Lookup Map

Simplest Example

As we can see in the example, lookup maps are really two trick ponies:

put -- put an object into the lookup map at a specific key
get -- lookup an object from the lookup map at a specific key

private void demo1()  {
	Map<String, String> map = new HashMap<>();
	map.put("MN", "Minnesota");
	map.put("WI", "Wisconsin");
	map.put("NY", "New York");
	map.put("WA", "Washington");
	String key, name;
	key = "WI";
	name = map.get("WI");
	System.out.printf("Abbrev is %s, name is %s%n", key, name);
}

Lookup Map Using Proper Objects

In the previous example we looked up String values. In reality we'll look up a real objects like a Student, House, City, etc.

Here is an example of a student lookup.

String is the type of the key
Student is the type of the element we lookup in the map (referred to as the value)
Put the Student object into the map at the key
Get the Student object from the map for the given key



private void demoStudentLookup()  {


	List<Student> students = getAllStudents();


	Map<#1String, #2Student> map = new HashMap<>();


	for (Student eachStudent: students)


		#3map.put(eachStudent.getName(), eachStudent);


	Student student;


	String key = "Foo Johnson";


	student = #4map.get(key);


}