DoubleBuffer compact() method in Java With Examples
The compact() method of java.nio.DoubleBuffer Class is used to compact the given buffer.
The values between the buffer’s current position and its limit are copied to the beginning of the buffer. The buffer’s position is then set to n+1 and its limit is set to its capacity. The buffer’s position is set to the number of floats copied.
Syntax :
public abstract DoubleBuffer compact()
Return Value: This method returns the new DoubleBuffer with the same content as that of this buffer.
Exception: This method throws the ReadOnlyBufferException, If this buffer is read-only.
Below program illustrates the compact() method:
Examples 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 DoubleBuffer int capacity = 10 ; // Creating the DoubleBuffer // creating object of Doublebuffer // and allocating size capacity DoubleBuffer db = DoubleBuffer.allocate(capacity); // putting the value in Doublebuffer db.put( 8 .56F); db.put( 9 .61F); db.put( 9 .61F); // print the DoubleBuffer System.out.println( "Original DoubleBuffer: " + Arrays.toString(db.array())); System.out.println( "Position: " + db.position()); System.out.println( "limit: " + db.limit()); // Creating a compacted DoubleBuffer of same DoubleBuffer // using compact() method DoubleBuffer DoubleBuffer = db.compact(); // print the DoubleBuffer System.out.println( "\nCompacted DoubleBuffer: " + Arrays.toString(DoubleBuffer.array())); System.out.println( "Position: " + DoubleBuffer.position()); System.out.println( "limit: " + DoubleBuffer.limit()); // putting the value in compacted Doublebuffer DoubleBuffer.put( 9 .61F); // print the DoubleBuffer System.out.println( "\nUpdated Compacted DoubleBuffer: " + Arrays.toString(DoubleBuffer.array())); System.out.println( "Position: " + DoubleBuffer.position()); System.out.println( "limit: " + DoubleBuffer.limit()); } } |
Output:
Original DoubleBuffer: [8.5600004196167, 9.609999656677246, 9.609999656677246, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0] Position: 3 limit: 10 Compacted DoubleBuffer: [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 DoubleBuffer: [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 9.609999656677246, 0.0, 0.0] Position: 8 limit: 10
Examples 2: To show 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 DoubleBuffer int capacity = 10 ; // Creating the DoubleBuffer try { // creating object of DoubleBuffer // and allocating size capacity DoubleBuffer db = DoubleBuffer.allocate(capacity); // putting the value in Doublebuffer db.put( 8 .56F); db.put( 9 .61F); db.put( 9 .61F); db.rewind(); // Creating a read-only copy of DoubleBuffer // using asReadOnlyBuffer() method DoubleBuffer db1 = db.asReadOnlyBuffer(); // print the ReadOnlyBuffer System.out.print( "ReadOnlyBuffer DoubleBuffer: " ); while (db1.hasRemaining()) System.out.print(db1.get() + ", " ); System.out.println( "" ); // print the Position of DoubleBuffer db System.out.println( "\nPosition: " + db.position()); // print the Limit of DoubleBuffer db System.out.println( "\nlimit: " + db.limit()); // Creating a compacted DoubleBuffer of same ReadOnlyBuffer // using compact() method System.out.println( "\nTrying to compact the ReadOnlyBuffer db1" ); DoubleBuffer DoubleBuffer = db1.compact(); } catch (IllegalArgumentException e) { System.out.println( "Exception throws " + e); } catch (ReadOnlyBufferException e) { System.out.println( "Exception throws " + e); } } } |
Output:
ReadOnlyBuffer DoubleBuffer: 8.5600004196167, 9.609999656677246, 9.609999656677246, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, Position: 0 limit: 10 Trying to compact the ReadOnlyBuffer db1 Exception throws java.nio.ReadOnlyBufferException
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