Package org.geotools.api.feature

Interface Association

All Superinterfaces:

Property

All Known Implementing Classes:

AssociationImpl

public interface Association
extends Property

Extension of Property to represent an Association, or relationship, between two attributes.

The notion of an "association" is similar to that of an association in UML and is used to model a relationship between entities. Examples of such a relationship could be:

• aggregation: An attribute may contain another attribute
• spatial: A feature is spatial related to another (touches, intersects, etc..)
• temporal: An is a previous version of another attribute in a versioning system

Example

The value of an association is an Attribute. As an example consider the following xml complex type definitions:

   <complexType name="fooType">
     ...
   </complexType>
   <element name="foo" type="fooType"/>

   <complexType name="barType">
     <sequence>
       <element name="intAttribute" type="xs:int"/>
       <element name="stringAttribute" type="xs:string"/>
       <element name="fooAssociation" type="xlink:href"/>
     </sequence>
   </complexType>
   <element name="bar" type="barType"/>
 

In the above, "fooType" is an identifiable type. Now consider the following section of an xml instance document:

   <foo id="someId">
     ...
   </foo>
   ...
   <bar>
     <intAttribute>1</intAttribute>
     <stringAttribute>one</stringAttribute>
     <fooAssociation>someId</fooAssociation>
   </bar>
 

Realizing this as objects with attributes and associations we get:

   ComplexAttribute bar = ...;

   //intAttribute
   Attribute intAttribute = (Attribute) bar.getProperty( "intAttribute" );
   intAttribute.getValue() == 1

   //stringAttribute
   Attribute stringAttribute = (Attribute) bar.getProperty( "stringAttribute" );
   stringAttribute.getValue() == "one"

   //fooAssociation
   Association fooAssociation = (Association) bar.getProperty( "fooAssociation" );
   Attribute foo =  fooAssociation.getValue();
 

Author:

Jody Garnett, Refractions Research, Justin Deoliveira, The Open Planning Project

Method Summary

Modifier and Type	Method	Description
AssociationDescriptor	getDescriptor()	Description of the relationship between two attributes.
AttributeType	getRelatedType()	Returns the type of the associated attribute.
AssociationType	getType()	Type of association represented.
Attribute	getValue()	Override of Property.getValue() which type narrows to Attribute.
void	setValue(Object newValue)	Override of Property.setValue(Object) which specifies that newValue should be an instance of Attribute.

Methods inherited from interface Property

getName, getUserData, hasUserData, isNillable

Method Detail

getDescriptor

AssociationDescriptor getDescriptor()

Description of the relationship between two attributes.

Override of Property.getDescriptor() which type narrows to AssociationDescriptor.

Specified by:

getDescriptor in interface Property

Returns:

AssociationDescriptor used to describe the relationship between two attributes; because two attributes are required the descriptor should not be null.

See Also:

Property.getDescriptor()

getType

AssociationType getType()

Type of association represented.

Override of Property.getType() which type narrows to AssociationType.

Specified by:

getType in interface Property

Returns:

The property type.

See Also:

Property.getType()

getValue

Attribute getValue()

Override of Property.getValue() which type narrows to Attribute.

Specified by:

getValue in interface Property

Returns:

The value of the property.

See Also:

Property.getValue()

setValue

void setValue(Object newValue)
       throws IllegalArgumentException

Override of Property.setValue(Object) which specifies that newValue should be an instance of Attribute.

Specified by:

setValue in interface Property

Parameters:

newValue - The new value of the property.

Throws:

IllegalArgumentException - If newValue is not an attribute.

getRelatedType

AttributeType getRelatedType()

Returns the type of the associated attribute.

This method is a convenience for:

 getType().getRelatedType()
 

Returns:

type of the attribute of the association.