What is the use of CharArrayReader and StringReader?

Question

I understand the other Reader subclasses in java.io, but I can't think of a use case where I'd need a CharArrayReader or a StringReader when I already have data available as String or char[].

Is it because of compatibility? To "feed" a String or char[] into something that expects Reader as parameter?

score 3 · Accepted Answer · answered Sep 19 '15 at 06:54

3

I would not call it compatibility, it's flexibility.

You are right, some libraries that deal with character based data provide a method accepting a Reader. So the user of that library can choose any mechanism to feed that library.

If you have a file on the harddisk, use a FileReader. If you have an arbitrary InputStream, use an InputStreamReader (with an appropriate encoding). If you already have a simple String in your code, use a StringReader. And so on ...

answered Sep 19 '15 at 06:54

Seelenvirtuose

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I wouldn't call it *flexibility* so much as *abstraction* (which is closely tied with *encapsulation*). – user2864740 Sep 19 '15 at 07:07

score 1 · Answer 2 · answered Sep 19 '15 at 07:27

1

In addition to what has been answered already, these classes are very handy when you write unit tests for a method that expects a reader.

answered Sep 19 '15 at 07:27

Henry

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What is the use of CharArrayReader and StringReader?

2 Answers2