    • equals

      public boolean equals(Object obj)
      Compares this feature type with the given object for equality.
      Overrides:
      equals in class Abstract­Identified­Type
      Parameters:
      obj - the object to compare with this type.
      Returns:
      true if the given object is equal to this type.

    • toString

      public String toString()
      Formats this feature in a tabular format.
      Overrides:
      to­String in class Object
      Returns:
      a string representation of this feature in a tabular format.
      See Also:

    • getName

      GenericName getName()