Constructors

The @BeanConstructor annotation is used to declare constructors as valid.

Because constructors initialize new objects, they cannot be considered as pure functions. The @BeanConstructor annotation allows you to declare constructors as valid so that they can be used in business rules and decision tables.

A constructor annotated with @BeanConstructor should meet the following requirements:

It should only initialize attribute values of the class.
The names of its parameters should match the names of some of the class attributes. It does not need to initialize all attributes.
A default constructor, which is one without parameters, can also be annotated with @BeanConstructor.

A constructor annotated with @BeanConstructor should preserve the relationship between parameter names and attribute names. Attribute naming follows the JavaBeans conventions for component properties.

By default, the Java™ compiler erases parameter names. To retain them, you can use one of the following options:

Compile with the -parameters option.
Annotate the constructor with @ConstructorAnnotations.
Annotate each parameter with @BusinessName.

The following example shows a @BeanConstructor that creates a new object Borrower and initializes its attribute values:

    @BeanConstructor
    public Borrower(String firstName,
                    String lastName,
                    Borrower spouse,
                    long yearlyIncome,
                    RiskLevel risk,
                    ZonedDateTime birthTime,
                    Address address) {
        this.firstName = firstName;
        this.lastName = lastName;
        this.yearlyIncome = yearlyIncome;
        this.spouse = spouse;
        this.risk = risk;
        this.birthTime = birthTime;
        this.address = address;
    }