pdfdate.java

一个java操作pdf文件的开发包,很好用的.

/*
 * $Id: PdfDate.java,v 1.23 2002/07/09 11:28:22 blowagie Exp $
 * $Name:  $
 *
 * 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;

import java.util.GregorianCalendar;

/**
 * <CODE>PdfDate</CODE> is the PDF date object.
 * <P>
 * PDF defines a standard date format. The PDF date format closely follows the format
 * defined by the international standard ASN.1 (Abstract Syntax Notation One, defined
 * in CCITT X.208 or ISO/IEC 8824). A date is a <CODE>PdfString</CODE> of the form:
 * <P><BLOCKQUOTE>
 * (D: YYYYMMDDHHmmSSOHH'mm')
 * </BLOCKQUOTE><P>
 * This object is described in the 'Portable Document Format Reference Manual version 1.3'
 * section 7.2 (page 183-184)
 *
 * @see		PdfString
 * @see		java.util.GregorianCalendar
 */

class PdfDate extends PdfString {
    
    // constructors
    
/**
 * Constructs a <CODE>PdfDate</CODE>-object.
 *
 * @param		d			the date that has to be turned into a <CODE>PdfDate</CODE>-object
 */
    
    PdfDate(GregorianCalendar d) {
        super();
        StringBuffer date = new StringBuffer("D:");
        date.append(setLength(d.get(GregorianCalendar.YEAR), 4));
        date.append(setLength(d.get(GregorianCalendar.MONTH) + 1, 2));
        date.append(setLength(d.get(GregorianCalendar.DATE), 2));
        date.append(setLength(d.get(GregorianCalendar.HOUR_OF_DAY), 2));
        date.append(setLength(d.get(GregorianCalendar.MINUTE), 2));
        date.append(setLength(d.get(GregorianCalendar.SECOND), 2));
        int timezone = d.get(GregorianCalendar.ZONE_OFFSET) / (60 * 60 * 1000);
        if (timezone == 0) {
            date.append("Z");
        }
        else if (timezone < 0) {
            date.append("-");
            timezone = -timezone;
        }
        else {
            date.append("+");
        }
        date.append(setLength(timezone, 2)).append("'");
        int zone = Math.abs(d.get(GregorianCalendar.ZONE_OFFSET) / (60 * 1000)) - (timezone * 60);
        date.append(setLength(zone, 2)).append("'");
        value = date.toString();
    }
    
/**
 * Constructs a <CODE>PdfDate</CODE>-object, representing the current day and time.
 */
    
    PdfDate() {
        this(new GregorianCalendar());
    }
    
/**
 * Adds a number of leading zeros to a given <CODE>String</CODE> in order to get a <CODE>String</CODE>
 * of a certain length.
 *
 * @param		i   		a given number
 * @param		length		the length of the resulting <CODE>String</CODE>
 * @return		the resulting <CODE>String</CODE>
 */
    
    private StringBuffer setLength(int i, int length) {
        StringBuffer tmp = new StringBuffer();
        tmp.append(i);
        while (tmp.length() < length) {
            tmp.insert(0, "0");
        }
        tmp.setLength(length);
        return tmp;
    }
}