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Trail: Essential Java Classes
Lesson: I/O: Reading and Writing (but no 'rithmetic)

## How to Wrap a Stream

> The `reverse` method contains some other interesting code; in particular, these two statements:

> >     BufferedReader in = new BufferedReader(source);
> >     ...
> >     PrintWriter out = new PrintWriter(pipeOut);

> The code opens a `BufferedReader` on `source`, which is another reader of a different type. This essentially "wraps" `source` in a `BufferedReader`. The program reads from the `BufferedReader`, which in turn reads from `source`. The program does this so that it can use `BufferedReader`'s convenient `readLine` method. Similarly, the `PipedWriter` is wrapped in a `PrintWriter` so that the program can use `PrintWriter`'s convenient `println` method. You will often see streams wrapped in this way so as to combine the various features of the many streams.

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