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Object value.
See:
Description
| Interface Summary | |
|---|---|
| Add | Encodes the operation of addition. |
| BinaryExpression | Abstract base class for the various filter expressions that compute some value from two input values. |
| Divide | Encodes the operation of division where the first argument is divided by the second argument. |
| Expression | Abstract super-interface for all the OGC Filter elements that compute values, potentially using feature attributes in the computation. |
| ExpressionVisitor | Visitor with visit methods to be called by Expression.accept(...). |
| Function | Instances of this class represent a function call into some implementation-specific function. |
| Literal | Instances of this interface provide a constant, literal value that can be used in expressions. |
| Multiply | Encodes the operation of multiplication. |
| PropertyName | Expression class whose value is computed by retrieving the value of a feature's property. |
| Subtract | Encodes the operation of subtraction where the second argument is subtracted from the first. |
An expression is a combination of one or more elements that
evaluate to single Object value. The following is adapted from
Filter encoding implementation:
An expression can be formed using the elements:
Add, Subtract,
Multiply, Divide,
PropertyName, Literal
and Function. They all belong to the substitution group
expression which means that any of them can be used wherever an expression is called for. In addition,
the combinaison of these elements are themselves expressions and can be used wherever an expression is
called for.
The elements defined in this package are used to encode the fundamental arithmetic operations of addition, subtraction, multiplication and division. Arithmetic operators are binary operators meaning that they accept two arguments and evaluate to a single result.
A literal value is any part of a statement or expression that is to
be used exactly as it is specified, rather than as a variable or other element. The
Literal element is used to encode literal scalar
and geometric values.
A function is a named procedure that performs a distinct computation.
A function may accept zero or more arguments as input and generates a single result. A
function is composed of the name of the function, encoded using the attribute name, and
zero or more arguments contained within the Function
element. The arguments themselves are expressions.
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