Java Date Value Check isValidDate(String date, String format)

Description

Tests the input string to ensure that a valid Date instance can be created from it according to the format provided.

License

Open Source License

Parameter

Parameter	Description
date	A date string.
format	Date format to conform to.

Return

True if it conforms to the specified date format; False otherwise.

Declaration

public static boolean isValidDate(String date, String format)

Method Source Code

//package com.java2s;
/*/* w  w w .ja  v  a2  s.c o m*/
 * CONFIDENTIAL AND PROPRIETARY SOURCE CODE OF
 * Institute of Systems Science, National University of Singapore
 *
 * Copyright 2012 Team 4(Part-Time), ISS, NUS, Singapore. All rights reserved.
 * Use of this source code is subjected to the terms of the applicable license
 * agreement.
 *
 * -----------------------------------------------------------------
 * REVISION HISTORY
 * -----------------------------------------------------------------
 * DATE             AUTHOR          REVISION      DESCRIPTION
 * 10 March 2012    Chen Changfeng   0.1            Class creating
 *                                        
 *                                        
 *                                        
 *                                        
 * 
 */

import java.text.SimpleDateFormat;
import java.util.*;

public class Main {
    private static String dateFormat = "dd/MM/yyyy";

    /**
     * Tests the input value to ensure that a valid Date instance can be created from it.
     * Roll over dates are not allowed here and will return a false value.
     * Eg. isValidDate(2002, 10, 32) will return false.
     * <p>
     * @param  year  The year value.
     * @param  month The month value. ( 1 - 12 )
     * @param  day   The day value. ( 1 - 31 )
     * @return True if all values can be used to create a single valid Date instance.
     */
    public static boolean isValidDate(int year, int month, int day) {

        if (day <= 0 || month <= 0 || year <= 0)
            return false;
        if (month > 12 || day > 31)
            return false;

        Calendar cal = Calendar.getInstance();
        cal.set(Calendar.YEAR, year);
        cal.set(Calendar.MONTH, month - 1);

        // Find the maximum field value possible for the day with the year and month.
        int maxDay = cal.getActualMaximum(Calendar.DAY_OF_MONTH);
        if (day > maxDay)
            return false;

        return true;
    }

    /**
     * Tests the input string to ensure that a valid Date instance can be created from it
     * according to the format provided.
     * <p>
     * @param  date   A date string.
     * @param  format Date format to conform to.
     * @return True if it conforms to the specified date format; False otherwise.
     */
    public static boolean isValidDate(String date, String format) {

        if (date == null)
            return false;

        try {
            parse(date, format);
        } catch (java.text.ParseException e) {
            return false;
        }
        return true;
    }

    /**
     * Tests the input string to ensure that a valid Date instance can be created
     * according to the date format specified in the System property.
     * <p>
     * If the properties file is not available or the dateformat property has
     * not been specified, the default format "dd/MM/yyyy" will be used.
     * <p>
     * @param  date A date string.
     * @return True if it conforms to the system date format; False otherwise.
     */
    public static boolean isValidDate(String date) {
        if (date == null)
            return false;

        try {
            parse(date);
        } catch (java.text.ParseException e) {
            return false;
        }

        return true;
    }

    /**
     * Returns a Date object instance from the input string.
     * The input string is parsed to return a date object based
     * on the date format specified in the System property.
     * <p>
     * @param  date The date string.
     * @return The date instance created.
     * @throws java.text.ParseException  - if the beginning of the specified string cannot be parsed.
     */
    public static Date parse(String date) throws java.text.ParseException {
        // Modified by Aris on 02/02/2009 for case 1296351
        //if ( date == null || date.length()==0) return null;
        if (date == null)
            return null;

        String dateformat = null;
        // Use the default format of "dd/MM/yyyy".
        dateformat = dateFormat;

        return parse(date, dateformat);
    }

    /**
     * Returns a Date object instance from the input string.
     * The input date string is parsed to return a date object
     * based on the format provided.
     * <p>
     * Eg., to parse the date string "01/01/2003 9:2 PM", use the
     * format "dd/MM/yyyy h:m a". The resultant data object will have
     * the value "Mar 11 2003 09:02", as displayed in 24 hr format.
     * <p>
     * @param  date   The date string.
     * @param  format The date format that the date string conforms to.
     * @return The date instance created.
     * @throws java.text.ParseException  - if the beginning of the specified string cannot be parsed.
     */
    public static Date parse(String date, String format)
            throws java.text.ParseException {
        SimpleDateFormat sdf = new SimpleDateFormat(format);
        sdf.setLenient(false);

        return sdf.parse(date);
    }
}