Data Structures and Collections - Java 8 Recipes - page 236

public String getFieldName() {
return this.fieldName;
}
abstract boolean validate(String fieldValue);
// Static class members
//
private static final Map<String, FieldType>
nameToFieldTypeMap = new HashMap<>();
static {
for (FieldType field : FieldType.values()) {
nameToFieldTypeMap.put(field.getFieldName(),
field);
}
}
public static FieldType lookup(String fieldName) {
return
nameToFieldTypeMap.get(fieldName.toLowerCase());
}
private static void printValid(FieldType field,
String fieldValue, boolean valid) {
System.out.println(field.getFieldName() +
"(\"" + fieldValue + "\")
valid: " + valid);
}
public static void main(String... args) {
String fieldName = "password";
String fieldValue = "1Cxy9"; // invalid - must
be at least 6 characters
FieldType field = lookup(fieldName);
printValid(field, fieldValue,
field.validate(fieldValue));