Generics

Last modified Tuesday, 16-Apr-2024 18:54:54 UTC.

Overview
- Generics enable types to be parameters when defining classes, methods, etc.
- The types have to be reference types, not primitive types.
- Example: UseArrayList.java
- Generics provide ...
  - Stronger type checks at compile time
  - Elimination of type casts
  - Enable implementation of generic algorithms
Defining generic methods
- The generic type parameter is provided in angle brackets before the method return type.
- It is necessary to specify the super class of the generic type so that its capabilities are known, e.g., the methods required by an abstract superclass.
- Example: GenericArraySum.java
  - The generic type <E extends Number> says that the generic type E is some kind of Number (see the notes on inheritance).
Defining generic classes
- A generic class is defined with the following format:
```
    class name<T1, T2, ..., Tn> { ... } 
```
- The Ti are the type parameters. By convention, type parameter names are single, uppercase letters.
- Example: GenericPair.java, Gun.java, Cop.java, UseGenericPair.java

Exercises