Module java.base
Package java.io

Class CharArrayWriter

java.lang.Object
java.io.Writer
java.io.CharArrayWriter
All Implemented Interfaces:
Closeable, Flushable, Appendable, AutoCloseable
public class CharArrayWriter
extends Writer
This class implements a character buffer that can be used as an Writer. The buffer automatically grows when data is written to the stream. The data can be retrieved using toCharArray() and toString().

Note: Invoking close() on this class has no effect, and methods of this class can be called after the stream has closed without generating an IOException.

Since:
1.1

  • Field Summary

    Fields 
    Modifier and Type Field Description
    protected char[] buf
    The buffer where data is stored.
    protected int count
    The number of chars in the buffer.

    Fields declared in class java.io.Writer

    lock

  • Constructor Summary

    Constructors 
    Constructor Description
    CharArrayWriter()
    Creates a new CharArrayWriter.
    CharArrayWriter​(int initialSize)
    Creates a new CharArrayWriter with the specified initial size.

  • Method Summary

    Modifier and Type Method Description
    CharArrayWriter append​(char c)
    Appends the specified character to this writer.
    CharArrayWriter append​(CharSequence csq)
    Appends the specified character sequence to this writer.
    CharArrayWriter append​(CharSequence csq, int start, int end)
    Appends a subsequence of the specified character sequence to this writer.
    void close()
    Close the stream.
    void flush()
    Flush the stream.
    void reset()
    Resets the buffer so that you can use it again without throwing away the already allocated buffer.
    int size()
    Returns the current size of the buffer.
    char[] toCharArray()
    Returns a copy of the input data.
    String toString()
    Converts input data to a string.
    void write​(char[] c, int off, int len)
    Writes characters to the buffer.
    void write​(int c)
    Writes a character to the buffer.
    void write​(String str, int off, int len)
    Write a portion of a string to the buffer.
    void writeTo​(Writer out)
    Writes the contents of the buffer to another character stream.

    Methods declared in class java.io.Writer

    nullWriter, write, write

    Methods declared in class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

  • Field Details

    • buf

      protected char[] buf
      The buffer where data is stored.

    • count

      protected int count
      The number of chars in the buffer.

  • Constructor Details

    • CharArrayWriter

      public CharArrayWriter()
      Creates a new CharArrayWriter.

    • CharArrayWriter

      public CharArrayWriter​(int initialSize)
      Creates a new CharArrayWriter with the specified initial size.
      Parameters:
      initialSize - an int specifying the initial buffer size.
      Throws:
      IllegalArgumentException - if initialSize is negative

  • Method Details

    • write

      public void write​(int c)
      Writes a character to the buffer.
      Overrides:
      write in class Writer
      Parameters:
      c - int specifying a character to be written

    • write

      public void write​(char[] c, int off, int len)
      Writes characters to the buffer.
      Specified by:
      write in class Writer
      Parameters:
      c - the data to be written
      off - the start offset in the data
      len - the number of chars that are written
      Throws:
      IndexOutOfBoundsException - If off is negative, or len is negative, or off + len is negative or greater than the length of the given array

    • write

      public void write​(String str, int off, int len)
      Write a portion of a string to the buffer.
      Overrides:
      write in class Writer
      Parameters:
      str - String to be written from
      off - Offset from which to start reading characters
      len - Number of characters to be written
      Throws:
      IndexOutOfBoundsException - If off is negative, or len is negative, or off + len is negative or greater than the length of the given string

    • writeTo

      public void writeTo​(Writer out) throws IOException
      Writes the contents of the buffer to another character stream.
      Parameters:
      out - the output stream to write to
      Throws:
      IOException - If an I/O error occurs.

    • append

      public CharArrayWriter append​(CharSequence csq)
      Appends the specified character sequence to this writer.

      An invocation of this method of the form out.append(csq) behaves in exactly the same way as the invocation 

           out.write(csq.toString())

      Depending on the specification of toString for the character sequence csq, the entire sequence may not be appended. For instance, invoking the toString method of a character buffer will return a subsequence whose content depends upon the buffer's position and limit.

      Specified by:
      append in interface Appendable
      Overrides:
      append in class Writer
      Parameters:
      csq - The character sequence to append. If csq is null, then the four characters "null" are appended to this writer.
      Returns:
      This writer
      Since:
      1.5

    • append

      public CharArrayWriter append​(CharSequence csq, int start, int end)
      Appends a subsequence of the specified character sequence to this writer.

      An invocation of this method of the form out.append(csq, start, end) when csq is not null, behaves in exactly the same way as the invocation 

           out.write(csq.subSequence(start, end).toString())

      Specified by:
      append in interface Appendable
      Overrides:
      append in class Writer
      Parameters:
      csq - The character sequence from which a subsequence will be appended. If csq is null, then characters will be appended as if csq contained the four characters "null".
      start - The index of the first character in the subsequence
      end - The index of the character following the last character in the subsequence
      Returns:
      This writer
      Throws:
      IndexOutOfBoundsException - If start or end are negative, start is greater than end, or end is greater than csq.length()
      Since:
      1.5

    • append

      public CharArrayWriter append​(char c)
      Appends the specified character to this writer.

      An invocation of this method of the form out.append(c) behaves in exactly the same way as the invocation 

           out.write(c)

      Specified by:
      append in interface Appendable
      Overrides:
      append in class Writer
      Parameters:
      c - The 16-bit character to append
      Returns:
      This writer
      Since:
      1.5

    • reset

      public void reset()
      Resets the buffer so that you can use it again without throwing away the already allocated buffer.

    • toCharArray

      public char[] toCharArray()
      Returns a copy of the input data.
      Returns:
      an array of chars copied from the input data.

    • size

      public int size()
      Returns the current size of the buffer.
      Returns:
      an int representing the current size of the buffer.

    • toString

      public String toString()
      Converts input data to a string.
      Overrides:
      toString in class Object
      Returns:
      the string.

    • flush

      public void flush()
      Flush the stream.
      Specified by:
      flush in interface Flushable
      Specified by:
      flush in class Writer

    • close

      public void close()
      Close the stream. This method does not release the buffer, since its contents might still be required. Note: Invoking this method in this class will have no effect.
      Specified by:
      close in interface AutoCloseable
      Specified by:
      close in interface Closeable
      Specified by:
      close in class Writer