@Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null) {
            return false;
        }
        if (getClass() != obj.getClass()) {
            return false;
        }
        Word word = (Word) obj;
        if ((value == null) ? (word.value != null) : !value.equals(word.value)) {
            return false;
        }
        return true;
    }