Convert single char in String to lower case

Question

I like to 'guess' attribute names from getter methods. So 'getSomeAttribute' shall be converted to 'someAttribute'.

Usually I do something like

String attributeName = Character.toLowerCase(methodName.indexOf(3)) 
                       + methodName.substring(4);

Pretty ugly, right? I usually hide it in a method, but does anybody know a better solution?

Answer 1

The uncapitalize method of Commons Lang shall help you, but I don't think your solution is so crude.

Answer 2

Have a look at the JavaBeans API:

BeanInfo info = Introspector.getBeanInfo(bean
       .getClass(), Object.class);
for (PropertyDescriptor propertyDesc : info
       .getPropertyDescriptors()) {
  String name = propertyDesc.getName();
}

Also see decapitalize.

Answer 3

uncapitalize from commons lang would do it:

String attributeName = StringUtils.uncapitalize(methodName.substring(3));

I need commons lang a lot, but if you don't like that extra jar, you could copy the method. As you can see in it, they doin' it like you:

public static String uncapitalize(String str) {
    int strLen;
    if (str == null || (strLen = str.length()) == 0) {
        return str;
    }
    return new StringBuffer(strLen)
        .append(Character.toLowerCase(str.charAt(0)))
        .append(str.substring(1))
        .toString();
}

Answer 4

Its worth remembering that;

• not all getXXX methods are getters e.g. double getSqrt(double x), void getup().
• methods which return boolean, start with is and don't take an argument can be a getter, e.g. boolean isActive().

Answer 5

Given a character buffer, you can apply the below code:

int i = 0;
for(char x : buffer) {
    buffer[i] = Character.toLowerCase(x);
    i++;
}

Tested and functions :)