subject:"Extend"

Re: Why can I not extend java.util.Date?

2016-03-24 Thread Thomas Broyer



On Thursday, March 24, 2016 at 2:25:09 PM UTC+1, Stefan Falk wrote:
>
> My main problem here is that on the server side everything is following 
> the ISO standard MONDAY = 1, TUESDAY = 2, .. etc and since we only got Date 
> on he client things can get mixed up. This is why I thought I could 
> wrap/extend Date and just override the getDay() method in order to
>
>- have the mapping exactly where I need it and
>
>
You're breaking the Liskov substitution principle. This is not good OOP, 
don't do it.


>- get rid of all the deprecation warnings in my code as I use only 
>MyDate
>
> How about using a MyDate that can do whatever you want it to do by 
wrapping a JsDate or Date (or just a double), possibly providing a toDate() 
returning a java.util.Date for those places where you need it (formatting, 
etc.)
That MyDate can still be serializable (assuming your problem here is 
GWT-RPC serialization), either directly (if wrapping a Date or double) or 
through a CustomFieldSerializer.

Or you could *add* a new method to your subclass to avoid changing the 
java.util.Date contract. As for GWT-RPC serialization, if extending 
java.util.Date, you'll have to provide a CustomFieldSerializer (just copy 
the 
com.google.gwt.user.client.rpc.core.java.util.Date_CustomFieldSerializer 
and use your own class instead)

Speaking of Date .. will there actually be support for all of the fancy 
> Date/Time stuff that came with Java 8? Again, like you said, working with 
> Dates is very hard sometimes so imho it would be very important to get 
> there with GWT. But I understand that this might also not be that easy and 
> it must have a particular reason why it's not yet there.
>

Reason number 1 is “it's a whole lot of work”.
I suppose ThreeTen or ThreeTenBP can be used as a starting point (friendly 
licensing), but there'd still be a lot of code that'd need to be deleted 
and/or adapted.
It's more important to get java.util.function and java.util.stream in 
(ongoing work) than java.time.

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Re: Why can I not extend java.util.Date?

2016-03-24 Thread Chad Vincent

If you do extend Date, I would not use any 3rd party library calls that 
take a Date and may use Day of Week, as they might well explode on Sundays. 
 And that has the same problem as a util class, you may forget and make the 
call somewhere.  It's really a lose-lose situation.

You're not really saying what you're doing with the ISO DOW, but you do 
know that SimpleDateFormat supports the ISO enumeration, right?  Looks like 
"u" is the Monday = 1, Sunday = 7 version, though "F" may also work.

As for the Java 8 java.time support, it appears it is planned but not yet 
in-progress: https://github.com/gwtproject/gwt/issues/611

