Java NIO Pipe

A Java NIO Pipe is used for establishing the one-way data connection between two threads. It has a sink channel and source channel. The data is writing to the sink channel and this data can then be read from a source channel.

In Java NIO the package java.nio.channel.pipe is used to read and write the data in a sequence. Pipe is used for ensuring that data must be read in a same order in which it is written to the Pipe.

Let's see the block diagram illustration of Pipe operational principle:

Creating a Pipe

For creating a pipe we need to open a Pipe by calling the Pipe.open() method.

The syntax used for opening or creating a Pipe is:

Reading from a Pipe

For reading the data from a Pipe we need to access the source channel. Therefore the syntax used for accessing the source channel is:

For reading the data from the SourceChannel we call the read() method as given below:

ByteBuffer bb= ByteBuffer.allocate(512);
int bytesRead = inChannel.read(bb);

The integer value return by the read() method is used for determining the number of bytes were read into the buffer.

Writing to a Pipe

For writing the data to a Pipe we need to access the sink channel. Therefore the syntax used for accessing the sink channel is:

For writing the data to a SinkChannel we call the write() method as given below:

String newData = "The new String is writing in a Pipe..." + System.currentTimeMillis();
ByteBuffer bb= ByteBuffer.allocate(512);
bb.clear();
bb.put(newData.getBytes());
bb.flip();
while(bb.hasRemaining()) {
SinkChannel.write(bb);
}

strong>Basic Pipe Example:

package com.javatpoint;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.Pipe;
public class PipeExample {
  public static void main(String[] args) throws IOException {
      //The Pipe is created
      Pipe pipe = Pipe.open();
      //For accessing the pipe sink channel 
      Pipe.SinkChannel skChannel = pipe.sink();
      String td = "Data is successfully sent for checking the java NIO Channel Pipe.";
ByteBuffer bb = ByteBuffer.allocate(512);
      bb.clear();
      bb.put(td.getBytes());
      bb.flip();
       //write the data into a sink channel.
      while(bb.hasRemaining()) {
          skChannel.write(bb);
      }
      //For accessing the pipe source channel
      Pipe.SourceChannel sourceChannel = pipe.source();
      bb = ByteBuffer.allocate(512);
     //The data is write to the console   
      while(sourceChannel.read(bb) > 0){
          bb.flip();
          
          while(bb.hasRemaining()){
              char TestData = (char) bb.get();
              System.out.print(TestData);
          }
          bb.clear();
      }
  }
}

Output:

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