[TAP5-2389] [tapestry-jpa] Better EntityPersistentFieldStrategy that can persist transient entity

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 5.4
• Component/s: tapestry-jpa
• Labels: jpa
• Assignee: Unassigned
• Reporter: Charles Capon
• Created: 18/Sep/14 13:31
• Updated: 06/Nov/14 09:38

Description

I'm using tapestry-jpa and I want to persist an entity that can be transient or not in a component.

There is an issue with transient entities because they can not be persisted without an exception to be raised.

Here is a code of a better EntityPersistentFieldStrategy that can persist transient and managed entity

EntityPersistentFieldStrategy.java

public class EntityPersistentFieldStrategy extends AbstractSessionPersistentFieldStrategy {

    private final static String PREFIX = "entity:";

    private final EntityManagerManager entityManagerManager;

    public EntityPersistentFieldStrategy(final EntityManagerManager entityManagerManager,
            final Request request) {
        super(PREFIX, request);
        this.entityManagerManager = entityManagerManager;
    }

    @Override
    protected Object convertApplicationValueToPersisted(final Object newValue) {
        try {
            return JpaInternalUtils.convertApplicationValueToPersisted(entityManagerManager,
                    newValue);
        } catch (final RuntimeException ex) {
            return super.convertApplicationValueToPersisted(newValue);
        }
    }

    @Override
    protected Object convertPersistedToApplicationValue(final Object persistedValue) {
        if (persistedValue instanceof PersistedEntity) {
            final PersistedEntity persisted = (PersistedEntity) persistedValue;

            return persisted.restore(entityManagerManager);
        } else {
            return super.convertPersistedToApplicationValue(persistedValue);
        }
    }
}