java.nio.CharBuffer Class in Java
Last Updated :
29 Mar, 2021
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CharBuffer holds a sequence of integer values to be used in an I/O operation. The CharBuffer class provides the following four categories of operations upon long buffers:
- Absolute and relative get method that read single Chars.
- Absolute and relative put methods that write single Chars.
- Relative bulk put and get methods that transfer contiguous sequences of Chars from an int array or some other Chars buffer into this buffer and from this buffer into an array.
Short buffers can be created by:
- allocate(): This allocates space for the buffer’s content.
- wrap(): This wraps an existing long array into a buffer.
Most of the methods of CharBuffer class are directly analogous to the methods defined by ByteBuffer.
Class Declaration:
public abstract class CharBuffer
extends Buffer
implements Comparable<CharBuffer>, Appendable, CharSequence, Readable
Methods of CharBuffer class:
| Method | Description |
|---|---|
| allocate(int capacity) | This method allocates a new char buffer. |
| append(char c) | This method appends the specified char to this buffer. |
| append(CharSequence csq) | This method appends the specified character sequence to this buffer. |
| append(CharSequence csq, int start, int end) | This method appends a subsequence of the specified character sequence to this buffer |
| array() | This method returns the char array that backs this buffer |
| arrayOffset() | This method returns the offset within this buffer’s backing array of the first element of the buffer |
| asReadOnlyBuffer() | This method creates a new, read-only char buffer that shares this buffer’s content. |
| charAt(int index) | This method reads the character at the given index relative to the current position. |
| compact() | This method compacts this buffer |
| compareTo(CharBuffer that) | This method compares this buffer to another. |
| duplicate() | This method creates a new char buffer that shares this buffer’s content. |
| equals(Object ob) | This method tells whether this buffer is equal to another object. |
| get() | This method is a relative get method and returns |
| get(char[] dst) | This method is a relative bulk get method and returns |
| get(char[] dst, int offset, int length) | This method is a relative bulk get method and returns |
| get(int index) | This method is an absolute get method and returns |
| hasArray() | This method tells whether this buffer is backed by an accessible char array. |
| hashCode() | This method returns the current hash code of this buffer. |
| isDirect() | This method tells whether this char buffer is direct. |
| length() | This method returns the length of this character buffer. |
| order() | This method retrieves this buffer’s byte order. |
| put(char c) | This method is a relative put method and returns |
| put(char[] src) | This method is a relative bulk put method and returns |
| put(char[] src, int offset, int length) | This method is a relative bulk put method and returns |
| put(CharBuffer src) | This method is a relative bulk put method and returns |
| put(int index, char c) | This method is an absolute put method and returns |
| put(String src) | This method is a relative bulk put method and returns |
| put(String src, int start, int end) | This method is a relative bulk put method and returns |
| read(CharBuffer target) | This method attempts to read characters into the specified character buffer. |
| slice() | This method creates a new char buffer whose content is a shared subsequence of this buffer’s content. |
| subSequence(int start, int end) | This method creates a new character buffer that represents the specified subsequence of this buffer, relative to the current position. |
| toString() | This method returns a string containing the characters in this buffer. |
| wrap(char[] array) | This method wraps a char array into a buffer. |
| wrap(char[] array, int offset, int length) | This method wraps a char array into a buffer. |
| wrap(CharSequence csq) | This method wraps a character sequence into a buffer. |
| wrap(CharSequence csq, int start, int end) | This method wraps a character sequence into a buffer. |
Following are some programs to demonstrate CharBuffer class and its methods:
Example 1:
- Java
Java
// Java program to demonstrate // CharBuffer class import java.nio.*; import java.util.*; public class GFG { public static void main(String[] args) { // Declaring the capacity of the CharBuffer char capacity = 10; // Creating the CharBuffer // creating object of Charbuffer // and allocating size capacity CharBuffer fb = CharBuffer.allocate(capacity); // putting the value in charbuffer fb.put('a'); fb.put(5, 'b'); fb.put(7, 'c'); // Printing the CharBuffer System.out.println("ChartBuffer: " + Arrays.toString(fb.array())); } } |
Output:
ChartBuffer: [a, , , , , b, , c, , ]
Example 2:
- Java
Java
// Java program to demonstrate // CharBuffer class import java.nio.*; import java.util.*; public class GFG { public static void main(String[] args) { // Declaring the capacity of the CharBuffer int capacity = 4; // Creating the CharBuffer try { // creating object of CharBuffer // and allocating size capacity CharBuffer charbuffer = CharBuffer.allocate(capacity); // append the value in CharBuffer // using append() method charbuffer.append('a') .append('b') .append('c') .append('d') .rewind(); // print the CharBuffer System.out.println("Original CharBuffer: " + Arrays.toString( charbuffer.array())); } catch (BufferOverflowException e) { System.out.println("Exception throws : " + e); } catch (ReadOnlyBufferException e) { System.out.println("Exception throws : " + e); } } } |
Output:
Original CharBuffer: [a, b, c, d]
