@XmlElement(value="Filter") public interface Filter
Function
.
Often a filter is used to to define a set feature instances that are to be operated upon. The operating set can be comprised of one or more enumerated features or a set of features defined by specifying spatial and non-spatial constraints on the geometric and scalar properties of a feature type.
Roughly speaking, a filter encodes the information present in the WHERE
clause of a
SQL statement. There are various subclasses of this class that implement many types of filters,
such as simple property comparisons or spatial queries.
The second use of Filter focuses on expressing constraints (or Facets). This use places restrictions on the allowable and is captured as part of schema information (@linkplain FeatureType). This is similar to the XML concept of "facets".
Modifier and Type | Field and Description |
---|---|
static ExcludeFilter |
EXCLUDE
Placeholder Filter that evaulates to
false . |
static IncludeFilter |
INCLUDE
Placeholder Filter that evaulates to
true . |
Modifier and Type | Method and Description |
---|---|
Object |
accept(FilterVisitor visitor,
Object extraData)
Accepts a visitor.
|
boolean |
evaluate(Object object)
Give an object, this method determines if the test(s) represented by this filter object
are passed.
|
static final IncludeFilter INCLUDE
true
.
Filtering a set with Filter.INCLUDE
results in the origional set.
static final ExcludeFilter EXCLUDE
false
.
Filtering a set with Filter.EXCLUDE
results in the empty Set.
boolean evaluate(Object object)
This ability is used to allow Queries against both Features and and non spatial data (such as Record) and to express constraints on permissable data values.
object
- true if the test(s) are passed for the provided object
@Extension Object accept(FilterVisitor visitor, Object extraData)
Implementations of all subinterfaces must have with a method whose content is the following:
return visitor.visit(this, extraData);
Copyright © 1996–2019 Geotools. All rights reserved.