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

Class DefaultAssociationRole

Object
AbstractIdentifiedType
DefaultAssociationRole
All Implemented Interfaces:
Serializable, Deprecable
public class DefaultAssociationRole extends AbstractIdentifiedType
Indicates the role played by the association between two features. In the area of geographic information, there exist multiple kinds of associations:
  • Aggregation represents associations between features which can exist even if the aggregate is destroyed.
  • Composition represents relationships where the owned features are destroyed together with the composite.
  • Spatial association represents spatial or topological relationships that may exist between features (e.g. “east of”).
  • Temporal association may represent for example a sequence of changes over time involving the replacement of some feature instances by other feature instances.

Immutability and thread safety

Instances of this class are immutable if all properties (Generic­Name and International­String instances) and all arguments (e.g. value­Type) 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

    • DefaultAssociationRole

      public DefaultAssociationRole(Map<String,?> identification, DefaultFeatureType valueType, int minimumOccurs, int maximumOccurs)
      Constructs an association to the given feature type. The properties map is given unchanged to the super-class constructor. The following table is a reminder of main (not all) recognized map entries:
      Recognized map entries (non exhaustive list)
      Map key Value type Returned by
      "name" GenericName or String AbstractIdentifiedType.getName()
      "definition" InternationalString or String AbstractIdentifiedType.getDefinition()
      "designation" InternationalString or String AbstractIdentifiedType.getDesignation()
      "description" InternationalString or String AbstractIdentifiedType.getDescription()
      "deprecated" Boolean AbstractIdentifiedType.isDeprecated()
      Parameters:
      identification - the name and other information to be given to this association role.
      value­Type - the type of feature values.
      minimum­Occurs - the minimum number of occurrences of the association within its containing entity.
      maximum­Occurs - the maximum number of occurrences of the association within its containing entity, or Integer​.MAX_VALUE if there is no restriction.
      See Also:

    • DefaultAssociationRole

      public DefaultAssociationRole(Map<String,?> identification, GenericName valueType, int minimumOccurs, int maximumOccurs)
      Constructs an association to a feature type of the given name. This constructor can be used when creating a cyclic graph of Default­Feature­Type instances. In such cases, at least one association needs to be created while its Feature­Type is not yet available.

      Example

      The following establishes a bidirectional association between feature types A and B: 
      String    namespace = "My model";
GenericName nameOfA = Names.createTypeName(namespace, ":", "Feature type A");
GenericName nameOfB = Names.createTypeName(namespace, ":", "Feature type B");
FeatureType typeA = new DefaultFeatureType(Map.of(NAME_KEY, nameOfA), false, null,
    new DefaultAssociationRole(Map.of(NAME_KEY, "Association to B"), nameOfB, 1, 1),
    // More properties if desired.
);
FeatureType typeB = new DefaultFeatureType(Map.of(NAME_KEY, nameOfB), false, null,
    new DefaultAssociationRole(Map.of(NAME_KEY, "Association to A"), featureA, 1, 1),
    // More properties if desired.
);
      After the above code completed, the value type of "association to B" has been automatically set to the type­B instance. Callers shall make sure that the feature types graph will not contain more than one feature of the given name. If more than one Feature­Type instance of the given name is found at resolution time, the selected one is undetermined.
      Parameters:
      identification - the name and other information to be given to this association role.
      value­Type - the name of the type of feature values.
      minimum­Occurs - the minimum number of occurrences of the association within its containing entity.
      maximum­Occurs - the maximum number of occurrences of the association within its containing entity, or Integer​.MAX_VALUE if there is no restriction.

  • Method Details

    • isResolved

      public final boolean isResolved()
      Returns true if the associated Feature­Type is complete (not just a name). This method returns false if this Feature­Association­Role has been constructed with only a feature name and that named feature has not yet been resolved.
      Returns:
      true if the associated feature is complete, or false if only its name is known.
      Since:
      0.8
      See Also:

    • getValueType

      public final DefaultFeatureType getValueType()
      Returns the type of feature values.

      This method cannot be invoked if is­Resolved() returns false. However, it is still possible to get the associated feature type name.

      Warning: In a future SIS version, the return type may be changed to org​.opengis​.feature​.Feature­Type. This change is pending GeoAPI revision.
      Returns:
      the type of feature values.
      Throws:
      Illegal­State­Exception - if the feature type has been specified only by its name and not yet resolved.
      See Also:

    • getMinimumOccurs

      public final int getMinimumOccurs()
      Returns the minimum number of occurrences of the association within its containing entity. The returned value is greater than or equal to zero.
      Returns:
      the minimum number of occurrences of the association within its containing entity.

    • getMaximumOccurs

      public final int getMaximumOccurs()
      Returns the maximum number of occurrences of the association within its containing entity. The returned value is greater than or equal to the get­Minimum­Occurs() value. If there is no maximum, then this method returns Integer​.MAX_VALUE.
      Returns:
      the maximum number of occurrences of the association within its containing entity, or Integer​.MAX_VALUE if none.

    • newInstance

      public AbstractAssociation newInstance()
      Creates a new association instance of this role.
      Returns:
      a new association instance.
      See Also:

    • hashCode

      public int hashCode()
      Returns a hash code value for this association role.
      Returns:
      the hash code for this type.

    • equals

      public boolean equals(Object obj)
      Compares this association role with the given object for equality.
      Parameters:
      obj - the object to compare with this type.
      Returns:
      true if the given object is equal to this type.

    • toString

      public String toString()
      Returns a string representation of this association role. The returned string is for debugging purpose and may change in any future SIS version.
      Overrides:
      to­String in class Object
      Returns:
      a string representation of this association role for debugging purpose.