Mastering High Performance with Kotlin

Higher-order functions

Higher-order functions are an extremely powerful way to reuse behavior flexibly. It's easy to implement the strategy pattern using higher-order functions.

Let's recall a good old example with compression that includes the CompressionStrategy interface:

public interface CompressionStrategy {    File compress(File original);}

Here's one implementation of this interface:

public class ZipCompressionStrategy implements CompressionStrategy {    @Override    public File compress(File original) {        throw new NotImplementedException();    }}

And the Archiver class that holds a certain strategy and archives a file:

public class Archiver {    private CompressionStrategy strategy;    public CompressionStrategy getStrategy() {        return strategy;    }