java.nio.DoubleBuffer類的mark()方法用於將此DoubleBuffer的當前位置標記為該緩衝區的標記。
用法:
public DoubleBuffer mark()
返回值:在將緩衝區的標記設置在當前位置之後,此方法將返回此DoubleBuffer。
下麵是說明mark()方法的示例:
範例1:
// Java program to demonstrate
// mark() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
try {
double[] darr = { 10.5, 20.5, 30.5, 40.5 };
// 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 reset() to restore
// to the position we marked
db.reset();
// display position
System.out.println("position after reset:"
+ db.position());
}
catch (InvalidMarkException e) {
System.out.println("New position "
+ "is less than "
+ "the position "
+ "marked before ");
System.out.println("Exception throws:"
+ e);
}
}
}
輸出:
position before reset:4 position after reset:2
範例2:演示InvalidMarkException
// Java program to demonstrate
// mark() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
try {
double[] darr = { 10.5, 20.5, 30.5, 40.5 };
// 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 1
db.position(1);
// display position
System.out.println("position before reset:"
+ db.position());
// try to call reset() to restore
// to the position we marked
db.reset();
// display position
System.out.println("position after reset:"
+ db.position());
}
catch (InvalidMarkException e) {
System.out.println("\nNew position "
+ "is less than "
+ "the position "
+ "marked before ");
System.out.println("Exception throws:"
+ e);
}
}
}
輸出:
position before reset:1 New position is less than the position marked before Exception throws:java.nio.InvalidMarkException
參考: https://docs.oracle.com/javase/9/docs/api/java/nio/DoubleBuffer.html#mark-
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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 mark() 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。