DoubleBuffer allocate() method in Java With Examples

The java.nio.DoubleBuffer has an allocate() function. A new double buffer is allocated adjacent to the current buffer using the DoubleBuffer Class. The position of the new buffer will be zero. Its capacity will be its limit. It will have an ambiguous mark. Its elements will all have their initial values set to zero. Its array offset will be 0, and it will have a backup array.

Syntax:

Parameter: The capacity of the new buffer, expressed in double, is a parameter for this method.

Return Value: The new double buffer is returned by this method.

Exception: If the capacity is an integer that is negative, this function throws the IllegalArgumentException.

Example 1:

The code shows how to create and use a DoubleBuffer in Java. The DoubleBuffer is initially given a capacity of 10, then DoubleBuffer.allocate(cap) is then used to allocate this buffer. Using the put(double value) and put(int index, double value) methods, the code inserts values into the buffer at predetermined positions. In the end, it uses Arrays.toString(doublebuff.array()) to print the buffer's contents, displaying the whole array-including the default values (0.0) for unassigned spots. Basic Java buffer allocation, value insertion, and content retrieval are demonstrated in the following example.

Implementation:

FileName: BufferAllocateExample1.java

Output:

 The DoubleBuffer is given by: [9.670000076293945, 0.0, 0.0, 0.0, 8.359999656677246, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0] 

Example 2:

The code demonstrates how to handle an exception that arises while trying to allocate a DoubleBuffer that has less capacity than zero. Initially, it attempts to declare a buffer with a negative capacity (int cap = -12). The improper operation causes an IllegalArgumentException to be thrown during the allocation attempt (DoubleBuffer.allocate(cap)), which is then handled by the catch block. An error message is printed in order to appropriately manage the exception. The example demonstrates error handling when using erroneous arguments in Java's NIO buffer operations (e.g., a negative buffer size).

Implementation:

FileName: BufferAllocateExample2.java

Output:

 Trying to allocate a negative integer The Exception thrown is: java.lang.IllegalArgumentException: capacity < 0: (-12 < 0)