如何将for循环转换为生产者? [英] How to convert a for-loop into a producer?

问题描述

有一个 SynchronousProducer 接口，它支持两种操作:

There is a SynchronousProducer interface, that supports two operations:

public interface SynchronousProducer<ITEM> {
    /**
     * Produces the next item.
     *
     * @return produced item
     */
    ITEM next();

    /**
     * Tells if there are more items available.
     *
     * @return true if there is more items, false otherwise
     */
    boolean hasNext();
}

消费者询问生产者是否还有更多可用的物品，以及是否没有任何物品进入关闭顺序.

Consumer asks the producer if there are more items available and if none goes into a shutdown sequence.

现在解决此问题.

此刻，有一个 for循环循环充当生产者:

At the moment there is a for-loop cycle that acts as a producer:

for (ITEM item: items) {
  consumer.consume(item);
}

任务是将控制代码转换为以下代码:

The task is to convert a controlling code into the following:

while (producer.hasNext()) {
  consumer.consume(producer.next())
}

consumer.shutdown();

问题.给出了项:如何编写实现 SynchronousProducer 接口的生产者并复制上面显示的for循环逻辑?

The question. Given the items: how to write the producer implementing SynchronousProducer interface and duplicating the logic of the for-loop shown above?

推荐答案

如果 items 实现了 Iterable ，则可以像下面这样将其适应SynchronousProducer接口:

If items implements Iterable, you can adapt it to your SynchronousProducer interface like this:

class IterableProducer<T> implements SynchronousProducer<T> {

    private Iterator<T> iterator;

    public IterableProducer(Iterable<T> iterable) {
        iterator = iterable.iterator();
    }

    @Override
    public T next() {
        return iterator.next();
    }

    @Override
    public boolean hasNext() {
        return iterator.hasNext();
    }
}

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