CODESAMPLE

Pipes and Filters - Java

Pipes and Filters Java

The Pipes and Filters pattern breaks down a complex processing task into a series of independent, reusable processing steps (filters) connected by channels (pipes) that pass data from one filter to the next. Each filter performs a specific transformation on the data without knowing the source or destination of that data. This promotes modularity, reusability, and simplifies error handling.

The Java code defines Filter interface which each processing stage implements. Concrete filters UpperCaseFilter and RemoveSpacesFilter perform specific string manipulations. A Pipeline class orchestrates the filters, passing the input through each stage sequentially. This design leverages Java’s interfaces and collection pipelines for a clean and extensible solution, aligning with the functional aspects common in modern Java.

import java.util.Arrays;
import java.util.stream.Stream;

interface Filter {
    String process(String input);
}

class UpperCaseFilter implements Filter {
    @Override
    public String process(String input) {
        return input.toUpperCase();
    }
}

class RemoveSpacesFilter implements Filter {
    @Override
    public String process(String input) {
        return input.replaceAll("\\s+", "");
    }
}

class Pipeline {
    private final Stream<Filter> filters;

    public Pipeline(Filter... filters) {
        this.filters = Arrays.stream(filters);
    }

    public String run(String input) {
        return filters.map(filter -> filter.process(input))
                .reduce(input, (acc, filterResult) -> filterResult)
                .orElse(input); // handles empty filter stream
    }
}

public class PipesAndFilters {
    public static void main(String[] args) {
        Pipeline pipeline = new Pipeline(new UpperCaseFilter(), new RemoveSpacesFilter());
        String input = "  Hello world!  ";
        String result = pipeline.run(input);
        System.out.println("Input: " + input);
        System.out.println("Result: " + result);
    }
}