Java Named Parameters

javaNamedParameters.java

// reply to http://worklez.name/blog/2012/07/18/java-named-parameters/

class Request { }
class ManagerProvider { }

class Job {
    Job(ManagerProvider provider, Request request, OutputStream out) { }
}

class JobBuilder {

    public Job build() {

        // check required parameters
        if (request == null) {
            throw new IllegalStateException();
        }

        // values by default
        managerProvider = managerProvider == null ? new ManagerProvider() : managerProvider;

        return new (managerProvider, request, output);
    }

    public JobBuilder request(Request request) {
        this.request = request;
        return this;
    }

    public JobBuilder output(Object output) {
        this.output = output;
        return this;
    }

    public JobBuilder managerProvider(ManagerProvider managerProvider) {
        this.managerProvider = managerProvider;
        return this;
    }

    public static void main(String[] args) {
        Job job = new JobBuilder()
            .request(new Request())
            .output(new OutputStream())
            .build();

        // ...
    }

    private Request request;
    private Object output;
    private ManagerProvider managerProvider;
}