java.nio.LongBuffer Class in Java

Last Updated : 29 Oct, 2021

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:

Method	Description
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]

LongBuffer equals() method in Java

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