org.opengis.feature
Interface FeatureAttributeDescriptor

public interface FeatureAttributeDescriptor

Descriptor that gives the name, data type, and cardinality of an attribute from a FeatureType.

Author's note: In the OGC Feature abstract model, attributes have both a name and a type. Then the type itself has a name and a datatype. This is apparently done so that attributes of different names, perhaps in different types of Features, can share a type. However, this seems a little confusing. Here, the name of the Feature attribute and its datatype are rolled into one object.

Since:

GeoAPI 2.0

Method Summary

DataType	getDataType() Returns a constant from DataType.
int	getMaximumOccurrences() Returns the maximum number of occurrences of this attribute on a given feature.
int	getMinimumOccurrences() Returns the minimum number of occurrences of this attribute on a given feature.
String	getName() Returns the name of this attribute.
Class	getObjectClass() For attributes of type OBJECT, this returns the Java Class object that class or interface that all values of this attribute can be cast to.
int	getPrecision() For attributes of type DECIMAL, this returns the maximum number of places after the decimal point.
int	getSize() Returns a number that indicates the size of a given attribute.
boolean	isPrimaryKey() Returns true if this attribute forms all or part of the unique identifying value for the feature it is contained by.

Method Detail

getName

String getName()

Returns the name of this attribute. This is the name that can be used to retrieve the value of an attribute and usually maps to either an XML element name or a column name in a relational database.

getDataType

DataType getDataType()

Returns a constant from DataType. The return value of this method indicates how the return values of getSize(), getPrecision(), and getObjectClass() should be interpreted. For attributes whose maximum cardinality is greater than one, this should return the data type of the individual elements of the collection.

getSize

int getSize()

Returns a number that indicates the size of a given attribute. See the documentation for the various constants of DataType for how to interpret this value. As an example, when the data type is STRING, this value indicates the maximum length of the string.

getPrecision

int getPrecision()

For attributes of type DECIMAL, this returns the maximum number of places after the decimal point. For other types, this must always return zero.

getObjectClass

Class getObjectClass()

For attributes of type OBJECT, this returns the Java Class object that class or interface that all values of this attribute can be cast to.

getMinimumOccurrences

int getMinimumOccurrences()

Returns the minimum number of occurrences of this attribute on a given feature. The vast majority of data sources and data consumers will only function with this value being zero or one. If the minimum number of occurrences is zero, this is equivalent, in SQL terms, to the attribute being nillable.

getMaximumOccurrences

int getMaximumOccurrences()

Returns the maximum number of occurrences of this attribute on a given feature. The vast majority of data sources and data consumers will only function with this value being one. A value of Integer.MAX_VALUE indicates that the maximum number of occurrences is unbounded.

isPrimaryKey

boolean isPrimaryKey()

Returns true if this attribute forms all or part of the unique identifying value for the feature it is contained by. The primary key attributes uniquely identify this feature from other features of the same type. This is different from the feature's ID, which must uniquely identify the Feature among all feature types.