Simple Bowling Secretary

The Adapter Pattern converts the interface of a class into another interface the client expects. Adapter lets classes work together that couldn't otherwise because of incompatible interfaces.

An example of the Adapter Design Pattern follows:

public class EnumerationIterator implements Iterator {
	Enumeration enum;
	
	public EnumerationIterator(Enumeration enum) {
		this.enum = enum;
	}
	
	public boolean hasNext() {
		return enum.hasMoreElements();
	}
	
	public Object next() {
		return enum.nextElement();
	}
	
	public void remove() {
		//  NOT Supported by Enumeration
		throw new UnsupportedOperationException();
	}
}

public class AdapterTest {
	//  Vector class now supports iterators, but still has the
	//  elements() method which returns an Enumeration
	public static void main(String[] args) {
		Vector vector = new Vector();
		EnumerationIterator ei;
		vector.add("Bill");  vector.add("Sam");  vector.add("Frodo");
		ei = new EnumerationIterator(vector.elements());
		while (ei.hasNext()) {
			System.out.println(ei.next());
		}
	}
}

Design Patterns

Adapter Pattern

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