On Thursday, March 24, 2016 at 8:25:09 AM UTC-5, Stefan Falk wrote:
>
> My main problem here is that on the server side everything is following 
> the ISO standard MONDAY = 1, TUESDAY = 2, .. etc and since we only got Date 
> on he client things can get mixed up. This is why I thought I could 
> wrap/extend Date and just override the getDay() method in order to
>
>- have the mapping exactly where I need it and
>- get rid of all the deprecation warnings in my code as I use only 
>MyDate
>
> I agree with you.. Dates are very hard to handle and I really hate it 
> actually ^^ That is even more a reason for me to get things straight with 
> my client and server. Having to call another method from another util class 
> is also just not what I am looking for - it can also be forgotten somewhere.
>
> Speaking of Date .. will there actually be support for all of the fancy 
> Date/Time stuff that came with Java 8? Again, like you said, working with 
> Dates is very hard sometimes so imho it would be very important to get 
> there with GWT. But I understand that this might also not be that easy and 
> it must have a particular reason why it's not yet there.
>
>
>
>
> On Tuesday, 22 March 2016 16:01:11 UTC+1, Chad Vincent wrote:
>>
>> 1) Dates are very, very, very hard.  Calendar idiosyncrasies, time zones, 
>> leap seconds...  Be 100% sure you need to actually extend Date before 
>> messing with it.
>> 2) You are probably better off putting your method (presuming this is the 
>> only one) in a custom utility class instead of extending Date so you don't 
>> alter the functionality of any other libraries you use that aren't 
>> expecting DOW to be non-standard.
>> getCustomDay(Date date) {
>>   if (date.getDay() == 0)
>> return 7;
>>   return date.getDay();
>> }
>>
>>
>>
>> On Sunday, March 20, 2016 at 12:24:09 PM UTC-5, Stefan Falk wrote:
>>>
>>> Working with Date is a nightmare.. so beforehand: Any advice regarding 
>>> work with time and date in GWT are very welcome!
>>>
>>> Why do my requests silently fail if I do this:
>>>
>>> public class AwesomeDate extends java.util.Date {
>>>
>>>   public final static int MONDAY = 1; 
>>>   public final static int TUESDAY = 2; 
>>>   public final static int WEDNESDAY = 3; 
>>>   public final static int THURSDAY = 4; 
>>>   public final static int FRIDAY = 5; 
>>>   public final static int SATURDAY = 6; 
>>>   public final static int SUNDAY = 7;
>>>
>>>   @Override
>>>   public int getDay() { 
>>> switch(super.getDay()) { 
>>> case 1:
>>>   return MONDAY;
>>> case 2:
>>>   return TUESDAY;
>>> case 3:
>>>   return WEDNESDAY;
>>> case 4:
>>>   return THURSDAY;
>>> case 5:
>>>   return FRIDAY;
>>> case 6:
>>> return SATURDAY;
>>>   case 0:
>>>   return SUNDAY;
>>> } 
>>> throw new RuntimeException();
>>>   }
>>> }
>>>
>>>
>>> and then
>>>
>>> AwesomeDate fromDate = ..
>>> AwesomeDate toDate = ..
>>>
>>> myObjectEnter.request(fromDate, toDate, onSuccess, onFailure);
>>>
>>>
>>> where
>>>
>>> MyObject#request(Date from, Date to, OnSuccess success, 
>>> OnFailure failure);
>>>
>>>
>>> Because if I do that my request does simply nothing. It's not even 
>>> getting sent off.. I have an object that takes care for parallel requests
>>>
>>>  for (ParallelizableRequest parallelizableRequest : this.
>>> childRequests) {
>>>parallelizableRequest.request();
>>>  }
>>>
>>> but that request that is using AwesomeDate is simply not being executed. 
>>> In the JavaScript debugger I see that the list childRequests contains two 
>>> elements but that's all I can tell.
>>>
>>> Any ideas?
>>>
>>

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Re: Why can I not extend java.util.Date?

2016-03-24 Thread Stefan Falk

My main problem here is that on the server side everything is following the 
ISO standard MONDAY = 1, TUESDAY = 2, .. etc and since we only got Date on 
he client things can get mixed up. This is why I thought I could 
wrap/extend Date and just override the getDay() method in order to

   - have the mapping exactly where I need it and
   - get rid of all the deprecation warnings in my code as I use only MyDate

I agree with you.. Dates are very hard to handle and I really hate it 
actually ^^ That is even more a reason for me to get things straight with 
my client and server. Having to call another method from another util class 
is also just not what I am looking for - it can also be forgotten somewhere.

Speaking of Date .. will there actually be support for all of the fancy 
Date/Time stuff that came with Java 8? Again, like you said, working with 
Dates is very hard sometimes so imho it would be very important to get 
there with GWT. But I understand that this might also not be that easy and 
it must have a particular reason why it's not yet there.




