Java IntBuffer compact()用法及代码示例

java.nio.IntBuffer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 IntBuffer compact()

返回值：此方法返回具有与此缓冲区相同内容的新IntBuffer。

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 IntBuffer 
        int capacity = 10; 
  
        // Creating the IntBuffer 
  
        // creating object of Intbuffer 
        // and allocating size capacity 
        IntBuffer ib = IntBuffer.allocate(capacity); 
  
        // putting the value in Intbuffer 
        ib.put(8); 
        ib.put(9); 
        ib.put(9); 
  
        // print the IntBuffer 
        System.out.println("Original IntBuffer: "
                           + Arrays.toString(ib.array())); 
  
        System.out.println("Position: " + ib.position()); 
  
        System.out.println("limit: " + ib.limit()); 
  
        // Creating a compacted  IntBuffer of same IntBuffer 
        // using compact() method 
        IntBuffer IntBuffer = ib.compact(); 
  
        // print the IntBuffer 
        System.out.println("\nCompacted IntBuffer: "
                           + Arrays.toString(IntBuffer.array())); 
  
        System.out.println("Position: " + IntBuffer.position()); 
  
        System.out.println("limit: " + IntBuffer.limit()); 
  
        // putting the value in compacted Intbuffer 
        IntBuffer.put(9); 
  
        // print the IntBuffer 
        System.out.println("\nUpdated Compacted IntBuffer: "
                           + Arrays.toString(IntBuffer.array())); 
        System.out.println("Position: " + IntBuffer.position()); 
        System.out.println("limit: " + IntBuffer.limit()); 
    } 
}

输出：

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

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

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

范例2：演示ReadOnlyBufferException

// 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 IntBuffer 
        int capacity = 10; 
  
        // Creating the IntBuffer 
        try { 
  
            // creating object of IntBuffer 
            // and allocating size capacity 
            IntBuffer ib = IntBuffer.allocate(capacity); 
  
            // putting the value in Intbuffer 
            ib.put(8); 
            ib.put(9); 
            ib.put(9); 
            ib.rewind(); 
  
            // Creating a read-only copy of IntBuffer 
            // using asReadOnlyBuffer() method 
            IntBuffer ib1 = ib.asReadOnlyBuffer(); 
  
            // print the ReadOnlyBuffer 
            System.out.print("ReadOnlyBuffer IntBuffer: "); 
  
            while (ib1.hasRemaining()) 
                System.out.print(ib1.get() + ", "); 
            System.out.println(""); 
  
            // print the Position of IntBuffer ib 
            System.out.println("\nPosition: " + ib.position()); 
  
            // print the Limit of IntBuffer ib 
            System.out.println("\nlimit: " + ib.limit()); 
  
            // Creating a compacted  IntBuffer of same ReadOnlyBuffer 
            // using compact() method 
            System.out.println("\nTrying to compact the ReadOnlyBuffer ib1"); 
  
            IntBuffer IntBuffer = ib1.compact(); 
        } 
  
        catch (IllegalArgumentException e) { 
            System.out.println("Exception throws " + e); 
        } 
  
        catch (ReadOnlyBufferException e) { 
            System.out.println("Exception throws " + e); 
        } 
    } 
}

输出：

ReadOnlyBuffer IntBuffer: 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nitin_sharma大神的英文原创作品 IntBuffer 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。