Java DoubleBuffer asReadOnlyBuffer()用法及代码示例

java.nio.DoubleBuffer类的asReadOnlyBuffer()方法用于使用该缓冲区的内容创建一个新的只读双缓冲区。新缓冲区是此缓冲区的副本。因此，对该缓冲区内容所做的更改将在新缓冲区中可见。

由于新缓冲区是只读缓冲区，因此不允许对其内容进行任何修改。这两个缓冲区的位置，限制和标记值将是独立的。新缓冲区的容量，限制，位置和标记值将与此缓冲区相同。如果此缓冲区本身是只读的，则此方法的行为与重复方法完全相同。

用法:

public abstract DoubleBuffer asReadOnlyBuffer()

返回值：此方法返回新的只读双缓冲区，其内容与此缓冲区相同。

下面是说明asReadOnlyBuffer()方法的示例：

示例1:

// Java program to demonstrate 
// asReadOnlyBuffer() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        // Declaring the capacity of the DoubleBuffer 
        int capacity = 10; 
  
        // Creating the DoubleBuffer 
        try { 
  
            // creating object of floatbuffer 
            // and allocating size capacity 
            DoubleBuffer db = DoubleBuffer.allocate(capacity); 
  
            // putting the value in floatbuffer 
            db.put(8.56); 
            db.put(2, 9.61); 
            db.rewind(); 
  
            // print the DoubleBuffer 
            System.out.println("Original DoubleBuffer: "
                               + Arrays.toString(db.array())); 
  
            // Creating a read-only copy of DoubleBuffer 
            // using asReadOnlyBuffer() method 
            DoubleBuffer floatBuffer = db.asReadOnlyBuffer(); 
  
            // print the DoubleBuffer 
            System.out.print("\nReadOnlyBuffer DoubleBuffer: "); 
  
            while (floatBuffer.hasRemaining()) 
                System.out.print(floatBuffer.get() + ", "); 
        } 
  
        catch (IllegalArgumentException e) { 
  
            System.out.println("IllegalArgumentException catched"); 
        } 
  
        catch (ReadOnlyBufferException e) { 
  
            System.out.println("ReadOnlyBufferException catched"); 
        } 
    } 
}

输出：

Original DoubleBuffer: [8.56, 0.0, 9.61, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]

ReadOnlyBuffer DoubleBuffer: 8.56, 0.0, 9.61, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0,

示例2:

// Java program to demonstrate 
// asReadOnlyBuffer() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
  
    public static void main(String[] args) throws Exception 
    { 
  
        // Declaring the capacity of the db 
        int capacity1 = 10; 
  
        // Declaring the capacity of the db1 
        int capacity2 = 5; 
  
        // Creating the DoubleBuffer 
        try { 
  
            // 
            // db 
            // 
            // creating object of Doublebuffer db 
            // and allocating size capacity 
            DoubleBuffer db = DoubleBuffer.allocate(capacity1); 
  
            // putting the value in db 
            db.put(8.56); 
            db.put(2, 9.61); 
            db.rewind(); 
  
            // print the DoubleBuffer 
            System.out.println("DoubleBuffer db: "
                               + Arrays.toString(db.array())); 
  
            // 
            // db1 
            // 
            // creating object of Doublebuffer db1 
            // and allocating size capacity 
            DoubleBuffer db1 = DoubleBuffer.allocate(capacity2); 
  
            // putting the value in db1 
            db1.put(1, 4.56); 
            db1.put(2, 6.45); 
            db1.rewind(); 
  
            // print the DoubleBuffer 
            System.out.println("\nDoubleBuffer db1: "
                               + Arrays.toString(db1.array())); 
  
            // Creating a read-only copy of DoubleBuffer 
            // using asReadOnlyBuffer() method 
            DoubleBuffer readOnlyDb = db.asReadOnlyBuffer(); 
  
            // print the DoubleBuffer 
            System.out.print("\nReadOnlyBuffer DoubleBuffer: "); 
  
            while (readOnlyDb.hasRemaining()) 
                System.out.print(readOnlyDb.get() + ", "); 
  
            // try to change readOnlyDb 
            System.out.println("\n\nTrying to get the array"
                               + " from ReadOnlyDb for editing"); 
            Arrays.toString(readOnlyDb.array()); 
        } 
        catch (IllegalArgumentException e) { 
            System.out.println("IllegalArgumentException catched"); 
        } 
        catch (ReadOnlyBufferException e) { 
            System.out.println("Exception thrown: " + e); 
        } 
    } 
}

输出：

DoubleBuffer db: [8.56, 0.0, 9.61, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]

DoubleBuffer db1: [0.0, 4.56, 6.45, 0.0, 0.0]

ReadOnlyBuffer DoubleBuffer: 8.56, 0.0, 9.61, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 

Trying to get the array from ReadOnlyDb for editing
Exception thrown: 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 DoubleBuffer asReadOnlyBuffer() method in Java with Examples。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。