Java 中的 LongBuffer wrap()方法

原文:https://www . geesforgeks . org/longbuffer-wrap-method-in-Java/

换行(长[]数组)

类的 wrap() 方法用来包装一个 Long 数组,Longo,一个缓冲区。新的缓冲区将由给定的长数组支持;也就是说,对缓冲区的修改将导致数组被修改,反之亦然。新缓冲区的容量和限制将为 array.length,其位置将为零,其标记将未定义。它的后备数组将是给定的数组,并且它的数组偏移量将为零。

语法:

public static LongBuffer wrap(Long[] array)

参数:该方法以数组(将备份该缓冲区的数组)为参数。

返回值:该方法返回新的 Long 缓冲区。

以下程序说明了包裹()的方法:

程序 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

换行(长[]数组,长偏移量,长长度)

新的缓冲区将由给定的长数组支持;也就是说,对缓冲区的修改将导致数组被修改,反之亦然。新缓冲区的容量将是 array.length,它的位置将被偏移,它的限制将是 offset + length,它的标记将是未定义的。它的后备数组将是给定的数组,并且它的数组偏移量将为零。

语法:

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

参数:该方法取以下参数:

  • 数组:将支持新缓冲区的数组。
  • 偏移量:要使用的子阵列的偏移量;必须为非负且不大于数组长度。新缓冲区的位置将被设置为该值。
  • 长度:要使用的子阵列的长度;必须为非负且不大于 array . length–offset。新缓冲区的限制将设置为偏移量+长度。

返回值:这个方法返回新的浮点缓冲区。

抛出:此方法抛出指数超出边界异常(如果偏移和长度参数的前提条件不成立)。

下面的程序说明了 wrap()方法:

程序 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

程序 2: 演示空值异常。

// 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