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