Identifying objects in legacy systems using design metrics

Many organisations are migrating towards object-oriented technology. Howeve r, owing to the business value of legacy software, new object-oriented deve lopment has to be weighed against salvaging strategies. The incremental mig ration of procedurally oriented systems to object-oriented platforms seems to be a feasible approach, although it must be considered as risky as redev elopment. This approach uses reverse engineering activities to abstract an object-oriented model from legacy code. The paper presents a method for dec omposing legacy systems into objects. The identification of objects is cent red around persistent data stores, such as files or tables in the database, while programs and routines are candidates for implementing the object met hods. Associating the methods to the objects is achieved by optimising sele cted object-oriented design metrics. The rationale behind this choice is th at the object-oriented decomposition of a legacy system should not result i n a poor design, as this would make the re-engineered system more difficult to maintain. (C) 1999 Elsevier Science Inc. All rights reserved.