Package org.apache.sis.feature

Class SingletonAttribute<V>

java.lang.Object

org.apache.sis.feature.Property

org.apache.sis.feature.Field<V>

org.apache.sis.feature.AbstractAttribute<V>

org.apache.sis.feature.SingletonAttribute<V>

Type Parameters:

V - the type of the attribute value.

All Implemented Interfaces:

Serializable, Cloneable

final class SingletonAttribute<V>
extends AbstractAttribute<V>
implements Cloneable

An instance of an attribute type containing at most one value. The majority of features types contain attributes restricted to such [0 … 1] cardinality. While MultiValuedAttribute would be suitable to all cases, this SingletonAttribute consumes less memory.

Limitations

• Multi-threading: SingletonAttribute instances are not thread-safe. Synchronization, if needed, shall be done externally by the caller.
• Cloning: this class support shallow cloning only: the attribute is cloned, but not its value.

Since:

0.5

Version:

0.8

See Also:

• DefaultAttributeType

Field Summary

Fields

Modifier and Type	Field	Description
private static final long	serialVersionUID	For cross-version compatibility.
private V	value	The attribute value, or null if none.

Fields inherited from class org.apache.sis.feature.AbstractAttribute

type

Constructor Summary

Constructors

Constructor	Description
SingletonAttribute(DefaultAttributeType<V> type)	Creates a new attribute of the given type initialized to the default value.
SingletonAttribute(DefaultAttributeType<V> type, Object value)	Creates a new attribute of the given type initialized to the given value.

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object obj)	Compares this attribute with the given object for equality.
V	getValue()	Returns the attribute value.
int	hashCode()	Returns a hash code value for this attribute.
void	setValue(V value)	Sets the attribute value.

Methods inherited from class org.apache.sis.feature.AbstractAttribute

characteristics, characteristicsReadOnly, clone, create, create, getName, getType, getValues, quality, setValues, toString

Methods inherited from class org.apache.sis.feature.Field

isDeprecated, isSingleton

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

value

private V value

The attribute value, or null if none.

Constructor Details

SingletonAttribute

public SingletonAttribute(DefaultAttributeType<V> type)

Creates a new attribute of the given type initialized to the default value.

Parameters:

type - information about the attribute (base Java class, domain of values, etc.).

SingletonAttribute

SingletonAttribute(DefaultAttributeType<V> type,
 Object value)

Creates a new attribute of the given type initialized to the given value. Note that a null value may not be the same as the default value.

Parameters:

type - information about the attribute (base Java class, domain of values, etc.).

value - the initial value (may be null).

Method Details

getValue

public V getValue()

Returns the attribute value.

Specified by:

getValue in class AbstractAttribute<V>

Returns:

the attribute value (may be null).

See Also:

• AbstractFeature.getPropertyValue(String)

setValue

public void setValue(V value)

Sets the attribute value.

Specified by:

setValue in class AbstractAttribute<V>

Parameters:

value - the new value.

See Also:

• AbstractFeature.setPropertyValue(String, Object)

hashCode

public int hashCode()

Returns a hash code value for this attribute.

Overrides:

hashCode in class Object

Returns:

a hash code value.

equals

public boolean equals(Object obj)

Compares this attribute with the given object for equality.

Overrides:

equals in class Object

Returns:

true if both objects are equal.