Java LongBuffer compact()用法及代码示例

java.nio.LongBuffer类的compact()方法用于压缩给定的缓冲区。

缓冲区当前位置与其极限之间的值将复制到缓冲区的开头。然后将缓冲区的位置设置为n + 1，并将其限制设置为其容量。缓冲区的位置设置为复制的浮点数。

用法:

public abstract LongBuffer compact()

返回值：此方法返回具有与此缓冲区相同内容的新LongBuffer。

异常：如果此缓冲区是只读的，则此方法引发ReadOnlyBufferException。

以下示例程序旨在说明compact()方法：

范例1：

// Java program to demonstrate 
// compact() 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 
  
        // creating object of Longbuffer 
        // and allocating size capacity 
        LongBuffer ib = LongBuffer.allocate(capacity); 
  
        // putting the value in Longbuffer 
        ib.put(8); 
        ib.put(9); 
        ib.put(9); 
  
        // prLong the LongBuffer 
        System.out.println("Original LongBuffer: "
                           + Arrays.toString(ib.array())); 
  
        System.out.println("Position: " + ib.position()); 
  
        System.out.println("limit: " + ib.limit()); 
  
        // Creating a compacted  LongBuffer of same LongBuffer 
        // using compact() method 
        LongBuffer LongBuffer = ib.compact(); 
  
        // prLong the LongBuffer 
        System.out.println("\nCompacted LongBuffer: "
                           + Arrays.toString(LongBuffer.array())); 
  
        System.out.println("Position: " + LongBuffer.position()); 
  
        System.out.println("limit: " + LongBuffer.limit()); 
  
        // putting the value in compacted Longbuffer 
        LongBuffer.put(9); 
  
        // prLong the LongBuffer 
        System.out.println("\nUpdated Compacted LongBuffer: "
                           + Arrays.toString(LongBuffer.array())); 
        System.out.println("Position: " + LongBuffer.position()); 
        System.out.println("limit: " + LongBuffer.limit()); 
    } 
}

输出：

Original LongBuffer: [8, 9, 9, 0, 0, 0, 0, 0, 0, 0]
Position: 3
limit: 10

Compacted LongBuffer: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
Position: 7
limit: 10

Updated Compacted LongBuffer: [0, 0, 0, 0, 0, 0, 0, 9, 0, 0]
Position: 8
limit: 10

范例2：

// Java program to demonstrate 
// compact() 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(9); 
            ib.put(9); 
            ib.rewind(); 
  
            // Creating a read-only copy of LongBuffer 
            // using asReadOnlyBuffer() method 
            LongBuffer ib1 = ib.asReadOnlyBuffer(); 
  
            // prLong the ReadOnlyBuffer 
            System.out.print("ReadOnlyBuffer LongBuffer: "); 
            while (ib1.hasRemaining()) 
                System.out.print(ib1.get() + ", "); 
            System.out.println(""); 
  
            // prLong the Position of LongBuffer ib 
            System.out.println("\nPosition: " + ib.position()); 
  
            // prLong the Limit of LongBuffer ib 
            System.out.println("\nlimit: " + ib.limit()); 
  
            // Creating a compacted  LongBuffer of same ReadOnlyBuffer 
            // using compact() method 
            System.out.println("\nTrying to compact the ReadOnlyBuffer ib1"); 
            LongBuffer LongBuffer = ib1.compact(); 
        } 
  
        catch (IllegalArgumentException e) { 
            System.out.println("Exception throws " + e); 
        } 
  
        catch (ReadOnlyBufferException e) { 
            System.out.println("Exception throws " + e); 
        } 
    } 
}

输出：

ReadOnlyBuffer LongBuffer: 8, 9, 9, 0, 0, 0, 0, 0, 0, 0, 

Position: 0

limit: 10

Trying to compact the ReadOnlyBuffer ib1
Exception throws java.nio.ReadOnlyBufferException

相关用法

注：本文由纯净天空筛选整理自pawan_asipu大神的英文原创作品 LongBuffer compact() method in Java。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。