Java中的 FloatBuffer compact() 方法及示例
Java.nio.FloatBuffer类的compact()方法用于压缩给定的缓冲区。
缓冲区的当前位置与其限制之间的值被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。
句法 :
public abstract FloatBuffer compact()
返回值:该方法返回与该缓冲区内容相同的新FloatBuffer 。
异常:此方法抛出ReadOnlyBufferException ,如果此缓冲区是只读的。
下面的程序说明了compact()方法:
示例 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 FloatBuffer
int capacity = 10;
// Creating the FloatBuffer
// creating object of floatbuffer
// and allocating size capacity
FloatBuffer fb = FloatBuffer.allocate(capacity);
// putting the value in floatbuffer
fb.put(8.56F);
fb.put(9.61F);
fb.put(9.61F);
// print the FloatBuffer
System.out.println("Original FloatBuffer: "
+ Arrays.toString(fb.array()));
System.out.println("Position: " + fb.position());
System.out.println("limit: " + fb.limit());
// Creating a compacted FloatBuffer of same FloatBuffer
// using compact() method
FloatBuffer floatBuffer = fb.compact();
// print the FloatBuffer
System.out.println("\nCompacted FloatBuffer: "
+ Arrays.toString(floatBuffer.array()));
System.out.println("Position: " + floatBuffer.position());
System.out.println("limit: " + floatBuffer.limit());
// putting the value in compacted floatbuffer
floatBuffer.put(9.61F);
// print the FloatBuffer
System.out.println("\nUpdated Compacted FloatBuffer: "
+ Arrays.toString(floatBuffer.array()));
System.out.println("Position: " + floatBuffer.position());
System.out.println("limit: " + floatBuffer.limit());
}
}
输出:
Original FloatBuffer: [8.56, 9.61, 9.61, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]
Position: 3
limit: 10
Compacted FloatBuffer: [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]
Position: 7
limit: 10
Updated Compacted FloatBuffer: [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 9.61, 0.0, 0.0]
Position: 8
limit: 10
示例 2:
// 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 FloatBuffer
int capacity = 10;
// Creating the FloatBuffer
try {
// creating object of FloatBuffer
// and allocating size capacity
FloatBuffer fb = FloatBuffer.allocate(capacity);
// putting the value in floatbuffer
fb.put(8.56F);
fb.put(9.61F);
fb.put(9.61F);
fb.rewind();
// Creating a read-only copy of FloatBuffer
// using asReadOnlyBuffer() method
FloatBuffer fb1 = fb.asReadOnlyBuffer();
// print the ReadOnlyBuffer
System.out.print("ReadOnlyBuffer FloatBuffer: ");
while (fb1.hasRemaining())
System.out.print(fb1.get() + ", ");
System.out.println("");
// print the Position of FloatBuffer fb
System.out.println("\nPosition: " + fb.position());
// print the Limit of FloatBuffer fb
System.out.println("\nlimit: " + fb.limit());
// Creating a compacted FloatBuffer of same ReadOnlyBuffer
// using compact() method
System.out.println("\nTrying to compact the ReadOnlyBuffer fb1");
FloatBuffer floatBuffer = fb1.compact();
}
catch (IllegalArgumentException e) {
System.out.println("Exception throws " + e);
}
catch (ReadOnlyBufferException e) {
System.out.println("Exception throws " + e);
}
}
}
输出:
ReadOnlyBuffer FloatBuffer: 8.56, 9.61, 9.61, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0,
Position: 0
limit: 10
Trying to compact the ReadOnlyBuffer fb1
Exception throws java.nio.ReadOnlyBufferException