// Copyright 2012 Citrix Systems, Inc. Licensed under the
// Apache License, Version 2.0 (the "License"); you may not use this
// file except in compliance with the License.  Citrix Systems, Inc.
// reserves all rights not expressly granted by the License.
// You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// 
// Automatically generated by addcopyright.py at 04/03/2012
package com.cloud.dao;

import java.io.Serializable;
import java.util.List;

import com.cloud.utils.db.GenericSearchBuilder;
import com.cloud.utils.db.SearchBuilder;
import com.cloud.utils.db.SearchCriteria;

/**
 * Generic Entity Manager to retrieve database objects.
 *
 */
public interface EntityManager {
    /**
     * Finds an entity by its id.
     * @param <T> class of the entity you're trying to find.
     * @param <K> class of the id that the entity uses.
     * @param entityType Type of the entity.
     * @param id id value
     * @return T if found; null if not.
     */
    public <T, K extends Serializable> T findById(Class<T> entityType, K id);
    
    /**
     * Finds an entity by external id which is always String
     * @param <T> entity class
     * @param entityType type of entity you're looking for.
     * @param xid external id
     * @return T if found, null if not.
     */
    public <T> T findByXid(Class<T> entityType, String xid);
    
    /**
     * Lists all entities.  Use this method at your own risk.
     * @param <T> entity class
     * @param entityType type of entity you're looking for.
     * @return List<T>
     */
    public <T> List<? extends T> list(Class<T> entityType);
    
    /**
     * Persists the entity.
     * @param <T> entity class
     * @param t entity
     * @return persisted entity.  Only use this after persisting.
     */
    public <T> T persist(T t);
    
    public <T> SearchBuilder<T> createSearchBuilder(Class<T> entityType);
    
    public <T, K> GenericSearchBuilder<T, K> createGenericSearchBuilder(Class<T> entityType, Class<K> resultType);
    
    public <T, K> List<K> search(Class<T> entityType, SearchCriteria<K> sc);
    
    public <T, K extends Serializable> void remove(Class<T> entityType, K id);
}