/*
 * This example is from the book "Java Foundation Classes in a Nutshell".
 * Written by David Flanagan. Copyright (c) 1999 by O'Reilly & Associates.  
 * You may distribute this source code for non-commercial purposes only.
 * You may study, modify, and use this example for any purpose, as long as
 * this notice is retained.  Note that this example is provided "as is",
 * WITHOUT WARRANTY of any kind either expressed or implied.
 */

import java.awt.*;
import java.awt.print.*;
import java.io.*;
import java.util.Vector;

public class PageableText implements Pageable, Printable {
  // Constants for font name, size, style and line spacing
  public static String FONTFAMILY = "Monospaced";
  public static int FONTSIZE = 10;
  public static int FONTSTYLE = Font.PLAIN;
  public static float LINESPACEFACTOR = 1.1f;

  PageFormat format;   // The page size, margins, and orientation
  Vector lines;        // The text to be printed, broken into lines
  Font font;           // The font to print with
  int linespacing;     // How much space between lines
  int linesPerPage;    // How many lines fit on a page
  int numPages;        // How many pages required to print all lines
  int baseline = -1;   // The baseline position of the font.

  /** Create a PageableText object for a string of text */
  public PageableText(String text, PageFormat format) throws IOException { 
    this(new StringReader(text), format); 
  }

  /** Create a PageableText object for a file of text */
  public PageableText(File file, PageFormat format) throws IOException { 
    this(new FileReader(file), format); 
  }

  /** Create a PageableText object for a stream of text */
  public PageableText(Reader stream, PageFormat format) throws IOException {
    this.format = format;

    // First, read all the text, breaking it into lines.
    // This code ignores tabs, and does not wrap long lines.
    BufferedReader in = new BufferedReader(stream);
    lines = new Vector();
    String line;
    while((line = in.readLine()) != null) 
      lines.addElement(line);

    // Create the font we will use, and compute spacing between lines
    font = new Font(FONTFAMILY, FONTSTYLE, FONTSIZE);
    linespacing = (int) (FONTSIZE * LINESPACEFACTOR);

    // Figure out how many lines per page, and how many pages
    linesPerPage = (int)Math.floor(format.getImageableHeight()/linespacing);
    numPages = (lines.size()-1)/linesPerPage + 1;
  }

  // These are the methods of the Pageable interface.
  // Note that the getPrintable() method returns this object, which means
  // that this class must also implement the Printable interface.
  public int getNumberOfPages() { return numPages; }
  public PageFormat getPageFormat(int pagenum) { return format; }
  public Printable getPrintable(int pagenum) { return this; }

  /**
   * This is the print() method of the Printable interface.
   * It does most of the printing work.
   */
  public int print(Graphics g, PageFormat format, int pagenum) {
    // Tell the PrinterJob if the page number is not a legal one.
    if ((pagenum < 0) | (pagenum >= numPages)) 
      return NO_SUCH_PAGE;

    // First time we're called, figure out the baseline for our font.
    // We couldn't do this earlier because we needed a Graphics object
    if (baseline == -1) {
      FontMetrics fm = g.getFontMetrics(font);
      baseline = fm.getAscent();
    }

    // Clear the background to white.  This shouldn't be necessary, but is
    // required on some systems to workaround an implementation bug
    g.setColor(Color.white);
    g.fillRect((int)format.getImageableX(), (int)format.getImageableY(),
               (int)format.getImageableWidth(), 
               (int)format.getImageableHeight());

    // Set the font and the color we will be drawing with.
    // Note that you cannot assume that black is the default color!
    g.setFont(font);
    g.setColor(Color.black);

    // Figure out which lines of text we will print on this page
    int startLine = pagenum * linesPerPage;
    int endLine = startLine + linesPerPage - 1;
    if (endLine >= lines.size()) 
      endLine = lines.size()-1;

    // Compute the position on the page of the first line.
    int x0 = (int) format.getImageableX();
    int y0 = (int) format.getImageableY() + baseline;

    // Loop through the lines, drawing them all to the page.
    for(int i=startLine; i <= endLine; i++) {
      // Get the line
      String line = (String)lines.elementAt(i);

      // Draw the line.
      // We use the integer version of drawString(), not the Java 2D
      // version that uses floating-point coordinates. A bug in early
      // Java2 implementations prevents the Java 2D version from working.
      if (line.length() > 0) 
        g.drawString(line, x0, y0);

      // Move down the page for the next line.
      y0 += linespacing;  
    }

    // Tell the PrinterJob that we successfully printed the page.
    return PAGE_EXISTS;
  }

  /**
   * This is a test program that demonstrates the use of PageableText
   */
  public static void main(String[] args) throws IOException, PrinterException {
    // Get the PrinterJob object that coordinates everything
    PrinterJob job = PrinterJob.getPrinterJob();

    // Get the default page format, then ask the user to customize it.
    PageFormat format = job.pageDialog(job.defaultPage());

    // Create our PageableText object, and tell the PrinterJob about it
    job.setPageable(new PageableText(new File(args[0]), format));

    // Ask the user to select a printer, etc., and if not canceled, print!
    if (job.printDialog()) 
      job.print();
  }
}