Apple

On Feb 5, 2015, at 4:51 PM, David Avendasora <email@hidden> wrote:

On Feb 5, 2015, at 1:38 PM, Theodore Petrosky <email@hidden> wrote:

David,

I am deliberately not responding to the list. Would you be interested in helping me get my head around this? If yes, what I can do, is when we are complete with this part, I will document it and submit it to the wiki docs.

What do you think, I can create a concrete example. The goal would be to add the static EOQualifier methods and create the rules that access them.’

I help with what I can. I’m pretty busy, but qualifiers are kinda my thing. :-)

I would really like it if you also posted this to the list as that is where a lot of people search.

like this guy a static method on Person:

Person <->> PersonInstrument <<-> Instrument <->> InstrumentBook <<-> Book

Then:
public static synchronized EOQualifier thatAreForPersonByInstrument(Person person) {
return Book.INSTRUMENT_BOOKS.containsAnyObjectSatisfying(
InstrumentBook.INSTRUMENT.dot(
Instrument.PERSON_INSTRUMENTS.containsAnyObjectSatisfying(
PersonInstrument.PERSON.is( person ) ) ) );
}

how would you create a rule to access use this.

When I’ve done D2W stuff where I don’t want the full list of values for a relationship, I used the “restrictedChoiceKey"

90 : ((pageConfiguration like 'Create*' or pageConfiguration like 'Edit*') and (propertyKey = 'book')) => restrictedChoiceKey = "object.availableBooks" [com.webobjects.directtoweb.Assignment]

You specify the regular relationship key of the relationship you want to set in this case "(propertyKey = 'book’)" , but set the rule’s key to "restrictedChoiceKey” and point it to a different keypath that contains the qualified (and sorted, if needed) list of valid values, in this case “object.availableBooks”. (the “object” in the binding keypath just means to look on the same object that the “propertyKey” binding is for.

In the code below, I’m assuming “Person” is also the class that has the “book” propertyKey, if it isn’t you’ll just have to change how you get the person object.

The method would look something like this:

public NSArray<Book> availableBooks() {
NSArray<Book> allBooks = [however you get the list of all books from the DB];
EOQualifier thatAreAvailableToPerson = Book.thatAreForPersonByInstrument(this);
MSArray<Book> availableBooks = ERXQ.filtered(allBooks, thatAreAvailableToPerson);
return availableBooks;
}

That’s really about it.

I hope this helps, and please do post this back to the list in some form!

Dave

Ted

On Feb 5, 2015, at 9:09 AM, David Avendasora <email@hidden> wrote:

ERXExistsQualifier to the rescue!

On Jan 29, 2015, at 9:12 AM, Theodore Petrosky <email@hidden> wrote:

The Person has an instrument. The Book has an instrument. so the popup list should be only those books with the same instrument.

To match instances of book that are for an instrument that is related to a given person:

If this is your model:
Person <<-> Instrument <->> Book

Then:
public static synchronized EOQualifier thatAreForPersonByInstrument(Person person) {
return Book.INSTRUMENT.dot(Instrument.PERSONS.containsAnyObjectSatisfying( person ) );
}

OR If this is your model (seems more likely):

Person <->> PersonInstrument <<-> Instrument <->> InstrumentBook <<-> Book

Then:
public static synchronized EOQualifier thatAreForPersonByInstrument(Person person) {
return Book.INSTRUMENT_BOOKS.containsAnyObjectSatisfying(
InstrumentBook.INSTRUMENT.dot(
Instrument.PERSON_INSTRUMENTS.containsAnyObjectSatisfying(
PersonInstrument.PERSON.is( person ) ) ) );
}

But one layer deeper. a Person is assigned to one or many Shows. the Books belong to a show. So if Person 1 only play one show and plays viola (I know its a handicapped Person), the popup list only shows that one book as available to assign.

Person <->> ShowPerson <<-> Show <->> Book

public static synchronized EOQualifier thatAreForPersonByShow(Person person) {
return Book.SHOW.dot(
Show.SHOW_PERSON.containsAnyObjectSatisfying(
ShowPerson.PERSON.is( person ) ) );
}

And to combine them together:

public static synchronized EOQualifier thatAreForPerson(Person person) {
return Book.thatAreForPersonByInstrument( person )
.and( thatAreForPersonByShow( person ) );
}

By making these static methods, not only can you use that in your fetch specification, but you can also use it to check to see if a book is available to a person (for example, in validateForSave, or wherever else):

public boolean isVisibleTo(Person person) {
return thatAreForPerson(person).evaluateWithObject(this);
}

Dave

—————————————————————————————
WebObjects - so easy that even Dave Avendasora can do it!™
—————————————————————————————
David Avendasora
Senior Software Abuser
Nekesto, Inc.

—————————————————————————————
WebObjects - so easy that even Dave Avendasora can do it!™
—————————————————————————————
David Avendasora
Senior Software Abuser
Nekesto, Inc.

References:
	>Re: limiting popupbutton list with a fetchSpec (From: David Avendasora <email@hidden>)