java - 重构了很多类似方法的代码

Question

嗨，我的代码中有很多类似的方法，如下所示，也许将来我会有更多。

public void getParticularBook(String nameOfBook){
    String bookDetails = "";
    Iterator<Book> iterator = allBooks.iterator();
    while(iterator.hasNext()) {
        Book b = iterator.next();
        if(b.getTitle().equalsIgnoreCase(nameOfBook)){
            bookDetails = b.toString();
        }
    }
    System.out.println(bookDetails);
}

public void getBooksDataOnRange(int from, int to){
    String bookDetails = "";
    Iterator<Book> iterator = allBooks.iterator();
    while(iterator.hasNext()) {
        Book b = iterator.next();
        if(b.getIssueYear() >= from && b.getIssueYear() <= to){
            bookDetails = b.toString();
        }
    }

    if(bookDetails.isEmpty()){
        System.out.println("No books in range of: " + from + "-" + to);
    }
    System.out.println(bookDetails);
}

public void getBooksDataOnType(String type){
    String bookDetails = "";
    Iterator<Book> iterator = allBooks.iterator();
    while(iterator.hasNext()) {
        Book b = iterator.next();
        if(b.getType().equalsIgnoreCase(type)){
            bookDetails = b.toString();
        }
    }

    if(bookDetails.isEmpty()){
        System.out.println("No books of type: " + type);
    }
    System.out.println(bookDetails);
}

以上方法是某种过滤器，它基于例如返回数据书籍类型、书籍发行日期。

问题是，是否可以重构所有此类方法的代码？或者也许更好地遵循上述方案？ 谢谢各位的解答

Answer 1

您可以创建一个名为 getBooksWithPredicate 的方法:

public static void getBooksWithPredicate(Predicate<Book> predicate, String errorMessage) {
    String bookDetails = "";
    Iterator<Book> iterator = allBooks.iterator();
    while(iterator.hasNext()) {
        Book b = iterator.next();
        if(predicate.test(b)){
            bookDetails = b.toString();
        }
    }

    if(bookDetails.isEmpty()){
        System.out.println(errorMessage);
    }
    System.out.println(bookDetails);
}

这基本上是所显示的所有三种方法的概括。然后调用这个方法就可以实现这三个方法:

public void getParticularBook(String nameOfBook){
    getBooksWithPredicate(b -> b.getTitle().equalsIgnoreCase(nameOfBook), "");
}

public void getBooksDataOnRange(int from, int to){
    getBooksWithPredicate(b -> b.getIssueYear() >= from && b.getIssueYear() <= to, "No books in range of: " + from + "-" + to);
}

public void getBooksDataOnType(String type){
    getBooksWithPredicate(b -> b.getType().equalsIgnoreCase(type), "No books of type: " + type);
}