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java.nio.LongBuffer Class in Java

Last Updated : 29 Oct, 2021
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LongBuffer holds a sequence of long values to be used in an I/O operation. The LongBuffer class provides the following four categories of operations upon long buffers:

  • Absolute and relative get and put methods that read and write single longs.
  • Relative bulk get methods that transfer contiguous sequences of longs from this buffer into an array.
  • Relative bulk put methods that transfer contiguous sequences of longs from a long array or some other long buffer into this buffer.
  • A method for compacting a long buffer.

Long buffers can be created by:

  • allocate() method, which allocates space for the buffer's content,
  • wrap() method, which wraps an existing long array into a buffer, or
  • by creating a view of an existing byte buffer.

Most of the methods of LongBuffer class are directly analogous to the methods defined by ByteBuffer.

Syntax: Class Declaration

public abstract class LongBuffer
extends Buffer
implements Comparable<LongBuffer>

All of the methods of LongBuffer class are listed below as follows:

MethodDescription
allocate​(int capacity)This method allocates a new long buffer.
array​()This method returns the long array that backs this buffer.
arrayOffset​()This method returns the offset within this buffer's backing array of the first element of the buffer.
asReadOnlyBuffer​()This method creates a new, read-only long buffer that shares this buffer's content.
clear​()This method clears this buffer.
compact​()This method compacts this buffer.
compareTo​(LongBuffer that)This method compares this buffer to another.
duplicate​()This method creates a new long buffer that shares this buffer's content.
equals​(Object ob)This method tells whether or not this buffer is equal to another object.
flip​()This method flips this buffer.
get​()This method is a relative get method and returns the long at the buffer's current position.
get​(int index)This method is an absolute get method and returns the long at the given index.
get​(long[] dst)This method is a relative bulk get method and returns this buffer.
get​(long[] dst, int offset, int length)This method is a relative bulk get method and returns this buffer.
hasArray​()This method tells whether this buffer is backed by an accessible long array.
hashCode​()This method returns the current hash code of this buffer.
isDirect​()This method tells whether this long buffer is direct.
limit​(int newLimit)This method sets this buffer's limit.
mark​()This method sets this buffer's mark at its position.
order​()This method retrieves this buffer's byte order.
position​(int newPosition)This method sets this buffer's position.
put​(int index, long l)This method is an absolute put method and returns this buffer.
put​(long l)This method is a relative put method and returns this buffer.
put​(long[] src)This method is a relative bulk put method and returns this buffer.
put​(long[] src, int offset, int length)This method is a relative bulk put method and returns this buffer.
put​(LongBuffer src)This method is a relative bulk put method and returns this buffer.
reset​()This method resets this buffer's position to the previously-marked position.
rewind​()This method rewinds this buffer.
slice​()This method creates a new long buffer whose content is a shared subsequence of this buffer's content.
toString​()This method returns a string summarizing the state of this buffer.
wrap​(long[] array)This method wraps a long array into a buffer.
wrap​(long[] array, int offset, int length)This method wraps a long array into a buffer.

Following are some programs to demonstrate LongBuffer class and its methods:

Example 1:

Java 
// Java program to demonstrate LongBuffer class

// Importing input output classes
import java.nio.*;
// Importing all utility classes
import java.util.*;

// Main Class
public class GFG {

    // Main driver method
    public static void main(String[] args)
    {

        // Declaring and initializing variable to
        // the capacity of the LongBuffer
        int capacity = 5;

        // try block to check for exceptions
        try {

            // creating object of Longbuffer
            // and allocating size capacity
            LongBuffer ib = LongBuffer.allocate(capacity);

            // Adding elements to the objects of Longbuffer
            // class
            // using the pur() method
            ib.put(9);
            ib.put(8);
            ib.put(5);
            ib.rewind();

            // print the original LongBuffer
            // using standard toString() method
            System.out.println(
                "Original LongBuffer: "
                + Arrays.toString(ib.array()));

            // Reads the Long at this buffer's current
            // position using get() method
            Long value = ib.get();

            // Print the Long value
            System.out.println("Long Value: " + value);

            // Reads the Long at this buffer's next position
            // using get() method
            Long value1 = ib.get();

            // Agan, now print the Long value
            System.out.print("Next Long Value: " + value1);
        }

        // Catch blocks to handle the exceptions

        // Catch block 1
        catch (IllegalArgumentException e) {

            // Print the message when there is illegal
            // arguments
            System.out.println(
                "IllegalArgumentException catched");
        }

        // Catch block 2
        catch (ReadOnlyBufferException e) {

            // Print statement when an exception is encountered
            System.out.println(
                "ReadOnlyBufferException catched");
        }

        // Catch block 3
        catch (BufferUnderflowException e) {

            // Print statement when an exception is encountered
            System.out.println("Exception throws: " + e);
        }
    }
}

 
 


Output
Original LongBuffer: [9, 8, 5, 0, 0]
Long Value: 9
Next Long Value: 8


 

Example 2:


 

Java 
// Java program to demonstrate LongBuffer class

// Importing required libraries
import java.nio.*;
import java.util.*;

// Main Class
public class GFG {
    public static void main(String[] args)
    {

        // Declaring and initializing variable to
        // capacity of the LongBuffer
        int Capacity = 10;

        // Creating the LongBuffer

        // creating object of Longbuffer
        // and allocating size capacity
        LongBuffer ib = LongBuffer.allocate(Capacity);

        // Inserting the value in Longbuffer
        // Custom entries
        ib.put(11);
        ib.put(5, 22);

        // Print all the elements inside Longbuffer by
        // use of Arrays.toString() method
        System.out.println("LongBuffer: "
                           + Arrays.toString(ib.array()));
    }
}

 
 


Output
LongBuffer: [11, 0, 0, 0, 0, 22, 0, 0, 0, 0]


 


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