Java’s PipedInputStream and PipedOutputStream classes allow you to write data to an OutputStream object and to read this data from an InputStream object (see tip “Pass Data Between Threads Using Piped Streams“). The PipedInputStream has these constructors:

 public PipedInputStream () // default constructorpublic PipedInputStream (PipedOutputStream out)  throws IOException

The PipedOutputStream has these constructors:

 public PipedInputStream () // default constructorpublic PipedOutputStream (PipedInputStream in)  throws IOException

The no-argument default constructors for both classes create streams that are not connected to any other stream. The arguments in the other constructors specify the stream that the newly constructed object will connect with. For example, for the PipedInputStream constructor, the resulting object will be connected to the stream “out.” Similarly, for the PipedOutputStream constructor, the resulting object will be connected to the stream “in.”

This code illustrates how to connect the two streams:

 PipedInputStream pins = new PipedInputStream();PipedOutputStream pouts = new PipedOutputStream(pins);

This code achieves the same effect:

 PipedOutputStream pouts = new PipedOutputStream();PipedInputStream pins = new PipedInputStream(pouts);

The two classes also define a connect() method that allows one to connect to the other. For example, if the default constructor is used, objects of the two classes can be connected:

 PipedInputStream pins = new PipedInputStream();PipedOutputStream pouts = new PipedOutputStream();pis.connect(pos);