Patterns for enterprise application integration

The development of Information Technology (IT) demands the integration of systems (legacy or new), so that they can operate in a distributed way and promoting the reuse of design, code and information in a high granularity level. Enterprise Application Integration (EAI) plays a fundamental role in this scenario. It can be conducted by different means, for example, by sharing the access to databases or using Web Services (WS). Both solutions are being adopted by organizations, although they present advantages and disadvantages that should be analysed. Several restrictions can be present in the particular integration scenario, causing problems to be solved before deciding if the integration should be done by data access or WS. So, this work has the objective of documenting these problems and solutions in the pattern format, in order to make available to other developers the knowledge acquired when doing EAI. These solutions can be used to improve reuse in certain integration contexts, depending on the organization business rules.