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我想在Objectify4的新功能利用然而我的應用程序是建立並正在與版本3.我的應用程序在很大程度上建立在ObjectifyGenericDao模式，而且Objectify4設計模式是從這個非常不同：ObjectifyGenericDao <T>與Objectify4
ObjectifyGenericDao.java
public class ObjectifyGenericDao<T> extends DAOBase
{
static final int BAD_MODIFIERS = Modifier.FINAL | Modifier.STATIC | Modifier.TRANSIENT;
static
{
// Register all your entity classes here
}
protected Class<T> clazz;
/**
* We've got to get the associated domain class somehow
*
* @param clazz
*/
protected ObjectifyGenericDao(Class<T> clazz)
{
this.clazz = clazz;
}
public ObjectifyGenericDao(ObjectifyOpts opts) {
super(opts);
//this.clazz = clazz;
}
public Key<T> put(T entity)
{
return ofy().put(entity);
}
// TODO This code was modified
// and need to be tested
public List<Key<T>> putAll(Iterable<T> entities)
{
Map<Key<T>, T> map = ofy().put(entities);
return new ArrayList<Key<T>>(map.keySet());
//return ofy().put(entities);
}
public void delete(T entity)
{
ofy().delete(entity);
}
public void deleteKey(Key<T> entityKey)
{
ofy().delete(entityKey);
}
public void deleteAll(Iterable<T> entities)
{
ofy().delete(entities);
}
public void deleteKeys(Iterable<Key<T>> keys)
{
ofy().delete(keys);
}
public T get(Long id) throws EntityNotFoundException
{
return ofy().get(this.clazz, id);
}
public T get(String id) throws EntityNotFoundException
{
return ofy().get(this.clazz, id);
}
public T get(Key<T> key) throws EntityNotFoundException
{
return ofy().get(key);
}
/**
* Convenience method to get all objects matching a single property
*
* @param propName
* @param propValue
* @return T matching Object
*/
public T getByProperty(String propName, Object propValue)
{
Query<T> q = ofy().query(clazz);
q.filter(propName, propValue);
return q.get();
}
public List<T> listByProperty(String propName, Object propValue)
{
Query<T> q = ofy().query(clazz);
q.filter(propName, propValue);
return asList(q.fetch());
}
public List<Key<T>> listKeysByProperty(String propName, Object propValue)
{
Query<T> q = ofy().query(clazz);
q.filter(propName, propValue);
return asKeyList(q.fetchKeys());
}
public T getByExample(T exampleObj)
{
Query<T> queryByExample = buildQueryByExample(exampleObj);
Iterable<T> iterableResults = queryByExample.fetch();
Iterator<T> i = iterableResults.iterator();
T obj = i.next();
if (i.hasNext())
throw new RuntimeException("Too many results");
return obj;
}
public List<T> listByExample(T exampleObj)
{
Query<T> queryByExample = buildQueryByExample(exampleObj);
return asList(queryByExample.fetch());
}
private List<T> asList(Iterable<T> iterable)
{
ArrayList<T> list = new ArrayList<T>();
for (T t : iterable)
{
list.add(t);
}
return list;
}
private List<Key<T>> asKeyList(Iterable<Key<T>> iterableKeys)
{
ArrayList<Key<T>> keys = new ArrayList<Key<T>>();
for (Key<T> key : iterableKeys)
{
keys.add(key);
}
return keys;
}
private Query<T> buildQueryByExample(T exampleObj)
{
Query<T> q = ofy().query(clazz);
// Add all non-null properties to query filter
for (Field field : clazz.getDeclaredFields())
{
// Ignore transient, embedded, array, and collection properties
if (field.isAnnotationPresent(Transient.class)
|| (field.isAnnotationPresent(Embedded.class))
|| (field.getType().isArray())
|| (Collection.class.isAssignableFrom(field.getType()))
|| ((field.getModifiers() & BAD_MODIFIERS) != 0))
continue;
field.setAccessible(true);
Object value;
try
{
value = field.get(exampleObj);
}
catch (IllegalArgumentException e)
{
throw new RuntimeException(e);
}
catch (IllegalAccessException e)
{
throw new RuntimeException(e);
}
if (value != null)
{
q.filter(field.getName(), value);
}
}
return q;
}
// Added, but may not be really useful
public Query<T> query(String filter, String value) {
Query<T> q = ofy().query(clazz).filter(filter, value);
return q;
}
與Objectify4的瓶頸是，它並沒有DAOBase所以它不是很容易遷移現有的代碼。
如何在使用Objectify4功能時使用此模式？