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Engenharia de Aplicações (EAPLI)
Polythecnic of Porto, School of Engineering
This application is part of the lab project for the course unit EAPLI. Parts of the application were developed to show specific approaches or techniques; as such, the overall application is not consistent in terms of design. for production ready code this would obvisously be a problem as we should strive for consistency. In this case, it is acceptable as the inconsistencies are meant to provide samples of different valid approaches.
Base logo created with kammerl ascii signature using font "big"
Paulo Gandra de Sousa [email protected] / [email protected]
Copyright (c) 2013-2019 the original author or authors.
MIT License
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
make sure Maven is installed and on the PATH
If using an Oracle database, you will need to change your maven settings for downloading the Oracle drivers. see https://blogs.oracle.com/dev2dev/entry/how_to_get_oracle_jdbc#settings for more information.
run script
rebuild-all.bat
make sure a JRE is installed and on the PATH
run script
run-backoffice
or
run-user.bat
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eapli.base.consoleapp
- presentation using console
- Main class
- application properties in resource folder
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eapli.base.bootstrap
- bootstrap data. should be ignored on a "real" instalation
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eapli.base.core
- use case controllers, model, and persistence
The application follows a typical layered approach
UI -> Controller -+-> Domain
| ^
| |
+-> Repositories
Two different approaches are possible:
- pure domain objects without any knowledge of the persistence
- domain objects that can save and load thenselves from persistence (thus, an Active Record)
In the first case, the controller is responsible for obtaining the domain objects from the repository, asking the domain objects to perform the business logic and then pass them back to the repository. in this case, the domain objects can "easily" be tested as they do not depend on any other package this gets trickier when we need/want to have lazy load of collections...
In the second case, the controller asks the domain object class to load a certain instance, asks that object to perform the business operation and then asks the object to save itself back to the database
The decision is to use domain objects outside of the controllers boundary. One could argue that domain objects should be known only "inside" the application boundary and as such other data structures should be returned to outside layers, i.e., DTO (Data Transfer Objects).
Both approaches have advantages and disavantages:
-
in memory
-
advantages
- allows the use of business logic in code
- disavantages performance may be poor
-
-
at persistence layer
-
advantages
- use of aggregated SQL functions is straigth forward
- performance
-
disavantages
- complicated business logic is hard to implement
-
//TODO provide one example of each approach.
See also http://www.martinfowler.com/articles/dblogic.html
use services at the application or domain layer
it is best if they call application services
Should the rules for the Creator pattern be fully enforced, e.g., the responsibility to create a Payment should be of Expense, or can the controller/UI create a Payment and pass it to the Expense?
Factor out common behaviour in an application service.
When showing movements gruped by type, who performs the sum operation? UI, Controller or Domain object?
the UI might not be smart enough to compute the total sum with enough precision, and would carry a burden for the computer running the interface
the Controller might indeed perform such calculation as it has all the data is needs for a short period of time, but it is not the controller function to perform mathematical operations
the domain object might indeed be the very best resource to calculate the sum for each expense type, but it would not make sense to delegate the domain object to the interface.
this can be another strategy
Start by reading the essential material listed in EAPLI framework
T.B.D.