Java tutorial
/* * $Id: PdfNull.java 3759 2009-03-06 16:05:00Z blowagie $ * * Copyright 1999, 2000, 2001, 2002 Bruno Lowagie * * The contents of this file are subject to the Mozilla Public License Version 1.1 * (the "License"); you may not use this file except in compliance with the License. * You may obtain a copy of the License at http://www.mozilla.org/MPL/ * * Software distributed under the License is distributed on an "AS IS" basis, * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License * for the specific language governing rights and limitations under the License. * * The Original Code is 'iText, a free JAVA-PDF library'. * * The Initial Developer of the Original Code is Bruno Lowagie. Portions created by * the Initial Developer are Copyright (C) 1999, 2000, 2001, 2002 by Bruno Lowagie. * All Rights Reserved. * Co-Developer of the code is Paulo Soares. Portions created by the Co-Developer * are Copyright (C) 2000, 2001, 2002 by Paulo Soares. All Rights Reserved. * * Contributor(s): all the names of the contributors are added in the source code * where applicable. * * Alternatively, the contents of this file may be used under the terms of the * LGPL license (the "GNU LIBRARY GENERAL PUBLIC LICENSE"), in which case the * provisions of LGPL are applicable instead of those above. If you wish to * allow use of your version of this file only under the terms of the LGPL * License and not to allow others to use your version of this file under * the MPL, indicate your decision by deleting the provisions above and * replace them with the notice and other provisions required by the LGPL. * If you do not delete the provisions above, a recipient may use your version * of this file under either the MPL or the GNU LIBRARY GENERAL PUBLIC LICENSE. * * This library is free software; you can redistribute it and/or modify it * under the terms of the MPL as stated above or under the terms of the GNU * Library General Public License as published by the Free Software Foundation; * either version 2 of the License, or any later version. * * This library is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS * FOR A PARTICULAR PURPOSE. See the GNU Library general Public License for more * details. * * If you didn't download this code from the following link, you should check if * you aren't using an obsolete version: * http://www.lowagie.com/iText/ */ package com.lowagie.text.pdf; /** * <CODE>PdfNull</CODE> is the Null object represented by the keyword <VAR>null</VAR>. * <P> * This object is described in the 'Portable Document Format Reference Manual version 1.7' * section 3.2.8 (page 63). * * @see PdfObject */ public class PdfNull extends PdfObject { // CLASS CONSTANTS /** An instance of the <CODE>PdfNull</CODE>-object. */ public static final PdfNull PDFNULL = new PdfNull(); /** The content of the <CODE>PdfNull</CODE>-object. */ private static final String CONTENT = "null"; // CONSTRUCTOR /** * Constructs a <CODE>PdfNull</CODE>-object. * <P> * You never need to do this yourself, you can always use the static final object <VAR>PDFNULL</VAR>. */ public PdfNull() { super(NULL, CONTENT); } // CLASS METHOD public String toString() { return "null"; } }