On Tuesday, 22 March 2016 16:01:11 UTC+1, Chad Vincent wrote:
>
> 1) Dates are very, very, very hard.  Calendar idiosyncrasies, time zones, 
> leap seconds...  Be 100% sure you need to actually extend Date before 
> messing with it.
> 2) You are probably better off putting your method (presuming this is the 
> only one) in a custom utility class instead of extending Date so you don't 
> alter the functionality of any other libraries you use that aren't 
> expecting DOW to be non-standard.
> getCustomDay(Date date) {
>   if (date.getDay() == 0)
> return 7;
>   return date.getDay();
> }
>
>
>
> On Sunday, March 20, 2016 at 12:24:09 PM UTC-5, Stefan Falk wrote:
>>
>> Working with Date is a nightmare.. so beforehand: Any advice regarding 
>> work with time and date in GWT are very welcome!
>>
>> Why do my requests silently fail if I do this:
>>
>> public class AwesomeDate extends java.util.Date {
>>
>>   public final static int MONDAY = 1; 
>>   public final static int TUESDAY = 2; 
>>   public final static int WEDNESDAY = 3; 
>>   public final static int THURSDAY = 4; 
>>   public final static int FRIDAY = 5; 
>>   public final static int SATURDAY = 6; 
>>   public final static int SUNDAY = 7;
>>
>>   @Override
>>   public int getDay() { 
>> switch(super.getDay()) { 
>> case 1:
>>   return MONDAY;
>> case 2:
>>   return TUESDAY;
>> case 3:
>>   return WEDNESDAY;
>> case 4:
>>   return THURSDAY;
>> case 5:
>>   return FRIDAY;
>> case 6:
>> return SATURDAY;
>>   case 0:
>>   return SUNDAY;
>> } 
>> throw new RuntimeException();
>>   }
>> }
>>
>>
>> and then
>>
>> AwesomeDate fromDate = ..
>> AwesomeDate toDate = ..
>>
>> myObjectEnter.request(fromDate, toDate, onSuccess, onFailure);
>>
>>
>> where
>>
>> MyObject#request(Date from, Date to, OnSuccess success, 
>> OnFailure failure);
>>
>>
>> Because if I do that my request does simply nothing. It's not even 
>> getting sent off.. I have an object that takes care for parallel requests
>>
>>  for (ParallelizableRequest parallelizableRequest : this.childRequests
>> ) {
>>parallelizableRequest.request();
>>  }
>>
>> but that request that is using AwesomeDate is simply not being executed. 
>> In the JavaScript debugger I see that the list childRequests contains two 
>> elements but that's all I can tell.
>>
>> Any ideas?
>>
>

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Re: Why can I not extend java.util.Date?

2016-03-22 Thread Chad Vincent

1) Dates are very, very, very hard.  Calendar idiosyncrasies, time zones, 
leap seconds...  Be 100% sure you need to actually extend Date before 
messing with it.
2) You are probably better off putting your method (presuming this is the 
only one) in a custom utility class instead of extending Date so you don't 
alter the functionality of any other libraries you use that aren't 
expecting DOW to be non-standard.
getCustomDay(Date date) {
  if (date.getDay() == 0)
return 7;
  return date.getDay();
}



On Sunday, March 20, 2016 at 12:24:09 PM UTC-5, Stefan Falk wrote:
>
> Working with Date is a nightmare.. so beforehand: Any advice regarding 
> work with time and date in GWT are very welcome!
>
> Why do my requests silently fail if I do this:
>
> public class AwesomeDate extends java.util.Date {
>
>   public final static int MONDAY = 1; 
>   public final static int TUESDAY = 2; 
>   public final static int WEDNESDAY = 3; 
>   public final static int THURSDAY = 4; 
>   public final static int FRIDAY = 5; 
>   public final static int SATURDAY = 6; 
>   public final static int SUNDAY = 7;
>
>   @Override
>   public int getDay() { 
> switch(super.getDay()) { 
> case 1:
>   return MONDAY;
> case 2:
>   return TUESDAY;
> case 3:
>   return WEDNESDAY;
> case 4:
>   return THURSDAY;
> case 5:
>   return FRIDAY;
> case 6:
> return SATURDAY;
>   case 0:
>   return SUNDAY;
> } 
> throw new RuntimeException();
>   }
> }
>
>
> and then
>
> AwesomeDate fromDate = ..
> AwesomeDate toDate = ..
>
> myObjectEnter.request(fromDate, toDate, onSuccess, onFailure);
>
>
> where
>
> MyObject#request(Date from, Date to, OnSuccess success, 
> OnFailure failure);
>
>
> Because if I do that my request does simply nothing. It's not even getting 
> sent off.. I have an object that takes care for parallel requests
>
>  for (ParallelizableRequest parallelizableRequest : this.childRequests) 
> {
>parallelizableRequest.request();
>  }
>
> but that request that is using AwesomeDate is simply not being executed. 
> In the JavaScript debugger I see that the list childRequests contains two 
> elements but that's all I can tell.
>
> Any ideas?
>

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Why can I not extend java.util.Date?

