LongBuffer arrayOffset() method in Java
Last Updated :
19 Sep, 2018
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
// 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);
}
}
}
Output:
LongBuffer: [8, 0, 9, 0, 0, 0, 0, 0, 0, 0]
arrayOffset: 0
Program 2: To demonstrate ReadOnlyBufferException.
Java
// 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);
}
}
}
Output:
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