Unmodifiable Map Sample

UnmodifiableMapSample.java

/**
 *
 * @author Michael Hoffer <info@michaelhoffer.de>
 */
public class UnmodifiableMapSample {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // TODO code application logic here
        
        TestClass t1 = new TestClass();
        
        System.out.println("Map:\n" + t1.toString());
        System.out.println("Trying to modify map:");
        
        t1.getReadOnlyMap().put("D", "ValueD");
        
    }

    static class TestClass {

        private Map<String, String> map = new HashMap<String, String>();

        public TestClass() {
            map.put("A", "ValueA");
            map.put("B", "ValueB");
            map.put("C", "ValueC");
        }
        
        @Override
        public String toString() {
            String result = super.toString() + ":\n";
            
            for(String key : map.keySet()) {
                result += "Key:" + key + " = Value:" + map.get(key) + "\n";
            }
            
            return result;
        }
        

        public Map<String, String> getReadOnlyMap() {
            return Collections.unmodifiableMap(map);
        }
    }
}