LongBuffer wrap() method in Java

wrap(Long[] array)

The wrap() method of java.nio.LongBuffer Class is used to wrap a Long array, Longo, a buffer. The new buffer will be backed by the given Long array; that is, modifications to the buffer will cause the array to be modified and vice versa. The new buffer’s capacity and limit will be array.length, its position will be zero, and its mark will be undefined. It’s backing array will be the given array, and its array offset will be zero.

Syntax :

public static LongBuffer wrap(Long[] array)

Parameters: This method takes array(The array that will back this buffer) as a parameter .

Return Value: This method returns the new Long buffer.

Below programs illustrate the wrap() method:

Program 1:

// Java program to demonstrate
// asReadOnlyBuffer() method

import java.nio.*;
import java.util.*;

public class GFG {

    public static void main(String[] args)
    {

        // Declare and initialize the Long array
        long[] ibb = { 1L, 2L, 3L };

        // prLong the Long array length
        System.out.println("Array length : " + ibb.length);

        // prLong the Long array element
        System.out.println("\nArray element : "
                           + Arrays.toString(ibb));

        // wrap the Long array Longo LongBuffer
        // using wrap() method
        LongBuffer longBuffer = LongBuffer.wrap(ibb, 0, ibb.length);

        // Rewind the Longbuffer
        longBuffer.rewind();

        // prLong the Long buffer
        System.out.println("\nlongBuffer : "
                           + Arrays.toString(longBuffer.array()));

        // prLong the LongBuffer capacity
        System.out.println("\nlongbuffer capacity : "
                           + longBuffer.capacity());

        // prLong the LongBuffer position
        System.out.println("\nlongbuffer position: "
                           + longBuffer.position());
    }
}

Output:

Array length : 3

Array element : [1, 2, 3]

LongBuffer : [1, 2, 3]

Longbuffer capacity : 3

Longbuffer position:  0

wrap(Long[] array, Long offset, Long length)

The new buffer will be backed by the given Long array; that is, modifications to the buffer will cause the array to be modified and vice versa. The new buffer’s capacity will be array.length, its position will be offset, its limit will be offset + length, and its mark will be undefined. It’s backing array will be the given array, and its array offset will be zero.

Syntax :

public static LongBuffer wrap (Long[] array, Long offset, Long length)

Parameters: This method takes following parameters:

• array: The array that will back the new buffer.
• offset: The offset of the subarray to be used; must be non-negative and no larger than array.length. The new buffer’s position will be set to this value.
• length: The length of the subarray to be used; must be non-negative and no larger than array.length – offset. The new buffer’s limit will be set to offset + length.

Return Value: This method returns the new float buffer.

Throws: This method throws the IndexOutOfBoundsException(If the preconditions on the offset and length parameters do not hold) .

Below Programs illustrate the wrap() method:

Program 1:

// Java program to demonstrate
// asReadOnlyBuffer() method

import java.nio.*;
import java.util.*;

public class GFG {

    public static void main(String[] args)
    {

        // Declare and initialize the Long array
        long[] ibb = { 1, 2, 3 };

        // prLong the Long array length
        System.out.println("Array length : " + ibb.length);

        // prLong the Long array element
        System.out.println("\nArray element : "
                           + Arrays.toString(ibb));

        // wrap the Long array Longo LongBuffer
        // using wrap() method
        LongBuffer longBuffer = LongBuffer.wrap(ibb, 0,
                                                ibb.length);

        // Rewind the Longbuffer
        longBuffer.rewind();

        // prLong the Long buffer
        System.out.println("\nLongBuffer : "
                           + Arrays.toString(longBuffer.array()));

        // prLong the LongBuffer capacity
        System.out.println("\nLongbuffer capacity : "
                           + longBuffer.capacity());

        // prLong the LongBuffer position
        System.out.println("\nLongbuffer position: "
                           + longBuffer.position());
    }
}

Output:

Array length : 3

Array element : [1, 2, 3]

LongBuffer : [1, 2, 3]

Longbuffer capacity : 3

Longbuffer position:  0

Program 2: To demonstrate NullPoLongerException.

// Java program to demonstrate
// asReadOnlyBuffer() method

import java.nio.*;
import java.util.*;

public class GFG {

    public static void main(String[] args)
    {

        // Declare and initialize the float array
        long[] ibb = { 1, 2, 3 };

        // prLong the Long array length
        System.out.println("Array length : " + ibb.length);

        // prLong the Long array element
        System.out.println("\nArray element : " + Arrays.toString(ibb));

        try {
            // wrap the Long array Longo LongBuffer
            // using wrap() method
            System.out.println("\nHere "
                               + "offset and length does not hold"
                               + " the required condition ");
            LongBuffer longBuffer = LongBuffer.wrap(ibb,
                                                    1,
                                                    ibb.length);

            // Rewind the Longbuffer
            longBuffer.rewind();

            // prLong the Long buffer
            System.out.println("\nLongBuffer : "
                               + Arrays.toString(longBuffer.array()));

            // prLong the LongBuffer capacity
            System.out.println("\nLongbuffer capacity : "
                               + longBuffer.capacity());

            // prLong the LongBuffer position
            System.out.println("\nLongbuffer position:  "
                               + longBuffer.position());
        }
        catch (IndexOutOfBoundsException e) {
            System.out.println("Exception throws:  " + e);
        }
    }
}

Output:

Array length : 3

Array element : [1, 2, 3]

Here offset and length does not hold the required condition 
Exception throws:  java.lang.IndexOutOfBoundsException