What is Adapter design pattern and it’s advantages
What is Adapter design pattern?
Certainly! The Adapter Pattern is a structural design pattern that allows incompatible interfaces to work together. It acts as a bridge between two incompatible interfaces, making them compatible without changing their existing code.
let’s consider an example where you have a legacy system that uses a socket to connect electronic devices, and you want to introduce a new system that uses an electric base to connect devices. The existing system has a
LegacySocket class with methods that are incompatible with the new
ElectricBase interface. We’ll create an adapter to make the legacy socket compatible with the new interface.
Here’s the Java code:
Let’s consider a basic example where we have an existing
LegacyPrinter class with a method
print(String) and we want to use it in a new system that expects a
Printer interface with methods
scanDocument(). We’ll create an adapter to make these two interfaces compatible.
In this example, the
LegacySocketAdapter class adapts the
LegacySocket to the
ElectricBase interface. The client code interacts with the
ElectricBase interface, and the adapter takes care of translating the method calls to the underlying
LegacySocket implementation. This allows you to introduce the new system with the
ElectricBase interface without modifying the existing
1. Define the Legacy Interface:
2. Create the Legacy Class:
3. Define the Target Interface:
4. Create the Adapter Class:
5. Use the Adapter in the Client Code:
In this example:
LegacyPrinterinterface represents the existing interface that we want to adapt.
OldPrinterclass is the existing class implementing the
Printerinterface is the target interface that our client code expects.
PrinterAdapterclass is the adapter that makes the
LegacyPrintercompatible with the
- In the
AdapterPatternExample, we create an instance of
OldPrinter(the legacy class) and then use the
PrinterAdapterto adapt it to the new
This allows the client code to use the new
Printer interface seamlessly with the existing
LegacyPrinter implementation, thanks to the adapter pattern.
Advantages of adapter design pattern
The Adapter design pattern in Java, as in other programming languages, offers several advantages:
1. Compatibility and Reusability:
- Integration with Existing Code: Adapters allow you to integrate new classes or systems with existing code that has incompatible interfaces. This promotes the reuse of legacy code and avoids unnecessary modifications.
- Interoperability: Adapters enable interoperability between different systems or components with disparate interfaces, fostering compatibility.
2. Minimizes Code Changes: The Adapter pattern helps in minimizing changes to existing code. Instead of modifying the existing code to match new interfaces, you create adapters that mediate between the old and the new.
3. Easy Maintenance: Adapters encapsulate the changes required to make the systems compatible. This encapsulation makes it easier to maintain and modify the adapters without affecting the rest of the codebase.
4. Promotes Separation of Concerns: The Adapter pattern promotes the separation of concerns by isolating the code responsible for adapting the interfaces. This makes the codebase more modular and easier to understand.
5. Facilitates Legacy System Integration: When dealing with legacy systems or third-party libraries, the Adapter pattern is particularly useful. It allows you to integrate new functionality or systems seamlessly without requiring changes to existing, well-established code.
6. Testability: Adapters can simplify the testing process. Since the adapter encapsulates the translation between interfaces, you can easily create test cases for the adapted interfaces without affecting the underlying implementations.
7. Promotes Design Flexibility: The Adapter pattern promotes design flexibility by allowing different implementations to work together. It accommodates changes in requirements without necessitating extensive modifications to the existing codebase.
8. Enhances Code Readability: By using adapters, the code can be more readable and maintainable. Adapters provide a clear separation between the client code and the adapted classes, making it easier to understand the interactions.
9. Facilitates Dependency Inversion: The Adapter pattern adheres to the Dependency Inversion Principle by allowing high-level modules (client code) to depend on abstractions (common interfaces) rather than on specific implementations. This contributes to a more flexible and scalable design.
10. Enables Design Patterns Composition: Adapters can be combined with other design patterns to address complex design scenarios. For example, you might use an Adapter in conjunction with a Composite or Decorator pattern to achieve specific functionality.
In summary, the Adapter design pattern is a valuable tool for achieving interoperability and promoting flexibility in software design. It is particularly useful in scenarios where existing systems or components need to be integrated with new functionality, and their interfaces are initially incompatible.