Package org.apache.sis.feature
Class AbstractFeature
- Object
-
- AbstractFeature
-
- All Implemented Interfaces:
Serializable
public abstract class AbstractFeature extends Object implements Serializable
An instance of a feature type containing values for a real-world phenomena. Each feature instance can provide values for the following properties:AbstractFeature
can be instantiated by calls toDefaultFeatureType.newInstance()
.Simple featuresA feature is said “simple” if it complies to the following conditions:- the feature allows only attributes and operations (no associations),
- the cardinality of all attributes is constrained to [1 … 1].
Limitations- Multi-threading:
AbstractFeature
instances are not thread-safe. Synchronization, if needed, shall be done externally by the caller. - Serialization: serialized objects of this class are not guaranteed to be compatible with future versions. Serialization should be used only for short term storage or RMI between applications running the same SIS version.
- Since:
- 0.5
- See Also:
DefaultFeatureType.newInstance()
, Serialized Form
Defined in the
sis-feature
module
-
-
Constructor Summary
Constructors Modifier Constructor Description protected
AbstractFeature(DefaultFeatureType type)
Creates a new feature of the given type.
-
Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description boolean
equals(Object obj)
Compares this feature with the given object for equality.protected Object
getOperationValue(String name)
Executes the parameterless operation of the given name and returns the value of its result.Object
getProperty(String name)
Returns the property (attribute, feature association or operation result) of the given name.abstract Object
getPropertyValue(String name)
Returns the value for the property of the given name.DefaultFeatureType
getType()
Returns information about the feature (name, characteristics, etc.).int
hashCode()
Returns a hash code value for this feature.DataQuality
quality()
Evaluates the quality of this feature at this method invocation time.protected void
setOperationValue(String name, Object value)
Executes the parameterless operation of the given name and sets the value of its result.void
setProperty(Object property)
Sets the property (attribute or feature association).abstract void
setPropertyValue(String name, Object value)
Sets the value for the property of the given name.String
toString()
Formats this feature in a tabular format.
-
-
-
Constructor Detail
-
AbstractFeature
protected AbstractFeature(DefaultFeatureType type)
Creates a new feature of the given type.- Parameters:
type
- information about the feature (name, characteristics, etc.).- See Also:
DefaultFeatureType.newInstance()
-
-
Method Detail
-
getType
public DefaultFeatureType getType()
Returns information about the feature (name, characteristics, etc.).Warning: In a future SIS version, the return type may be changed toorg.opengis.feature.FeatureType
. This change is pending GeoAPI revision.- Returns:
- information about the feature.
-
getProperty
public Object getProperty(String name) throws IllegalArgumentException
Returns the property (attribute, feature association or operation result) of the given name. If the property type is a parameterless operation, then this method may return the result of executing the operation on this feature, at implementation choice.This method returns the property instance. If only the property value is desired, then
getPropertyValue(String)
is preferred since it gives to SIS a chance to avoid the creation ofAbstractAttribute
orAbstractAssociation
instances.Note for subclass implementers: the default implementation returns an instance that redirect all read and write operations togetPropertyValue(String)
andsetPropertyValue(String, Object)
respectively. That default implementation is intended to make easier for developers to create their own customizedAbstractFacture
implementations, but has drawbacks: a newProperty
instance is created every time that thisgetProperty(String)
method is invoked, and the returnedProperty
implementation is not very efficient since it has to perform multiple lookups and type checks. Implementers are encouraged to override this method if they can provide a more efficient implementation. Note that this is already the case when using implementations created byDefaultFeatureType.newInstance()
.Warning: In a future SIS version, the return type may be changed toorg.opengis.feature.Property
. This change is pending GeoAPI revision.- Parameters:
name
- the property name.- Returns:
- the property of the given name (never
null
). - Throws:
IllegalArgumentException
- if the given argument is not a property name of this feature.- See Also:
getPropertyValue(String)
,DefaultFeatureType.getProperty(String)
-
setProperty
public void setProperty(Object property) throws IllegalArgumentException
Sets the property (attribute or feature association). The given property shall comply to the following conditions:- It must be non-null.
- Its name shall be the name of the property to set in this feature.
- Its type shall be the same instance than the property type defined by the feature type for the above name. In other words, the following condition shall hold:
This method is useful for storing non-defaultassert property.getType() == getType().getProperty(property.getName());
Attribute
orFeatureAssociation
implementations in this feature. When default implementations are sufficient, thesetPropertyValue(String, Object)
method is preferred.Note for subclass implementers: the default implementation verifies that the given property has the expected type and a null or empty map of characteristics, then delegates tosetPropertyValue(String, Object)
. That default implementation is intended to make easier for developers to create their own customizedAbstractFacture
implementations, but has drawbacks: the givenProperty
instance is not stored (only its value is stored), and it can not have custom characteristics. Implementers are encouraged to override this method if they can provide a better implementation. Note that this is already the case when using implementations created byDefaultFeatureType.newInstance()
.Warning: In a future SIS version, the argument may be changed toorg.opengis.feature.Property
. This change is pending GeoAPI revision.- Parameters:
property
- the property to set.- Throws:
IllegalArgumentException
- if the name of the given property is not a property name of this feature.IllegalArgumentException
- if the value of the given property is not valid.IllegalArgumentException
- if the property can not be set for another reason.- See Also:
setPropertyValue(String, Object)
-
getPropertyValue
public abstract Object getPropertyValue(String name) throws IllegalArgumentException
Returns the value for the property of the given name. This convenience method is equivalent to invokinggetProperty(String)
for the given name, then to perform one of the following actions depending on the property type and the multiplicity:Class of returned value Property type max. occurs Method invoked Return type AttributeType
0 or 1 Attribute.getValue()
Object
AttributeType
2 or more Attribute.getValues()
Collection<?>
FeatureAssociationRole
0 or 1 FeatureAssociation.getValue()
Feature
FeatureAssociationRole
2 or more FeatureAssociation.getValues()
Collection<Feature>
Note: “max. occurs” is the maximum number of occurrences and does not depend on the actual number of values. If an attribute allows more than one value, then this method will always return a collection for that attribute even if the collection is empty.Multi-valued properties and collectionsIn the case of multi-valued properties (“max. occurs” > 1), the collection returned by this method may or may not be modifiable, at implementation choice. Generally the caller can not add new elements into the returned collection anyway sinceCollection<?>
does not allow such operations, and more specific casts (e.g.Collection<String>
can not be checked at runtime (at least as of Java 8). If a type-safe modifiable collection is desired, the following approach can be used instead:Attribute<String> attribute = Features.cast((Attribute<?>) feature.getProperty(name), String.class); Collection<String> values = attribute.getValues(); // This collection is guaranteed to be "live".
