Package org.apache.sis.parameter

Class UnmodifiableParameterValue<T>

java.lang.Object

org.apache.sis.io.wkt.FormattableObject

org.apache.sis.parameter.DefaultParameterValue<T>

org.apache.sis.parameter.UnmodifiableParameterValue<T>

Type Parameters:

T - the type of the value stored in this parameter.

All Implemented Interfaces:

Serializable, Cloneable, LenientComparable, org.opengis.parameter.GeneralParameterValue, org.opengis.parameter.ParameterValue<T>

final class UnmodifiableParameterValue<T>
extends DefaultParameterValue<T>

A parameter value which cannot be modified. This implementation shall be used only with:

• immutable descriptor,
• immutable or null unit, and
• immutable or cloneable parameter value.

If the parameter value implements the Cloneable interface and has a public clone() method, then that value will be cloned every time the getValue() method is invoked. The value is not cloned by this method however; it is caller's responsibility to not modify the value of the given parameter instance after this method call.

Instances sharing

If the create(ParameterValue) method is invoked more than once with equal descriptor, value and unit, then the method will return the same UnmodifiableParameterValue instance on a best effort basis.

Rational: the same parameter value is often used in many different coordinate operations. For example, all Universal Transverse Mercator (UTM) projections use the same scale factor (0.9996) and false easting (500000 metres).

Since:

0.6

Version:

1.3

Field Summary

Fields

Modifier and Type	Field	Description
private static final WeakHashSet<UnmodifiableParameterValue>	POOL	Pool of parameter instances created in this running JVM.
private static final long	serialVersionUID	For cross-version compatibility.

Fields inherited from class org.apache.sis.parameter.DefaultParameterValue

unit, value

Constructor Summary

Constructors

Modifier	Constructor	Description
private	UnmodifiableParameterValue(org.opengis.parameter.ParameterValue<T> value)	Creates a new parameter with the same value than the given one.

Method Summary

Modifier and Type	Method	Description
DefaultParameterValue<T>	clone()	Returns a modifiable copy of this parameter.
(package private) static <T> UnmodifiableParameterValue<T>	create(org.opengis.parameter.ParameterValue<T> parameter)	Returns an unmodifiable implementation of the given parameter value.
T	getValue()	If the value is cloneable, clones it before to return it.
protected void	setValue(Object value, javax.measure.Unit<?> unit)	Do not allow modification of the parameter value.

Methods inherited from class org.apache.sis.parameter.DefaultParameterValue

booleanValue, doubleValue, doubleValue, doubleValueList, doubleValueList, equals, equals, formatTo, getDescriptor, getUnit, hashCode, intValue, intValueList, setDescriptor, setValue, setValue, setValue, setValue, setValue, setValue, stringValue, unmodifiable, validate, valueFile

Methods inherited from class org.apache.sis.io.wkt.FormattableObject

print, toString, toString, toWKT

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Field Details

serialVersionUID

private static final long serialVersionUID

For cross-version compatibility.

See Also:

• Constant Field Values

POOL

private static final WeakHashSet<UnmodifiableParameterValue> POOL

Pool of parameter instances created in this running JVM. See class javadoc for a rational about why we use a pool.

Constructor Details

UnmodifiableParameterValue

private UnmodifiableParameterValue(org.opengis.parameter.ParameterValue<T> value)

Creates a new parameter with the same value than the given one.

Method Details

create

static <T> UnmodifiableParameterValue<T> create(org.opengis.parameter.ParameterValue<T> parameter)

Returns an unmodifiable implementation of the given parameter value. See class javadoc for more information.

Type Parameters:

T - the type of the value stored in the given parameter.

Parameters:

parameter - the parameter to make unmodifiable, or null.

Returns:

an unmodifiable implementation of the given parameter, or null if the given parameter was null.

getValue

public T getValue()

If the value is cloneable, clones it before to return it.

Specified by:

getValue in interface org.opengis.parameter.ParameterValue<T>

Overrides:

getValue in class DefaultParameterValue<T>

Returns:

the parameter value as an object, or null if no value has been set and there is no default value.

See Also:

• DefaultParameterValue.setValue(Object)
• Parameters.getValue(ParameterDescriptor)

setValue

protected void setValue(Object value,
 javax.measure.Unit<?> unit)

Do not allow modification of the parameter value.

Overrides:

setValue in class DefaultParameterValue<T>

Parameters:

value - the parameter value, or null to restore the default.

unit - the unit associated to the new parameter value, or null.

See Also:

• DefaultParameterValue.validate(Object)

clone

public DefaultParameterValue<T> clone()

Returns a modifiable copy of this parameter.

Specified by:

clone in interface org.opengis.parameter.GeneralParameterValue

Specified by:

clone in interface org.opengis.parameter.ParameterValue<T>

Overrides:

clone in class DefaultParameterValue<T>

See Also:

• DefaultParameterValue(ParameterValue)
• DefaultParameterValue.unmodifiable(ParameterValue)