2016-03-20 Thread Stefan Falk

Working with Date is a nightmare.. so beforehand: Any advice regarding work 
with time and date in GWT are very welcome!

Why do my requests silently fail if I do this:

public class AwesomeDate extends java.util.Date {

  public final static int MONDAY = 1; 
  public final static int TUESDAY = 2; 
  public final static int WEDNESDAY = 3; 
  public final static int THURSDAY = 4; 
  public final static int FRIDAY = 5; 
  public final static int SATURDAY = 6; 
  public final static int SUNDAY = 7;

  @Override
  public int getDay() { 
switch(super.getDay()) { 
case 1:
  return MONDAY;
case 2:
  return TUESDAY;
case 3:
  return WEDNESDAY;
case 4:
  return THURSDAY;
case 5:
  return FRIDAY;
case 6:
return SATURDAY;
  case 0:
  return SUNDAY;
} 
throw new RuntimeException();
  }
}


and then

AwesomeDate fromDate = ..
AwesomeDate toDate = ..

myObjectEnter.request(fromDate, toDate, onSuccess, onFailure);


where

MyObject#request(Date from, Date to, OnSuccess success, 
OnFailure failure);


Because if I do that my request does simply nothing. It's not even getting 
sent off.. I have an object that takes care for parallel requests

 for (ParallelizableRequest parallelizableRequest : this.childRequests) {
   parallelizableRequest.request();
 }

but that request that is using AwesomeDate is simply not being executed. In 
the JavaScript debugger I see that the list childRequests contains two 
elements but that's all I can tell.

Any ideas?

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DTD factory class org.apache.xerces.impl.dv.dtd.DTDDVFactoryImpl does not extend from DTDDVFactory after using GWT's XML parser

2014-10-14 Thread Petros Petrosyan

I have an application which uses xml parser library - XOM ( www.xom.nu ).
The parser works without any issues until I do parsing on GWT side via

com.google.gwt.xml.client.XMLParser.

After the parsing is done on GWT client side, when I try to do another
parsing with XOM, I get the following exception:

org.apache.xerces.impl.dv.DVFactoryException: *DTD factory **class
org.apache.xerces.impl.dv.dtd.DTDDVFactoryImpl does not extend from
DTDDVFactory.*
at org.apache.xerces.impl.dv.DTDDVFactory.getInstance(Unknown Source)

at org.apache.xerces.impl.dv.DTDDVFactory.getInstance(Unknown Source)

at org.apache.xerces.parsers.DTDConfiguration.createDatatypeValidatorFactory
(Unknown Source)

at org.apache.xerces.parsers.DTDConfiguration.(Unknown Source)

at nu.xom.XML1_0Parser.(Unknown Source)

at nu.xom.Builder.findParser(Unknown Source)

at nu.xom.Builder.(Unknown Source)

at XMLParser.tryParse(XMLParser.java:42)

I have googled this issue and found different suggestions ( including
http://stackoverflow.com/questions/4730103/xerces-error-org-apache-xerces-impl-dv-dtd-dtddvfactoryimpl)

, however none of them helped me.

What I found is that gwt-dev.jar and XOM they both use Xerces, so when
gwt-dev.jar uses Xerces, the DTD class somehow changes and afterwards XOM's
Xerces instance does not recognize the DVFactoryException as it is from
another package.

I also tried to use the java.endorsed.dirs but it didn't help.

Has anyone had similar issue? If so, please give me hint what is going on
here.

Thanks,

Petros

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