sdk/src/com/socialize/oauth/signpost/http/HttpParameters.java
public String getFirst(Object key, boolean percentDecode) {
        SortedSet<String> values = wrappedMap.get(key);
        if (values == null || values.isEmpty()) {
            return null;
        }
        String value = values.first();
        return percentDecode ? OAuth.percentDecode(value) : value;
    }
public String getFirst(Object key, boolean percentDecode) {
        SortedSet<String> values = wrappedMap.get(key);
        if (values == null || values.isEmpty()) {
            return null;
        }
        String value = values.first();
        return percentDecode ? OAuth.percentDecode(value) : value;
    }
Returns the first value from the set of all values for the given
parameter name. If the key passed to this method contains special
characters, you MUST first percent encode it using
{@link OAuth#percentEncode(String)}, otherwise the lookup will fail
(that's because upon storing values in this map, keys get
percent-encoded).

@param key
the parameter name (must be percent encoded if it contains unsafe
characters!)
@param percentDecode
whether the value being retrieved should be percent decoded
@return the first value found for this parameter