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Thread: Comparing Two Dates

  1. #1
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    Default Comparing Two Dates

    Ok, so I'm ripping my hair out over this.

    I have two 3 GregorianCalendar objects. Due to reasons unknown, the .after() and .before() methods are not working correctly all the time, so I'm having to make a method my own to get some sort of consistency.

    Basically, I'm just wanting to check if a Date is between (inclusively) a range of dates.

    After trying a bunch of different things (all with complete failure), I tried to make the most concise set of conditional statements I could. But, it still doesn't work. Can anyone find the logic problem in this?

    public boolean withinTimeFrame(GregorianCalendar g)
    	{
    		int year = g.get(GregorianCalendar.YEAR);
    		int month = g.get(GregorianCalendar.MONTH);
    		int day = g.get(GregorianCalendar.DAY_OF_MONTH);
    		int yearS = StartDate.get(GregorianCalendar.YEAR);
    		int monthS = StartDate.get(GregorianCalendar.MONTH);
    		int dayS = StartDate.get(GregorianCalendar.DAY_OF_MONTH);
    		int yearE = EndDate.get(GregorianCalendar.YEAR);
    		int monthE = EndDate.get(GregorianCalendar.MONTH);
    		int dayE = EndDate.get(GregorianCalendar.DAY_OF_MONTH);
     
    		if((year==yearS && month==monthS && day==dayS)||(year==yearE && month==monthE && day==dayE))
    			return true;
    		if(year>yearS)
    		{
    			if(year<yearE)
    				return true;
    			else if(year==yearE)
    			{
    				if(month<monthE)
    					return true;
    				else if(month==monthE)
    				{
    					if(day<=dayE)
    						return true;
    					else
    						return false;
    				}
    				else
    					return false;
    			}
    			else
    				return false;
    		}
    		else if(year==yearS)
    		{
    			if(year<yearE)
    				return true;
    			else if(year==yearE)
    			{
    				if(month>monthS)
    				{
    					if(month<monthE)
    						return true;
    					else if(month==monthE)
    					{
    						if(day<=dayE)
    							return true;
    						else
    							return false;
    					}
    					else
    						return false;
    				}
    				else if(month==monthS)
    				{
    					if(day>dayS)
    					{
    						if(month<monthE)
    							return true;
    						else if(month==monthE)
    						{
    							if(day<=dayE)
    								return true;
    							else
    								return false;
    						}
    						else
    							return false;
    					}
    					else if(day==dayS)
    						return true;
    					else
    						return false;
    				}
    				else
    					return false;
    			}
    			else
    				return false;
    		}
    		else
    			return false;
    	}

    For example, if I have the following 2 inputs:
    Input 1:
    StartDate = September 7, 2011
    EndDate = November 7, 2011
    g = October 6, 2011
    Input 2:
    StartDate = September 7, 2011
    EndDate = November 7, 2011
    g = November 4, 2011


    So, if g is between (inclusively) StartDate and EndDate, the method should return true. Otherwise, it should return false.

    At the moment, I know at least one of these (if not both) is returning true. I'm attempting to isolate the problem.


    EDIT:
    It is returning false for both inputs.
    Last edited by aussiemcgr; June 27th, 2011 at 11:17 AM. Reason: More information
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  2. #2
    Super Moderator Norm's Avatar
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    Default Re: Comparing Two Dates

    Could you use this value: time as UTC milliseconds from the epoch
    A long value for the three dates and then just compare them.

  3. #3
    Administrator copeg's Avatar
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    Default Re: Comparing Two Dates

    As Norm suggested, just get the time in milliseconds (Calendar.getTimeInMillis() - the Date class has a similar method) and compare the returned long value. Seems a much easier alternative

  4. #4
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    Default Re: Comparing Two Dates

    This was actually my fault, not the code's. I was checking one direction, but not the other.

    For example, if you had two date ranges:
    Oct 5, 2011 to Dec 10, 2011
    Nov 1, 2011 to Nov 10, 2011

    The first would not conflict with the second, but the second would conflict with the first. I needed the second to conflict with the first AND the first to conflict with the second. I have it working as far as I know.
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    2. Give full details of errors and provide us with as much information about the situation as possible.
    3. Give us an example of what the output should look like when done correctly.

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