There are some situations in software development in which we need to improve performance. This is possible with the use of Cache. Imagine a lot of the same objects being created and wasting memory. The Flyweight pattern was created to avoid this...
There are some situations in which we need high flexibility. Let’s consider that we want to create a flexible code for mixing a lot of different pizzas. We would not want to write all the possibilities without a pattern, right? For this...
Composing objects without a pattern can make code really messy – code repetition happens a lot and maintenance is terrible. Fortunately, there is the Composite design pattern that solves this problem completely. Using the Composite pattern we...
When it’s necessary to maintain the state from an object we can create a big code full of ifs controlling the State from the class. Certainly, this is not the right approach to solving this problem. Repetition of code is what we must avoid, we...
Sometimes we need to implement different methods for a POJO with different business requirements. We could certainly create several methods inside the POJO but we would not be utilizing the main benefits of powerful code – cohesion and low...
What if we need to keep many different states of an object? We could keep the information inside objects with a lot of setters and make the code a big mess. This would indeed work but it would be awful to change anything in the future. As we...
What should be done when we need to use a functionality that may be repeated in several classes? Should we repeat the code in all the classes? If the behavior of this functionality changes, you will be obligated to change it in the entire project...
Most of the time we use the Iterator from the Collections API. It’s very important to know how to implement a customized Iterator in order to understand what is happening behind the scenes. If we read Java source code, for example, we are...
Sometimes we have to deal with complex methods where there are many processes and it’s necessary to orchestrate them every time and repeat the code many times. There are other situations in which the methods are very confusing and difficult to...
What if we needed to create logs for all user actions on a project? Imagine if we repeated the same code for everything. The log would probably be like: Header – Always the same Body – Variable Bottom – Always the same Imagine if...