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Java Fundamental Classes Reference

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The java.io Package
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CharArrayWriter

Name

CharArrayWriter

Synopsis

Class Name:

java.io.CharArrayWriter

Superclass:

java.io.Writer

Immediate Subclasses:

None

Interfaces Implemented:

None

Availability:

New as of JDK 1.1

Description

The CharArrayWriter class represents a stream whose data is written to an internal character array. This class is similar to ByteArrayOutputStream, but it operates on an array of Java characters instead of a byte array.

The data from a CharArrayWriter can be sent to another Writer using the writeTo() method. A copy of the array can be obtained using the toCharArray() method.

Class Summary

public class java.io.CharArrayWriter extends java.io.Writer {
  // Variables
  protected char[] buf;
  protected int count;
  // Constructors
  public CharArrayWriter();
  public CharArrayWriter(int initialSize);
  // Instance Methods
  public void close();
  public void flush();
  public void reset();
  public int size();
  public char[] toCharArray();
  public String toString();
  public void write(int c);
  public void write(char[] c, int off, int len);
  public void write(String str, int off, int len);
  public void writeTo(Writer out);
}

Variables

buf

protected char[] buf

Description

The buffer that holds data for this stream.

count

protected int count

Description

A placeholder that marks the end of the data in the buffer.

Constructors

CharArrayWriter

public CharArrayWriter()

Description

This constructor creates a CharArrayWriter with an internal buffer that has a default size of 32 characters. The buffer grows automatically as data is written to the stream.

public CharArrayWriter(int initialSize)

Parameters

initialSize

The initial buffer size.

Description

This constructor creates a CharArrayWriter with an internal buffer that has a size of initialSize characters. The buffer grows automatically as data is written to the stream.

Instance Methods

close

public void close()

Overrides

Writer.close()

Description

This method does nothing. For most subclasses of Writer, this method releases any system resources that are associated with the Writer object. However, the CharArrayWriter's internal array may be needed for subsequent calls to toCharArray() or writeTo(). For this reason, close() does nothing, and the internal array is not released until the CharArrayWriter is garbage collected.

flush

public void flush()

Overrides

Writer.flush()

Description

This method does nothing. The CharArrayWriter writes data directly into its internal array; thus it is never necessary to flush the stream.

reset

public void reset()

Description

This method discards the current contents of the buffer and resets the position of the stream to zero. Subsequent data is written starting at the beginning of the array.

size

public int size()

Description

This method returns the number of characters currently stored in this object's internal buffer. It is a count of the number of characters that have been written to the stream.

toCharArray

public char[] toCharArray()

Returns

A copy of the data that has been written to this CharArrayWriter in the form of a char array.

Description

This method copies the data in the internal array and returns a reference to the copy. The returned array is as long as the data that has been written to the stream, i.e., the same as size().

toString

public String toString()

Returns

A copy of the data that has been written to this CharArrayWriter in the form of a String.

Overrides

Object.toString()

Description

This method returns a reference to a String object created from the characters stored in this object's internal buffer.

write

public void write(int c)

Parameters

c

The value to write.

Overrides

Writer.write(int)

Description

This method writes the low-order 16 bits of the given value into the internal array. If the array is full, a larger array is allocated.

public void write(char[] c, int off, int len)

Parameters

c

An array of characters to write to the stream.

off

An offset into the character array.

len

The number of characters to write.

Overrides

Writer.write(char[], int, int)

Description

This method copies len characters to this object's internal array from c, starting off elements from the beginning of the array. If the internal array is full, a larger array is allocated.

public void write(String str, int off, int len)

Parameters

str

A String to write to the stream.

off

An offset into the string.

len

The number of characters to write.

Overrides

Writer.write(String, int, int)

Description

This method copies len characters to this object's internal array from str, starting off characters from the beginning of the given string. If the internal array is full, a larger array is allocated.

writeTo

public void writeTo(Writer out) throws IOException

Parameters

out

The destination stream.

Throws

IOException

If any kind of I/O error occurs.

Description

This method writes the contents of this object's internal buffer to the given Writer. All the data that has been written to this CharArrayWriter is written to out.

Inherited Methods

Method

Inherited From

Method

Inherited From

clone()

Object

equals(Object)

Object

finalize()

Object

getClass()

Object

hashCode()

Object

notify()

Object

notifyAll()

Object

wait()

Object

wait(long)

Object

wait(long, int)

Object

write(char[])

Writer

write(String)

Writer

See Also

IOException, String, Writer


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