Java ShortBuffer allocate()方法及示例

java.nio.ShortBuffer 类的 allocate() 方法用于分配一个新的短缓冲区。
新缓冲区的位置将是零，它的极限是它的容量，尽管标记是未定义的，而且它的每个元素都被初始化为零。它将有一个支持数组，数组的偏移量为零。
语法 ：

public static ShortBuffer allocate(int capacity)

参数 ：该方法接受一个强制性参数 capacity ，该参数指定了新缓冲区的容量，单位为shorts。
返回值 ：该方法返回新的 ShortBuffer。
异常 ：该方法抛出 IllegalArgumentException ，如果容量是一个负整数。
以下程序说明了 allocate( 方法的使用：
程序1：

// Java program to demonstrate
// allocate() method
 
import java.nio.*;
import java.util.*;
 
public class GFG {
    public static void main(String[] args)
    {
 
        // Declaring the capacity of the ShortBuffer
        int capacity = 5;
 
        // Creating the ShortBuffer
 
        // creating object of Shortbuffer
        // and allocating size capacity
        ShortBuffer sb = ShortBuffer.allocate(capacity);
 
        // putting the value in Shortbuffer
        sb.put((short)10000);
        sb.put((short)10640);
        sb.put((short)10189);
        sb.put((short)-2000);
        sb.put((short)-16780);
 
        // Printing the ShortBuffer
        System.out.println("ShortBuffer: "
                           + Arrays.toString(sb.array()));
    }
}

输出

ShortBuffer: [10000, 10640, 10189, -2000, -16780]

程序2： 要显示NullPointerException

// Java program to demonstrate
// allocate() method
 
import java.nio.*;
import java.util.*;
 
public class GFG {
    public static void main(String[] args)
    {
 
        // Declaring the capacity of the ShortBuffer
        // by negative integer
        int capacity = -10;
 
        // Creating the ShortBuffer
        try {
 
            // creating object of shortbuffer
            // and allocating size with negative integer
            System.out.println("Trying to allocate a negative integer");
 
            FloatBuffer fb = FloatBuffer.allocate(capacity);
        }
        catch (IllegalArgumentException e) {
            System.out.println("Exception thrown: " + e);
        }
    }
}

输出

Trying to allocate a negative integer
Exception thrown: java.lang.IllegalArgumentException: capacity < 0: (-10 < 0)

**参考资料: ** https://docs.oracle.com/javase/7/docs/api/java/nio/ShortBuffer.html#allocate()