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Java > Open Source Codes > cayenne > tutorial > tapestry > pages > AddArtistPage


1 package cayenne.tutorial.tapestry.pages;
2
3 import org.apache.tapestry.IRequestCycle;
4 import org.apache.tapestry.event.PageEvent;
5 import org.objectstyle.cayenne.access.DataContext;
6
7 import cayenne.tutorial.tapestry.domain.Artist;
8
9 /**
10  * A page to create a new Artist and save him/her in the database.
11  *
12  * @author Eric Schneider
13  */
14 public abstract class AddArtistPage extends EditorPage {
15
16     // properties are defined as abstract setters and getters
17 // and are declared in AddArtistPage.page file
18 public abstract void setArtist(Artist value);
19     public abstract Artist getArtist();
20
21     public void saveArtistAction(IRequestCycle cycle) {
22         DataContext context = getVisitDataContext();
23
24         // obtain local reference to artist abstract property
25 Artist artist = getArtist();
26
27         if (!assertNotNull(artist.getArtistName())) {
28             appendHtmlToErrorMessage("You must provide a name.");
29         }
30
31         if (!assertNotNull(artist.getDateOfBirth())) {
32             appendHtmlToErrorMessage("You must provide a DOB.");
33         }
34
35         if (getHasErrorMessage()) {
36             return;
37         }
38
39         // since new artist wasn't registered, register it before save
40 context.registerNewObject(artist);
41
42         // commit to the database
43 context.commitChanges();
44
45         BrowseArtistsPage nextPage =
46             (BrowseArtistsPage) cycle.getPage("BrowseArtistsPage");
47
48         // update the next page if it has cached artists
49 // to avoid unneeded refetch
50 if (nextPage.getArtistList() != null) {
51             nextPage.getArtistList().add(artist);
52         }
53
54         cycle.activate(nextPage);
55     }
56
57     public void pageBeginRender(PageEvent event) {
58         // create new artist when page is initialized.
59 // Do not intsert it into DataContext just yet.
60 // Instead if we register it here, and the user abandons
61 // the page, we will have to find a way to rollback the context,
62 // to avoid grabage carried over to other pages
63 setArtist(new Artist());
64     }
65 }
66
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