Manufacturing work cell - Software Development Case Studies in Java - page 229

Table 9.5 The sequence of events generated during the simulation and two GUI screen shots

Broadcaster Event Value Time

NutSource LOADED Nut 809

ScrewSource LOADED Screw 1461

NutSource LOADED Nut 1694

Drill WORKDONE Drill 2309

ScrewSource LOADED Screw 2807

AGV ARRIVED Drill 2959

NutSource LOADED Nut 3181

AGV UNLOADED Drill 3259

Cutter WORKDONE Cutter 3261

Drill WORKDONE Drill 3809

AGV ARRIVED Assembler 3909

Broadcaster Event Value Time

ScrewSource LOADED Screw 4101

NutSource LOADED Nut 4108

AGV LOADED Drill 4209

AGV ARRIVED Cutter 4859

ScrewSource LOADED Screw 4964

Cutter WORKDONE Cutter 5061

NutSource LOADED Nut 5124

AGV UNLOADED Cutter 5159

Drill WORKDONE Drill 5309

AGV ARRIVED Assembler 5809

AGV LOADED Cutter 6109

Copyright © 2005 Sun Microsystems, Inc. All rights reserved.
Reproduced by permission of Sun Microsystems, Inc.

9.6 ■ Extension

A number of functional requirements have not been taken into consider-
ation in Prototype 2. The reader might want to develop a new prototype of
the work cell system that solves the design problems that have not been
addressed so far. Here is a list of possible extensions.

Class Assembler should implement the notification of the events FULL and
NOTFULL to inform the AGV that the input buffer is full or is getting empty.

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Class Assembler should manage two distinct input buffers for nuts and
screws; in fact if we model a single input buffer for both types of piece,
it might happen that the input buffer gets full of nuts (or screws). This
situation causes a deadlock, because the assembler extracts only pairs of
nuts and screws from the input buffer. Thus, if the buffer contains only
pieces of the same type, it will never start getting empty and there will
never be positions available for pieces of the other type.

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