Add disable/enable calculation of items in group

[Gena928]

fixes #6042
This is my first Pull Request to a project (new Java developer).

Add: disable/enable calculation of items in group

I realized that GroupNodeViewModel.java class uses method "calculateNumberOfMatches" to get number of items. Looks like it uploads full database from disk every time you need to calculate No of items in group. Therefore, if you have 1 thousand groups, it will read the entire database 1 thousand times.

UI changes:

• added new checkbox in Preferences/Groups - "Display quantity of items in group";
• added new property DISPLAY_GROUP_QUANTITY to JabRefPreferences.java file;
• connected new checkbox with JabRefPreferences.java. I used another preferences as a sample;

Logic changes:

• I added link to JabRefPreferences in GroupTreeView class.
  If user wants to display groups quantity, a panel with quantity will be shown. Quantity is calculated when GroupNodeViewModel class is initialized, so I decided to wrap a panel into an "if" statement.

Tests passed.

[Siedlerchr]

Thanks for your contribution and thanks for investigating:

Looks like it uploads full database from disk every time you need to calculate No of items in group. Therefore, if you have 1 thousand groups, it will read the entire database 1 thousand times.

Could you add some details on this problem, so maybe we are able to fix the underlying issue as well

[Gena928]

Good day,

I was working on this issue: https://github.com/JabRef/jabref/issues/6042
It says JabRef starts slowly if you have a lot of groups. Proposed improvement: disable calculation of items quantity in group.

Kind regards,
Gennadiy

[tobiasdiez]

Looks good to me. Thanks for your contribution. Just one last remark before we can merge.

[tobiasdiez]

As noted in the issue, the circle node should always be displayed because it is also used for the any/all selected status. Can you thus please add the if check only around the text here.

[Gena928]

Done,
please see new GroupTreeeView.java. OK now?

[tobiasdiez]

Thanks for quick follow-up! Looks good indeed.

[tobiasdiez]

Oh, I was a bit quick with merging. Just saw that the code only influences the display of the hit number. But the cost intensive process is the actual calculation of this number, which still happens.

Could you please open a follow-up PR which makes sure that the calculation is also not done. Thanks.

jabref/src/main/java/org/jabref/gui/groups/GroupNodeViewModel.java

Lines 228 to 236 in b5d5ed0

	private void calculateNumberOfMatches() {
	// We calculate the new hit value
	// We could be more intelligent and try to figure out the new number of hits based on the entry change
	// for example, a previously matched entry gets removed -> hits = hits - 1
	BackgroundTask
	.wrap(() -> groupNode.calculateNumberOfMatches(databaseContext.getDatabase()))
	.onSuccess(hits::setValue)
	.executeWith(taskExecutor);
	}

[Gena928]

Hi,
sorry, my bad. I saw this last week, and forgot today in the morning. Would you mind, if I add PreferencesService to GroupNodeViewModel?
@Inject private PreferencesService preferencesService;

In this case my "if" statement goes from GroupTreeView to GroupNodeViewModel (calculateNumberOfMatches() method). Like this:

   private void calculateNumberOfMatches() {
       // We calculate the new hit value
       // We could be more intelligent and try to figure out the new number of hits based on the entry change
       // for example, a previously matched entry gets removed -> hits = hits - 1
       if (preferencesService.getDisplayGroupCount()) {
           BackgroundTask
                   .wrap(() -> groupNode.calculateNumberOfMatches(databaseContext.getDatabase()))
                   .onSuccess(hits::setValue)
                   .executeWith(taskExecutor);
       }
   }

OK?

[Gena928]

We can also remove CalculateNumberOfMatches() from GroupNodeViewModel constructor, and have 2 options:

Option No. 1

• insert CalculateNumberOfMatches() into getHits() method, before returning a value to GroupTreeView;

Options No. 2

• create a public method getHitsFromDatabase() (having CalculateNumberOfMatches inside) and call it from GroupTreeView, before calling getHits(). But only if count of if tems in groups is enabled.

[tobiasdiez]

I think the solution you proposed in #6233 (comment) is perfect!