CLASS Verb

Syntax

CLASS accesslevel {STATIC} classname {EXTENDS classname} {IMPLEMENTS interfacelist}

Description

In BBj 6.0 and higher, the CLASS verb marks the beginning of a Custom Object class definition, which must end with a CLASSEND verb.

Parameter	Description
`accesslevel`	The class access level must be specified, and must be either PUBLIC, PRIVATE, or PROTECTED. A PRIVATE class is only visible to code within the same physical file. A PUBLIC class can be accessed from code in other files. A PROTECTED class (BBj 21.0 and higher) can only be accessed from programs within the same directory as the class or interface declaration.
STATIC	The optional STATIC clause indicates that the class or interface definition should be shared between interpreters using the same SSCP. All custom object dependencies of a STATIC class or interface also need to be STATIC. As part of this, static fields of the class will be shared between the interpreters.
`classname`	The class name must begin with a letter or underscore and can contain any combination of letters, numbers and underscores.
EXTENDS `classname`	The optional EXTENDS clause indicates that this class incorporates the methods of another specified Custom Object class. The classname can be: The name of a class whose definition exists in the same program file The name of a class specified in a USE statement in the same program file. A fully qualified class name in the form ::filename::classname .
IMPLEMENTS `interfacelist`	The optional IMPLEMENTS clause indicates that this class implements the method signatures of one or more comma-delimited Custom Object interfaces. Each of these interfaces can be: The name of an interface whose definition exists in the same program file The name of an interface in a USE statement in the same program file. A fully qualified interface name in the form ::filename::interfacename .

Notes

All BBj Custom Object names (interface name, class name, method name, field name) are case-sensitive.

The CLASS verb must be the only statement on the line (with one exception: it can end with a ; REM comment).

The CLASS verb is a syntax error unless the program also contains a CLASSEND verb on a subsequent line.

The CLASS verb may not be nested within any other CLASS, METHOD, or INTERFACE.

The class definition (the area between CLASS and CLASSEND) can contain fields and methods. Any other statements or labels contained within the class definition but not contained within a method definition are unreachable and will not be executed.

A class can implement one or more Interfaces but cannot extend an Interface.

Since STATIC classes or interfaces are shared by multiple interpreters, starting a new interpreter will not allow you to load a new version of the class or interface if it is changed on disk, assuming that the old version was previously successfully loaded. You may need to restart BBjServices in order to get a new version.

Example

rem ' CLASS Verb Example

rem ' Payroll

e1! = new Salaried()
e1!.setID(1)
e1!.setName("Mary Jones")
e1!.setMonthlySalary(5000)
e1!.print()
print "GL Account:",e1!.account()

e2! = new Hourly()
e2!.setID(2)
e2!.setName("John Smith")
e2!.setHourlyRate(15)
e2!.setHoursWorked(168)
e2!.print()
print "GL Account:",e2!.account()

interface public Address
    method public void address()
interfaceend

interface public Pay
    method public void print()
interfaceend

interface public GL
    method public BBjNumber account()
interfaceend

interface public Payable extends Pay, GL
    method public BBjNumber pay()
interfaceend

class public Employee
    field public BBjNumber ID
    field public BBjString Name$
classend

class public Salaried extends Employee implements Payable
    field public BBjNumber MonthlySalary

    method public BBjNumber pay()
        methodret #MonthlySalary
    methodend

    method public void print()
        print "Employee",#getID(),": ",#getName()
        print #pay():"($###,###.00)"
    methodend

    method public BBjNumber account()
        methodret 11111
    methodend

classend

class public Hourly extends Employee implements Payable
    field public BBjNumber HourlyRate
    field public BBjNumber HoursWorked

    method public BBjNumber pay()
        methodret #HourlyRate*#HoursWorked
    methodend

    method public void print()
        print "Employee",#getID(),": ",#getName()
        print #pay():"($###,###.00)"
    methodend

    method public BBjNumber account()
        methodret 22222
    methodend

classend

CLASS Verb

Syntax

Description

Notes

Example

Version History

See Also