Java DoubleBuffer clear()用法及代碼示例

java.nio.CharBuffer類的clear()方法用於清除此緩衝區。在清除此緩衝區時，需要進行以下更改：

位置設置為零
限製設置為容量
商標被丟棄。

用法:

public final DoubleBuffer clear()

返回值：從其中清除所有數據後，此方法將返回此DoubleBuffer實例。

下麵是說明clear()方法的示例：

範例1：

// Java program to demonstrate 
// clear() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        try { 
  
            double[] darr = { 2.5, 3.5, 4.5, 6.7 }; 
  
            // creating object of DoubleBuffer 
            // and allocating size capacity 
            DoubleBuffer db 
                = DoubleBuffer.wrap(darr); 
  
            // try to set the position at index 2 
            db.position(2); 
  
            // Set this buffer mark position 
            // using mark() method 
            db.mark(); 
  
            // try to set the position at index 4 
            db.position(4); 
  
            // display position 
            System.out.println("position before reset:"
                               + db.position()); 
  
            // try to call clear() to restore 
            // to the position at index 0 
            // by discarding the mark 
            db.clear(); 
  
            // display position 
            System.out.println("position after reset:"
                               + db.position()); 
        } 
  
        catch (InvalidMarkException e) { 
            System.out.println("new position is less than "
                               + "the position we "
                               + "marked before "); 
            System.out.println("Exception throws:" + e); 
        } 
    } 
}

輸出：

position before reset:4
position after reset:0

範例2：

// Java program to demonstrate 
// clear() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        double[] carr = { 2.4, 105.4, 13.9, 23.45d }; 
  
        // creating object of DoubleBuffer 
        // and allocating size capacity 
        DoubleBuffer db = DoubleBuffer.wrap(carr); 
  
        // try to set the position at index 3 
        db.position(3); 
  
        // display position 
        System.out.println("position before clear:"
                           + db.position()); 
  
        // try to call clear() to restore 
        // to the position at index 0 
        // by discarding the mark 
        db.clear(); 
  
        // display position 
        System.out.println("position after clear:"
                           + db.position()); 
    } 
}

輸出：

position before clear:3
position after clear:0

參考： https://docs.oracle.com/javase/9/docs/api/java/nio/DoubleBuffer.html#clear-

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注：本文由純淨天空篩選整理自RohitPrasad3大神的英文原創作品 DoubleBuffer clear() methods 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。