import java.util.HashMap;
import java.util.Map;

public enum Operator {
    EQUALS("=="),
    NOT_EQUALS("!="),
    GREATER_EQUALS(">="),
    LESS_EQUALS("<=");
    
    private final String token;
    private static Map<String,Operator> tokenMap;
    
    private Operator(String token){
        this.token = token;
        map(token,this);
    }
    
    private static void map(String token, Operator op){
        if (tokenMap==null) tokenMap = new HashMap<String,Operator>();
        tokenMap.put(token,op);
    }
    
    public static Operator forToken(String token){
        return tokenMap.get(token);
    }
    
    public static void main(String[] args) {
        String[] operators = new String[]{"<=","==","!=",">="};
        for (String opString : operators){
            Operator op = Operator.forToken(opString);
            switch (op) {
                case EQUALS: 
                    System.out.println("equals"); 
                    break;
                case NOT_EQUALS: 
                    System.out.println("not equals"); 
                    break;
                case GREATER_EQUALS: 
                    System.out.println("greater than or equal to"); 
                    break;
                case LESS_EQUALS: 
                    System.out.println("less than or equal to");
                    break;
            }
        }
    }
}