Java DoubleBuffer asReadOnlyBuffer()用法及代碼示例

java.nio.DoubleBuffer類的asReadOnlyBuffer()方法用於使用該緩衝區的內容創建一個新的隻讀雙緩衝區。新緩衝區是此緩衝區的副本。因此，對該緩衝區內容所做的更改將在新緩衝區中可見。

由於新緩衝區是隻讀緩衝區，因此不允許對其內容進行任何修改。這兩個緩衝區的位置，限製和標記值將是獨立的。新緩衝區的容量，限製，位置和標記值將與此緩衝區相同。如果此緩衝區本身是隻讀的，則此方法的行為與重複方法完全相同。

用法:

public abstract DoubleBuffer asReadOnlyBuffer()

返回值：此方法返回新的隻讀雙緩衝區，其內容與此緩衝區相同。

下麵是說明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"); 
        } 
    } 
}

輸出：

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); 
        } 
    } 
}

輸出：

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

相關用法

注：本文由純淨天空篩選整理自pawan_asipu大神的英文原創作品 DoubleBuffer asReadOnlyBuffer() method in Java with Examples。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。