Response to Ted Neward’s — Anonymous Generic Methods making things “just work”


Response to Ted Neward’s — Anonymous Generic Methods making things “just work”

I saw Ted Neward’s message and answered the call. I think this is what he wants, but who knows, I don’t really care for C#. But it took 10 minutes in IntelliJ to cook up what I think is the equivalent in Java code.

Update: user57 on codehaus found a cool screencast program, MovieGrab. Here is my screencasting debut (you’ll probably need QT7): neward.mp4 

Here you go Ted. This took me 10 minutes in IntelliJ, I only typed about 10% of it. I think its what you want:

package com.sampullara.neward;

import java.util.List;
import java.util.ArrayList;

public class SetUtils<T> {
public List<T> project(List<T> list, Predicate<T> pred) {
List<T> results = new ArrayList<T>();
for (T t : list) {
if (pred.check(t)) results.add(t);
}
return results;
}
}

package com.sampullara.neward;

public interface Predicate<T> {
public boolean check(T t);
}

package com.sampullara.neward;

public class Person {
private String firstName;
private String lastName;
private int age;

public Person(String firstName, String lastName, int age) {
this.age = age;
this.setFirstName(firstName);
this.setLastName(lastName);
}

public String getFirstName() {
return firstName;
}

public void setFirstName(String firstName) {
this.firstName = firstName;
}

public String getLastName() {
return lastName;
}

public void setLastName(String lastName) {
this.lastName = lastName;
}

public String toString() {
return "Person{" +
"firstName='" + firstName + '\'' +
", lastName='" + lastName + '\'' +
", age=" + age +
'}';
}
}

package com.sampullara.neward;

import java.util.List;
import java.util.ArrayList;

public class Program {
public static void main(String[] args) {
Person cg = new Person("Cathi", "Gero", 35);
Person tn = new Person("Ted", "Neward", 35);
Person sg = new Person("Stephanie", "Gero", 12);
Person mn = new Person("Michael", "Neward", 12);

List<Person> list = new ArrayList<Person>();
list.add(cg);
list.add(tn);
list.add(sg);
list.add(mn);

List<Person> newards =
new SetUtils<Person>().project(list, new Predicate<Person>() {
public boolean check(Person p) { if (p.getLastName().equals("Neward")) return true; else return false; }
});
for (Person p : newards)
System.out.println(p);
}
}
Output: Person{firstName='Ted', lastName='Neward', age=35} Person{firstName='Michael', lastName='Neward', age=12}