Module org.opengis.geoapi

Package org.opengis.parameter

Interface ParameterDescriptor<T>

Type Parameters:

T - the type of parameter values.

All Superinterfaces:

GeneralParameterDescriptor, IdentifiedObject

@UML(identifier="OperationParameter",
     specification=ISO_19111)
public interface ParameterDescriptor<T>
extends GeneralParameterDescriptor

The definition of a parameter used by an operation method. Most parameter values are numeric, but other types of parameter values are possible. A parameter descriptor contains the following properties:

• The parameter name.
• The class of values. This is usually Double, double[], Integer, int[], Boolean, String or URI.
• Whether this parameter is optional or mandatory. This is specified by the minimum occurrences number, which can be 0 or 1 respectively.
• The default value and its unit of measurement.
• The domain of values, as a minimum value, maximum value or an enumeration of valid values.

Since:

2.0

See Also:

• ParameterValue
• ParameterDescriptorGroup

Departure from OGC/ISO standard in the name

GeoAPI uses a name which contains the "Descriptor" word for consistency with other libraries in Java (e.g. ParameterListDescriptor in Java Advanced Imaging).

Field Summary

Fields inherited from interface org.opengis.referencing.IdentifiedObject

ALIAS_KEY, DOMAINS_KEY, IDENTIFIERS_KEY, NAME_KEY, REMARKS_KEY

Method Summary

Modifier and Type	Method	Description
ParameterValue<T>	createValue()	Creates a new instance of parameter value initialized with the default value.
default T	getDefaultValue()	Returns the default value for the parameter.
default Comparable<T>	getMaximumValue()	Returns the maximum parameter value.
default Comparable<T>	getMinimumValue()	Returns the minimum parameter value.
default javax.measure.Unit<?>	getUnit()	Returns the unit of measurement for the minimum, maximum and default values.
default Set<T>	getValidValues()	Returns the set of allowed values when these are restricted to some finite set or returns null otherwise.
Class<T>	getValueClass()	Returns the class that describes the type of parameter values.
TypeName	getValueType()	Returns the name that describes the type of parameter values.

Methods inherited from interface org.opengis.parameter.GeneralParameterDescriptor

getDescription, getDirection, getMaximumOccurs, getMinimumOccurs, getName

Methods inherited from interface org.opengis.referencing.IdentifiedObject

getAlias, getDomains, getIdentifiers, getRemarks, toWKT

Method Details

getValueType

@UML(identifier="DQM_Parameter.valueType",
     obligation=MANDATORY,
     specification=ISO_19157)
TypeName getValueType()

Returns the name that describes the type of parameter values. This is closely related to the Class returned by getValueClass():

• If the value class is a collection (e.g. List or array), then this method returns the type of elements in the collection.
• Otherwise this method returns the value class using the mapping documented in TypeName javadoc or using an implementation-dependent mapping.

TypeName is used for encoding parameters in XML or JSON documents, while getValueClass() is used for programmatic purposes.

Returns:

the type name of value component(s) in this parameter.

Since:

3.1

getValueClass

@UML(identifier="GC_ParameterInfo.type",
     obligation=MANDATORY,
     specification=OGC_01004)
Class<T> getValueClass()

Returns the class that describes the type of parameter values. This is usually (but not restricted to) Boolean, Integer, Double, String or URI when the parameter contains a single value. If the parameter can contain multiple values, then the class may be int[], double[], List, Set or Map.

Returns:

the type of parameter values.

getValidValues

default Set<T> getValidValues()

Returns the set of allowed values when these are restricted to some finite set or returns null otherwise. The returned set usually contains code list or enumeration elements.

Note: it is not necessary to provide this property when all values from the code list or enumeration are allowed.

Returns:

a finite set of valid values (usually from a CodeList), or null if it does not apply or if there is no restriction.

Extension to OGC/ISO standard

This method is not part of ISO specification. It is provided as a complement of information.

getMinimumValue

@UML(identifier="GC_ParameterInfo.minimumValue",
     obligation=OPTIONAL,
     specification=OGC_01004)
default Comparable<T> getMinimumValue()

Returns the minimum parameter value. If there is no minimum value, or if the minimum value is inappropriate for the value class, then this method returns null.

Returns:

the minimum parameter value (often an instance of Double), or null.

See Also:

• getMaximumValue()
• getUnit()

getMaximumValue

@UML(identifier="GC_ParameterInfo.maximumValue",
     obligation=OPTIONAL,
     specification=OGC_01004)
default Comparable<T> getMaximumValue()

Returns the maximum parameter value. If there is no maximum value, or if the maximum value is inappropriate for the value class, then this method returns null.

Returns:

the maximum parameter value (often an instance of Double), or null.

See Also:

• getMinimumValue()
• getUnit()

getDefaultValue

@UML(identifier="GC_ParameterInfo.defaultValue",
     obligation=OPTIONAL,
     specification=OGC_01004)
default T getDefaultValue()

Returns the default value for the parameter. If there is no default value, then this method returns null.

Returns:

the default value, or null in none.

See Also:

• getUnit()

getUnit

default javax.measure.Unit<?> getUnit()

Returns the unit of measurement for the minimum, maximum and default values. This attribute applies only if the value is of numeric type (usually an instance of Double).

Returns:

the unit for numeric value, or null if it does not apply to the value type.

See Also:

• getMinimumValue()
• getMaximumValue()
• getDefaultValue()

Extension to OGC/ISO standard

This method is not part of ISO specification. It is provided as a complement of information.

createValue

ParameterValue<T> createValue()

Creates a new instance of parameter value initialized with the default value. While not a requirement, the parameter value descriptor for the created parameter value will typically be this descriptor instance.

Specified by:

createValue in interface GeneralParameterDescriptor

Returns:

a new parameter value initialized to the default value.

See Also:

• getDefaultValue()

Extension to OGC/ISO standard

This method is not part of the ISO specification. It is provided in GeoAPI as a kind of factory method.