Using Java 8 Streams to Filter Data with Multiple Filters and Complex Conditions

Java 8 Streams: Multiple Filters vs. Complex Condition

With the introduction of Java 8 and its new Streams API, many developers have been experimenting with the various filtering capabilities provided. One of the most common operations that can be enabled through a Stream is to filter a collection for records that match certain criteria. This criteria can either be expressed via multiple smaller filters or as one complex condition. In this article, we will discuss which approach is more suitable in different scenarios and the pros and cons of each option.

Multiple Filters Approach

The multiple filters approach is simple and straightforward. For example, let’s say you have a collection of products and you want to filter out all the products that are out of stock and have a price higher than $50. The code for this would look something like this:

products.stream()
      .filter(product -> product.getStock() == 0)
      .filter(product -> product.getPrice() > 50)
      .collect(Collectors.toList());

The benefits of this approach are that it is very readable, easy to understand and each filter can be isolated and worked on separately. However, since it uses multiple filters, there is potential for it to be inefficient since the data has to be traversed multiple times.

Complex Condition Approach

The second approach of using a complex condition is also quite simple. You can create a single filter that takes into consideration the multiple conditions or criteria and evaluates them all at once. For example, for the same example above, you can use the following code:

products.stream()
      .filter(product -> product.getStock() == 0 && product.getPrice() > 50)
      .collect(Collectors.toList());

This approach offers the benefit of having fewer traversals of the data, but can be more difficult to read and debug. It is also more difficult to separate out specific criteria if you need to work on it separately.

Conclusion

In conclusion, it is important to consider the pros and cons of both approaches before deciding which one is more suitable for your project. The multiple filter approach is simpler, easier to read and debug, but may be less efficient. The complex condition approach can be more efficient, but can also be harder to read. Ultimately, you need to consider your requirements and choice the one that best fits your project's needs.