liviutudor

@GET
public Response processRequest( @QueryParam("id")String id, @QueryParam("userId")String userId ) {
  Record retrieve = database.retrieveRecord(id);
  logger.writeEntryFor( id, userId );
  UserProfile profile = userStore.retrieve(userId);
  generateAdResponse(retrieve, profile);
}

liviutudor

public Optional<Double> findExtractAndMax(Collection<Employee> collection, String name) {
    return collection.stream().filter(e -> e.firstName.equals(name)).map(e -> e.salary).max((a, b) -> (int) Math.signum(a - b));
}

//usage
double sal = findExtractAndMax(collection, "Bob");

liviutudor

public Optional<Double> max(Collection<Double> collection) {
    if (collection == null || collection.isEmpty()) return Optional.empty();
    Iterator<Double> iter = collection.iterator();

    Double max = iter.next();
    while (iter.hasNext()) {
        Double n = iter.next();
        if (n > max) max = n;
    }

liviutudor

public Collection<Double> extract(Collection<Employee> collection) {
    return collection.stream().map(c -> c.salary).collect(Collectors.toList());
}

liviutudor

public Collection<Double> extract(Collection<Employee> collection) {
    Collection<Double> list = new ArrayList<>();
    if( collection == null || collection.isEmpty() ) return list;
    for( Employee e : collection ) {
        list.add(e.salary);
    }
    return list;
}

liviutudor

// this returns a list
public Collection<Employee> findName(Collection<Employee> collection, String name) {
    return collection.stream().filter(e -> e.firstName.equals(name)).collect(Collectors.toList());
}

// if we want to return a set (and therefore guarantee uniqueness)
public Collection<Employee> findName(Collection<Employee> collection, String name) {
    return collection.stream().filter(e -> e.firstName.equals(name)).collect(Collectors.toList());
}

liviutudor

public Collection<Employee> findName(Collection<Employee> collection, String name) {
    List<Employee> list = new ArrayList<>();
    if (collection == null || collection.isEmpty()) return list;
    for (Employee e : collection) {
        if (e.firstName.equals(name)) list.add(e);
    }
    return list;
}

// usage

liviutudor

static class Employee {
    String firstName;
    String surname;
    double salary;  //yeah, right!
}

public Optional<Employee> max(Collection<Employee> collection) {
    return collection.stream().max((e1, e2) -> (int) Math.signum(e1.salary - e2.salary));
}

liviutudor

static class Employee {
    String firstName;
    String surname;
    double salary;  //yeah, right!
}

public Optional<Employee> max(Collection<Employee> collection) {
    if (collection == null || collection.isEmpty()) return Optional.empty();
    Iterator<Employee> employeeIterator = collection.iterator();

liviutudor

public Optional<Integer> max(Collection<Integer> collection) {
    return collection.stream().max(Integer::max);
}

// usage
List<Integer> list = ...;
int m = max(list).orElse(0);