- Parameters:
name
- the property name.- Returns:
- the value for the given property, or
null
if none. - Throws:
IllegalArgumentException
- if the given argument is not an attribute or association name of this feature.- See Also:
AbstractAttribute.getValue()
-
setPropertyValue
public abstract void setPropertyValue(String name, Object value) throws IllegalArgumentException
Sets the value for the property of the given name.ValidationThe amount of validation performed by this method is implementation dependent. Usually, only the most basic constraints are verified. This is so for performance reasons and also because some rules may be temporarily broken while constructing a feature. A more exhaustive verification can be performed by invoking thequality()
method.- Parameters:
name
- the attribute name.value
- the new value for the given attribute (may benull
).- Throws:
IllegalArgumentException
- if the given name is not an attribute or association name of this feature.ClassCastException
- if the value is not assignable to the expected value class.IllegalArgumentException
- if the given value is not valid for a reason other than its type.- See Also:
AbstractAttribute.setValue(Object)
-
getOperationValue
protected Object getOperationValue(String name)
Executes the parameterless operation of the given name and returns the value of its result. This is a convenience method for sub-classes where some properties may be operations that depend on other properties of thisFeature
instance (for example a link to another property value). Invoking this method is equivalent to performing the following steps:Operation operation = (Operation) type.getProperty(name); Property result = operation.apply(this, null); if (result instanceof Attribute<?>) { return ...; // the attribute value. } else if (result instanceof FeatureAssociation) { return ...; // the associated feature. } else { return null; }
- Parameters:
name
- the name of the operation to execute. The caller is responsible to ensure that the property type for that name is an instance ofAbstractOperation
.- Returns:
- the result value of the given operation, or
null
if none. - Since:
- 0.8
-
setOperationValue
protected void setOperationValue(String name, Object value)
Executes the parameterless operation of the given name and sets the value of its result. This method is the complement ofgetOperationValue(String)
for subclasses where some properties may be operations. Not all operations accept assignments, but the link operation for instance does.- Parameters:
name
- the name of the operation to execute. The caller is responsible to ensure that the property type for that name is an instance ofAbstractOperation
.value
- the value to assign to the result of the named operation.- Throws:
IllegalStateException
- if the operation of the given name does not accept assignment.- Since:
- 0.8
-
quality
public DataQuality quality()
Evaluates the quality of this feature at this method invocation time. The data quality reports may include information about whether the property values met the constraints defined by the property types, or any other criterion at implementation choice.The default implementation reports data quality with at least the following information:
-
The scope
level is set to
ScopeCode.FEATURE
. - The reports list contains at most one domain consistency element per property. Implementations are free to omit element for properties having nothing to report.
-
Each report may have one or more conformance result, as documented on
AbstractAttribute.quality()
javadoc.
false
.Example: given a feature with an attribute named “population”. If this attribute is mandatory ([1 … 1] multiplicity) but no value has been assigned to it, then thisquality()
method will return the following data quality report:Data quality ├─Scope │ └─Level………………………………………………… Feature └─Report ├─Measure identification │ └─Code………………………………………… population ├─Evaluation method type…… Direct internal └─Result ├─Explanation……………………… Missing value for “population” property. └─Pass………………………………………… false
- Returns:
- reports on all constraint violations found.
- See Also:
AbstractAttribute.quality()
,AbstractAssociation.quality()
-
The scope
level is set to
-
toString
public String toString()
Formats this feature in a tabular format.- Overrides:
toString
in classObject
- Returns:
- a string representation of this feature in a tabular format.
- See Also:
FeatureFormat
-
hashCode
public int hashCode()
Returns a hash code value for this feature. The default implementation performs the following algorithm:- Iterate over all properties returned by
type.getProperty(true)
– thus including properties inherited from parent types (if any):- For each property type, get the value with
getPropertyValue(String)
. - Compute the hash code from the property name and value, ignoring the properties having a null value.
- For each property type, get the value with
- Iterate over all properties returned by
-
equals
public boolean equals(Object obj)
Compares this feature with the given object for equality. The default implementation performs the following algorithm:- Verify that both objects are non-null and of the same class.
- Iterate over all properties returned by
type.getProperty(true)
– thus including properties inherited from parent types (if any):- For each property type, get the value from both
FeatureType
by a call togetPropertyValue(String)
. - Verify that the two values are either both null, or equal in the sense of
Object.equals(Object)
.
- For each property type, get the value from both
-
-