Google Collections中的延迟不可修改的清单 [英] Lazy non-modifiable list in Google Collections
问题描述
我在寻找一个像样的实现一个通用的惰性不可修改的列表实现，以包装我的搜索结果条目。任务的不可修改部分很容易，因为它可以通过 Collections.unmodifiableList（）实现，所以我只需要整理懒惰的部分。
I was looking for a decent implementation of a generic lazy non-modifiable list implementation to wrap my search result entries. The unmodifiable part of the task is easy as it can be achieved by Collections.unmodifiableList() so I only need to sort out the the lazy part.
令人惊讶的是， google集合有什么要提供;而来自Apache Commons Collections的LazyList < a>不支持泛型。
Surprisingly, google-collections doesn't have anything to offer; while LazyList from Apache Commons Collections does not support generics.
I have found an attempt to build something on top of google-collections but it seems to be incomplete (e.g. does not support size()), outdated (does not compile with 1.0 final) and requiring some external classes, but could be used as a good starting point to build my own class.
有人知道任何好的LazyList实现吗？如果没有，你认为哪个选项更好：
Is anybody aware of any good implementation of a LazyList? If not, which option do you think is better:
- 编写我自己的实现，基于google集合的ForwardingList，
- 在Commons Collections LazyList中编写自己的包装器（包装器只会添加泛型，所以我不必在所有地方，只在包装器本身）;
- 只需在
顶部写入一些东西;
- write my own implementation, based on google-collections ForwardingList, similar to what Peter Maas did;
- write my own wrapper around Commons Collections LazyList (the wrapper would only add generics so I don't have to cast everywhere but only in the wrapper itself);
- just write something on top of
java.util.AbstractList;
欢迎任何其他建议。
编辑：解释为什么我需要一个惰性列表。
explanation why I need a lazy list.
我有一个Lucene搜索结果（TopDocs），这基本上是一堆指针Lucene文档。我的搜索结果类将接受这些指针作为输入，并返回由提取和其他处理的Lucene文档组成的对象列表。通过将所有东西包装到一个惰性列表中，我想确保我不必在不必要的时候进行昂贵的处理。
I have got a Lucene search result (TopDocs) which is basically a bunch of pointers to Lucene documents. My search result class would take these pointers as an input and return a list of objects which are made of extracted and otherwise processed Lucene documents. By wrapping everything into a lazy list I want to ensure I am not doing expensive processing when unnecessary.
推荐答案
以不同的方式。而不是经历懒惰和不可修改，我只是实现 java.lang.Iterable< T> 。实施在 remove（）上引发 UnsupportedOperationException 。
I have actually solved this in a different way. Instead of going through lazy and unmodifiable, I simply implemented java.lang.Iterable<T>. The implementation throws UnsupportedOperationException on remove().
我不得不稍微修改一些其他代码部分，放弃一些东西，但我相信这是最好的选择。 Iterable 允许它放在foreach循环。
I had to slightly modify some other code parts, give up something, but I believe this was the best choice. Iterable allows it to be put on foreach loop.
对不起，如果这不是一个可行的选择对于某人在类似的情况，非常感谢的想法。
Sorry to disappoint if this won't be a viable choice for somebody in a similar situation and thanks very much for the ideas.
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