How do I cast from int to generic type Integer?

Posted by Rob Kent on Stack Overflow See other posts from Stack Overflow or by Rob Kent
Published on 2010-04-24T15:53:58Z Indexed on 2010/04/24 16:03 UTC
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I'm relatively new to Java and am used to generics in C# so have struggled a bit with this code. Basically I want a generic method for getting a stored Android preference by key and this code, albeit ugly, works for a Boolean but not an Integer, when it blows up with a ClassCastException. Can anyone tell me why this is wrong and maybe help me improve the whole routine (using wildcards?)?

    public static <T> T getPreference(Class<T> argType, String prefKey, T defaultValue,
        SharedPreferences sharedPreferences) {

    ...

    try {
        if (argType == Boolean.class) {
            Boolean def = (Boolean) defaultValue;
            return argType.cast(sharedPreferences.getBoolean(prefKey, def));
        } else if (argType == Integer.class) {
            Integer def = (Integer) defaultValue;
            return argType.cast(sharedPreferences.getInt(prefKey, def));
        } else {
            AppGlobal.logWarning("getPreference: Unknown type '%s' for preference '%s'. Returning default value.",
                    argType.getName(), prefKey);
            return defaultValue;
        }
    } catch (ClassCastException e) {
        AppGlobal.logError("Cast exception when reading pref %s. Using default value.", prefKey);
        return defaultValue;
    }
}

I've tried various ways - using the native int, casting to an Integer, but nothing works.

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