The arrayOffset() method of java.nio.LongBuffer class is used to return the offset within the buffer’s backing array of the first element of the buffer. It means that if this buffer is backed by an array, then buffer position p corresponds to array index p + arrayOffset().
In order to check whether this buffer has a backing array, hasArray() method can be used. It ensures that this buffer has an accessible backing array.
Syntax :
public final Long arrayOffset()
Return Value: This method returns the offset within this buffer’s array of the first element of the buffer.
Exception: This method throws ReadOnlyBufferException if this buffer is backed by an array but is read-only
Below program illustrate the arrayOffset() method.
Program 1:
// Java program to demonstrate// arrayOffset() method import java.nio.*;import java.util.*; public class GFG { public static void main(String[] args) { // Declaring the capacity of the LongBuffer int capacity = 10; // Creating the LongBuffer try { // creating object of Longbuffer // and allocating size capacity LongBuffer ib = LongBuffer.allocate(capacity); // putting the value in Longbuffer ib.put(8); ib.put(2, 9); // prLong the LongBuffer System.out.println("LongBuffer: " + Arrays.toString(ib.array())); // prLong the arrayOffset System.out.println("arrayOffset: " + ib.arrayOffset()); } catch (IllegalArgumentException e) { System.out.println("IllegalArgumentException catched"); } catch (ReadOnlyBufferException e) { System.out.println("Exception throws" + e); } }} |
LongBuffer: [8, 0, 9, 0, 0, 0, 0, 0, 0, 0] arrayOffset: 0
Program 2: To demonstrate ReadOnlyBufferException.
// Java program to demonstrate// arrayOffset() method import java.nio.*;import java.util.*; public class GFG { public static void main(String[] args) { // Declaring the capacity of the LongBuffer int capacity = 10; // Creating the LongBuffer try { // creating object of Longbuffer // and allocating size capacity LongBuffer ib = LongBuffer.allocate(capacity); // putting the value in Longbuffer ib.put(8); ib.put(2, 9); ib.rewind(); // Creating a read-only copy of LongBuffer // using asReadOnlyBuffer() method LongBuffer ib1 = ib.asReadOnlyBuffer(); // prLong the LongBuffer System.out.print("Read only buffer : "); while (ib1.hasRemaining()) System.out.print(ib1.get() + ", "); // next line System.out.println(""); // prLong the arrayOffset System.out.println("\nTry to prLong the array offset" + " of read only buffer"); System.out.println("arrayOffset: " + ib1.arrayOffset()); } catch (IllegalArgumentException e) { System.out.println("Exception throws: " + e); } catch (ReadOnlyBufferException e) { System.out.println("Exception throws: " + e); } }} |
Read only buffer : 8, 0, 9, 0, 0, 0, 0, 0, 0, 0, Try to prLong the array offset of read only buffer Exception throws: java.nio.ReadOnlyBufferException
