Java Mapping for Dictionaries

Here is the definition of our EmployeeMap once more:

dictionary<long, Employee> EmployeeMap;

As for sequences, the Java mapping does not create a separate named type for this definition. Instead, the dictionary is simply an instance of the generic type java.util.Map<K, V>, where K is the mapping of the key type and V is the mapping of the value type. In the example above, EmployeeMap is mapped to the Java type java.util.Map<Long, Employee>. The following code demonstrates how to allocate and use an instance of EmployeeMap:

java.util.Map<Long, Employee> em = new java.util.HashMap<Long, Employee>();

Employee e = new Employee();
e.number = 31;
e.firstName = "James";
e.lastName = "Gosling";

em.put(e.number, e);

The type-safe nature of the mapping makes iterating over the dictionary quite convenient:

em.forEach((num, employee) ->
        System.out.println(employee.firstName + " was employee #" + num);

Alternate mappings for dictionary types are also possible.

See Also