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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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package java.io;



A character stream that collects its output in a string buffer, which can
then be used to construct a string.


Closing a StringWriter has no effect. The methods in this class
can be called after the stream has been closed without generating an
IOException.

Author:     Mark Reinhold
Since:      JDK1.1
/**
 * A character stream that collects its output in a string buffer, which can
 * then be used to construct a string.
 * <p>
 * Closing a <tt>StringWriter</tt> has no effect. The methods in this class
 * can be called after the stream has been closed without generating an
 * <tt>IOException</tt>.
 *
 * @author      Mark Reinhold
 * @since       JDK1.1
 */

public class StringWriter extends Writer {

    private StringBuffer buf;

    
Create a new string writer using the default initial string-buffer
size.

/**
     * Create a new string writer using the default initial string-buffer
     * size.
     */
    public StringWriter() {
        buf = new StringBuffer();
        lock = buf;
    }

    
Create a new string writer using the specified initial string-buffer
size.

Params:
  • initialSize – 
       The number of char values that will fit into this buffer
       before it is automatically expanded
Throws:
/**
     * Create a new string writer using the specified initial string-buffer
     * size.
     *
     * @param initialSize
     *        The number of <tt>char</tt> values that will fit into this buffer
     *        before it is automatically expanded
     *
     * @throws IllegalArgumentException
     *         If <tt>initialSize</tt> is negative
     */
    public StringWriter(int initialSize) {
        if (initialSize < 0) {
            throw new IllegalArgumentException("Negative buffer size");
        }
        buf = new StringBuffer(initialSize);
        lock = buf;
    }

    
Write a single character.

/**
     * Write a single character.
     */
    public void write(int c) {
        buf.append((char) c);
    }

    
Write a portion of an array of characters.

Params:
  • cbuf –  Array of characters
  • off –   Offset from which to start writing characters
  • len –   Number of characters to write
/**
     * Write a portion of an array of characters.
     *
     * @param  cbuf  Array of characters
     * @param  off   Offset from which to start writing characters
     * @param  len   Number of characters to write
     */
    public void write(char cbuf[], int off, int len) {
        if ((off < 0) || (off > cbuf.length) || (len < 0) ||
            ((off + len) > cbuf.length) || ((off + len) < 0)) {
            throw new IndexOutOfBoundsException();
        } else if (len == 0) {
            return;
        }
        buf.append(cbuf, off, len);
    }

    
Write a string.

/**
     * Write a string.
     */
    public void write(String str) {
        buf.append(str);
    }

    
Write a portion of a string.

Params:
  • str –  String to be written
  • off –  Offset from which to start writing characters
  • len –  Number of characters to write
/**
     * Write a portion of a string.
     *
     * @param  str  String to be written
     * @param  off  Offset from which to start writing characters
     * @param  len  Number of characters to write
     */
    public void write(String str, int off, int len)  {
        buf.append(str.substring(off, off + len));
    }

    
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.

Params:
  • 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
/**
     * Appends the specified character sequence to this writer.
     *
     * <p> An invocation of this method of the form <tt>out.append(csq)</tt>
     * behaves in exactly the same way as the invocation
     *
     * <pre>
     *     out.write(csq.toString()) </pre>
     *
     * <p> Depending on the specification of <tt>toString</tt> for the
     * character sequence <tt>csq</tt>, the entire sequence may not be
     * appended. For instance, invoking the <tt>toString</tt> method of a
     * character buffer will return a subsequence whose content depends upon
     * the buffer's position and limit.
     *
     * @param  csq
     *         The character sequence to append.  If <tt>csq</tt> is
     *         <tt>null</tt>, then the four characters <tt>"null"</tt> are
     *         appended to this writer.
     *
     * @return  This writer
     *
     * @since  1.5
     */
    public StringWriter append(CharSequence csq) {
        if (csq == null)
            write("null");
        else
            write(csq.toString());
        return this;
    }

    
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()) 


Params:
  • 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
Throws:
Returns: This writer
Since: 1.5
/**
     * Appends a subsequence of the specified character sequence to this writer.
     *
     * <p> An invocation of this method of the form <tt>out.append(csq, start,
     * end)</tt> when <tt>csq</tt> is not <tt>null</tt>, behaves in
     * exactly the same way as the invocation
     *
     * <pre>
     *     out.write(csq.subSequence(start, end).toString()) </pre>
     *
     * @param  csq
     *         The character sequence from which a subsequence will be
     *         appended.  If <tt>csq</tt> is <tt>null</tt>, then characters
     *         will be appended as if <tt>csq</tt> contained the four
     *         characters <tt>"null"</tt>.
     *
     * @param  start
     *         The index of the first character in the subsequence
     *
     * @param  end
     *         The index of the character following the last character in the
     *         subsequence
     *
     * @return  This writer
     *
     * @throws  IndexOutOfBoundsException
     *          If <tt>start</tt> or <tt>end</tt> are negative, <tt>start</tt>
     *          is greater than <tt>end</tt>, or <tt>end</tt> is greater than
     *          <tt>csq.length()</tt>
     *
     * @since  1.5
     */
    public StringWriter append(CharSequence csq, int start, int end) {
        CharSequence cs = (csq == null ? "null" : csq);
        write(cs.subSequence(start, end).toString());
        return this;
    }

    
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) 


Params:
  • c – 
        The 16-bit character to append
Returns: This writer
Since:1.5
/**
     * Appends the specified character to this writer.
     *
     * <p> An invocation of this method of the form <tt>out.append(c)</tt>
     * behaves in exactly the same way as the invocation
     *
     * <pre>
     *     out.write(c) </pre>
     *
     * @param  c
     *         The 16-bit character to append
     *
     * @return  This writer
     *
     * @since 1.5
     */
    public StringWriter append(char c) {
        write(c);
        return this;
    }

    
Return the buffer's current value as a string.

/**
     * Return the buffer's current value as a string.
     */
    public String toString() {
        return buf.toString();
    }

    
Return the string buffer itself.

Returns:StringBuffer holding the current buffer value.
/**
     * Return the string buffer itself.
     *
     * @return StringBuffer holding the current buffer value.
     */
    public StringBuffer getBuffer() {
        return buf;
    }

    
Flush the stream.

/**
     * Flush the stream.
     */
    public void flush() {
    }

    
Closing a StringWriter has no effect. The methods in this
class can be called after the stream has been closed without generating
an IOException.

/**
     * Closing a <tt>StringWriter</tt> has no effect. The methods in this
     * class can be called after the stream has been closed without generating
     * an <tt>IOException</tt>.
     */
    public void close() throws IOException {
    }

}