/**
 * Error-preserving writer.
 *
 * <p>This is needed to work around the problem that {@link PrintWriter} throws
 * away error information.  It can be interposed between a real {@link Writer}
 * and the surrounding formatting class to allow exceptions from the former to
 * be retrieved even if the latter doesn't expose them.
 */
class ReliableWriter extends Writer {
  /** Contained writer. */
  private Writer child;

  /** Last reported error. */
  private IOException error;

  /**
   * Construct a new reliable writer.
   *
   * @param child Writer to wrap
   */
  ReliableWriter(Writer child) {
    this.child = child;
  }

  /**
   * Get the last error.
   *
   * @return The last error thrown by the wrapped writer
   */
  public IOException getError() {
    return error;
  }

  public void close() throws IOException {
    try {
      child.close();
    } catch(IOException e) {
      error = e;
      throw(e);
    }
  }

  public void flush() throws IOException {
    try {
      child.flush();
    } catch(IOException e) {
      error = e;
      throw(e);
    }
  }

  public void write(char[] cbuf) throws IOException {
    try {
      child.write(cbuf);
    } catch(IOException e) {
      error = e;
      throw(e);
    }
  }

  public void write(char[] cbuf, int off, int len) throws IOException {
    try {
      child.write(cbuf, off, len);
    } catch(IOException e) {
      error = e;
      throw(e);
    }
  }

  public void write(int c) throws IOException {
    try {
      child.write(c);
    } catch(IOException e) {
      error = e;
      throw(e);
    }
  }

  public void write(String str) throws IOException {
    try {
      child.write(str);
    } catch(IOException e) {
      error = e;
      throw(e);
    }
  }

  public void write(String str, int off, int len) throws IOException {
    try {
      child.write(str, off, len);
    } catch(IOException e) {
      error = e;
      throw(e);
    }
  }
}