Java 中的 IntBuffer compact()方法
原文:https://www . geesforgeks . org/int buffer-compact-method-in-Java/
java.nio.IntBuffer 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，缓冲器的位置被设置为 n+1，其极限被设置为其容量。缓冲区的位置被设置为复制的浮点数。
语法:
public abstract IntBuffer compact()
返回值:该方法返回与该缓冲区内容相同的新的 IntBuffer 。
异常:如果这个缓冲区是只读的，这个方法抛出readonlybufferrexception。
下面的程序说明了紧凑()的方法:
实施例 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 IntBuffer
int capacity = 10;
// Creating the IntBuffer
// creating object of Intbuffer
// and allocating size capacity
IntBuffer ib = IntBuffer.allocate(capacity);
// putting the value in Intbuffer
ib.put(8);
ib.put(9);
ib.put(9);
// print the IntBuffer
System.out.println("Original IntBuffer: "
+ Arrays.toString(ib.array()));
System.out.println("Position: " + ib.position());
System.out.println("limit: " + ib.limit());
// Creating a compacted IntBuffer of same IntBuffer
// using compact() method
IntBuffer IntBuffer = ib.compact();
// print the IntBuffer
System.out.println("\nCompacted IntBuffer: "
+ Arrays.toString(IntBuffer.array()));
System.out.println("Position: " + IntBuffer.position());
System.out.println("limit: " + IntBuffer.limit());
// putting the value in compacted Intbuffer
IntBuffer.put(9);
// print the IntBuffer
System.out.println("\nUpdated Compacted IntBuffer: "
+ Arrays.toString(IntBuffer.array()));
System.out.println("Position: " + IntBuffer.position());
System.out.println("limit: " + IntBuffer.limit());
}
}
Output:
Original IntBuffer: [8, 9, 9, 0, 0, 0, 0, 0, 0, 0]
Position: 3
limit: 10
Compacted IntBuffer: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
Position: 7
limit: 10
Updated Compacted IntBuffer: [0, 0, 0, 0, 0, 0, 0, 9, 0, 0]
Position: 8
limit: 10
示例 2: 演示 ReadOnlyBufferException
// 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 IntBuffer
int capacity = 10;
// Creating the IntBuffer
try {
// creating object of IntBuffer
// and allocating size capacity
IntBuffer ib = IntBuffer.allocate(capacity);
// putting the value in Intbuffer
ib.put(8);
ib.put(9);
ib.put(9);
ib.rewind();
// Creating a read-only copy of IntBuffer
// using asReadOnlyBuffer() method
IntBuffer ib1 = ib.asReadOnlyBuffer();
// print the ReadOnlyBuffer
System.out.print("ReadOnlyBuffer IntBuffer: ");
while (ib1.hasRemaining())
System.out.print(ib1.get() + ", ");
System.out.println("");
// print the Position of IntBuffer ib
System.out.println("\nPosition: " + ib.position());
// print the Limit of IntBuffer ib
System.out.println("\nlimit: " + ib.limit());
// Creating a compacted IntBuffer of same ReadOnlyBuffer
// using compact() method
System.out.println("\nTrying to compact the ReadOnlyBuffer ib1");
IntBuffer IntBuffer = ib1.compact();
}
catch (IllegalArgumentException e) {
System.out.println("Exception throws " + e);
}
catch (ReadOnlyBufferException e) {
System.out.println("Exception throws " + e);
}
}
}
Output:
ReadOnlyBuffer IntBuffer: 8, 9, 9, 0, 0, 0, 0, 0, 0, 0,
Position: 0
limit: 10
Trying to compact the ReadOnlyBuffer ib1
Exception throws java.nio.ReadOnlyBufferException
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