@Override
    public boolean contains(Object key) {
        return indexOf(key) >= 0;
    }
Check whether a value exists in the set.

@param key The value to search for.
@return Returns true if the value exists, else false.
replugin-host-library/replugin-host-lib/src/main/java/com/qihoo360/replugin/utils/basic/ArraySet.java