Design Patterns - Proxy

Design Patterns | Proxy

References
Example

References
- Definition: (source: http://en.wikipedia.org/wiki/Proxy_pattern)
  
  A proxy, in its most general form, is a class functioning as an interface to something else.
  The proxy could interface to anything: a network connection, a large object in memory, a file, or some other resource that is expensive or impossible to duplicate.
- Class diagram: (source: http://en.wikipedia.org/wiki/Proxy_pattern)

Example

The Subject:

public interface Logger {
    void log();
}

The Real Subject:

public class FileLogger implements Logger {
    public void log() {
        System.out.println("FileLogger-log");
    }
}

The Proxy:

public class ProxyFileLogger implements Logger {
    private final Logger logger = new FileLogger();

    public void log() {
        logger.log();
    }
}

A simple class to test the Proxy design pattern:

public class ProxyPatternTest {
    public static void main(String[] args) {
        // create the proxy
        Logger logger = new ProxyFileLogger();

        // call method
        logger.log();
    }
}