Module org.opengis.geoapi

Package org.opengis.feature

Interface DynamicAttribute<V>

Type Parameters:

V - the type of dynamic attribute values.

All Superinterfaces:

Attribute<V>, Property

public interface DynamicAttribute<V>
extends Attribute<V>

An instance of a DynamicAttributeType containing time-dependent values of an attribute. A dynamic attribute represents the result of ascertaining the value of an attribute of a moving feature that changes over time and/or location. Dynamic attributes contain non-spatial values; time-varying geometric values should be represented by trajectories instead. DynamicAttribute holds four main information:

• A reference to a dynamic attribute type which defines the base Java type and domain of valid values.
• One or more values at given times, which may be singletons ([0 … 1] multiplicity) or multi-valued ([0 … ∞] multiplicity).
• One or more values at no particular time (optional), inherited from the parent Attribute interface.
• Optional characteristics about the attribute.

Values are evaluated at given Temporal positions, which may be calendar dates or Julian days for instances. Even though the value of dynamic attribute depends on the spatiotemporal location, this interface only considers the temporal dependencies of their changes of value. Evaluating at the given temporal position may require interpolation. Interpolation algorithm, if any, is implementation-dependent.

DynamicAttribute can be instantiated by calls to DynamicAttributeType.newInstance().

Since:

3.1

See Also:

• DynamicAttributeType
• Attribute

Method Summary

Modifier and Type	Method	Description
DynamicAttributeType<V>	getType()	Returns information about the dynamic attribute (base Java class, domain of values, etc.).
V	valueAt(Temporal time)	Returns the attribute value at the given time, or null if none.
Collection<V>	valuesAt(Temporal time)	Returns all attribute values at the given time, or an empty collection if none.

Methods inherited from interface org.opengis.feature.Attribute

characteristics, getName, getValue, getValues, setValue, setValues

Method Details

getType

DynamicAttributeType<V> getType()

Returns information about the dynamic attribute (base Java class, domain of values, etc.).

Specified by:

getType in interface Attribute<V>

Returns:

information about the dynamic attribute.

valueAt

V valueAt(Temporal time)
   throws OutOfTemporalDomainException,
MultiValuedPropertyException

Returns the attribute value at the given time, or null if none. This convenience method can be invoked in the common case where the maximum number of dynamic attribute values is restricted to 1 or 0.

Parameters:

time - the date, Julian day or other means to represent a position in time.

Returns:

the attribute value at the given time, or null if none.

Throws:

IllegalArgumentException - if the given time is not a type supported by this implementation.

OutOfTemporalDomainException - if the given time is outside the period of validity.

MultiValuedPropertyException - if this attribute contains more than one value at the given time.

valuesAt

Collection<V> valuesAt(Temporal time)
                throws OutOfTemporalDomainException

Returns all attribute values at the given time, or an empty collection if none. Evaluating at the given temporal position may require interpolation. Interpolation algorithm, if any, is implementation-dependent.

Note for implementers

There is different approaches in the way that collection elements are related to those property values:

• The collection may be a snapshot of property values at the method invocation time.
• The collection may be an unmodifiable view of properties values.
• The collection may be live (changes in the collection are reflected in this attribute, and vis-versa).

This method does not mandate a particular approach. However, implementations should document which policy they choose.

Parameters:

time - the date, Julian day or other means to represent a position in time.

Returns:

the attribute values.

Throws:

IllegalArgumentException - if the given time is not a type supported by this implementation.

OutOfTemporalDomainException - if the given time is outside the period of validity.