package org.springextensions.db4o.support;
import org.springextensions.db4o.Db4oTemplate;
import org.springframework.dao.support.DaoSupport;
import org.springframework.util.Assert;
import com.db4o.ObjectContainer;
/**
* Convenient super class for Db4o data access objects.
*
* <p>
* Requires a ObjectContainer to be set, providing a Db4oTemplate based on it to
* subclasses. Can alternatively be initialized directly via a Db4oTemplate.
*
* <p>
* This class will create its own Db4oTemplate if only a ObjectContainer is
* passed in.
*
* @author Daniel Mitterdorfer
* @author Costin Leau
*
*/
public abstract class Db4oDaoSupport extends DaoSupport {
private Db4oTemplate template;
/**
* Set the Db4o ObjectContainer to be used by this DAO. Will automatically
* create a Db4oTemplate for the given ObjectContainer.
*
* @see #createDb4oTemplate
* @see #setDb4oTemplate
*/
public final void setObjectContainer(ObjectContainer container) {
template = createDb4oTemplate(container);
}
/**
* Create a Db4oTemplate for the given ObjectContainer. Only invoked if
* populating the DAO with a ObjectContainer reference!
* <p>
* Can be overridden in subclasses to provide a Db4oTemplate instance with
* different configuration, or a custom Db4oTemplate subclass.
*
* @param container the Db4o ObjectContainer to create a Db4oTemplate for
* @return the new Db4oTemplate instance
* @see #setObjectContainer
*/
protected Db4oTemplate createDb4oTemplate(ObjectContainer container) {
return new Db4oTemplate(container);
}
/**
* @return A valid object container if #setObjectContainer or #setTemplate
* have been invoked previously. This should ever be the case if you
* configure this class in your application context file and let Spring wire
* up the dependencies. If there was no previous call, null is returned.
*/
public final ObjectContainer getObjectContainer() {
return (template != null) ? template.getObjectContainer() : null;
}
/**
* Set the Db4oTemplate for this DAO explicitly, as an alternative to
* specifying an ObjectContainer.
*
* @see #setObjectContainer
*/
public final void setDb4oTemplate(Db4oTemplate db4oTemplate) {
template = db4oTemplate;
}
public final Db4oTemplate getDb4oTemplate() {
return template;
}
/**
* @see org.springframework.dao.support.DaoSupport#checkDaoConfig()
*/
protected final void checkDaoConfig() {
Assert.notNull(template, "objectContainer or db4oTemplate is required");
}
/**
* Convert the given db4o exception into a Spring unchecked DAO exception.
*
* @param ex
* @return
*/
protected final RuntimeException convertDb4oException(Exception ex) {
return template.convertDb4oAccessException(ex);
}
}