Calculation (OpenXava 7.4.1 API)

```
@Retention(RUNTIME)
@Target({FIELD,METHOD})
public @interface Calculation
```
Expression to do the calculation for a property.
Applies to properties.
The expression can contain +, -, *, (), numeric values and properties names of the same entity. For example:
```
  @Calculation("((hours * worker.hourPrice) + tripCost - discount) * vatPercentage / 100") 
  private BigDecimal total;
 
```
You can note as worker.hourPrice can be used to get value from references.
The calculation is executed and displayed when the user changes any value of the properties used in the expression in the UI, however the value is not saved until the user clicks on save button.
Since:

5.7

Author:

Javier Paniza

- Required Element Summary
  
  Required Elements
  Modifier and Type Required Element Description
  
  java.lang.String value
  Expression with +, -, *, (), numeric values and other properties names of the same entity.

- Element Detail
  - value
```
java.lang.String value
```
    Expression with +, -, *, (), numeric values and other properties names of the same entity.