I have a class Page with a variable List<IMG> images.
<code>
@PersistenceCapable(identityType = IdentityType.APPLICATION)
public class Page {
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
private Key key;
@Persistent
private final List<IMG> images;
...
}
</code>
My IMG class looks like this:
<code>
@PersistenceCapable(identityType = IdentityType.APPLICATION)
public class IMG {
...
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
private Key key;
...
}
</code>
I don't fully understand how the one to many key using
KeyFactory.Builder works. In order to make an instance of Page
persistent using the datastore, do I need to loop through every IMG
instance like this:
<code>
for(IMG image : images) {
KeyFactory.Builder keyBuilder = new KeyFactory.Builder
(Page.class.getSimpleName(), "page-id");
keyBuilder.addChild(IMG.class.getSimpleName(), image.getID());
Key key = keyBuilder.getKey();
image.setKey(key);
pm.makePersistent(image);
}
</code>
or can I do this?
<code>
KeyFactory.Builder keyBuilder = new KeyFactory.Builder
(Page.class.getSimpleName(), "page-id");
for(IMG image : images) {
keyBuilder.addChild(IMG.class.getSimpleName(), image.getID());
}
Key key = keyBuilder.getKey();
for(IMG image : images) {
image.setKey(key);
pm.makePersistent(image);
}
</code>
or can I just do this?
<code>
Page page;
...
Key key = KeyFactory.createKey(Page.class.getSimpleName(), page.getID
());
pm.makePersistent(page);
</code>
I never want to be able to access the IMG instances without the Page
instance, do I even need to give the IMG instances keys at all?
Thanks,
Finbarr
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