https://github.com/javaee/jpa-spec: Java(TM) Persistence API 
Copyright (c) 2008 - 2013 Oracle Corporation. All rights reserved.
This program and the accompanying materials are made available under the
terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
which accompanies this distribution.
The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
and the Eclipse Distribution License is available at
http://www.eclipse.org/org/documents/edl-v10.php.
Contributors:
    Linda DeMichiel - Java Persistence 2.1
    Linda DeMichiel - Java Persistence 2.0

/*******************************************************************************
 * Copyright (c) 2008 - 2013 Oracle Corporation. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
 * which accompanies this distribution.
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *     Linda DeMichiel - Java Persistence 2.1
 *     Linda DeMichiel - Java Persistence 2.0
 *
 ******************************************************************************/ 
package javax.persistence;


Utility interface between the application and the persistence
provider(s). 

 The PersistenceUtil interface instance obtained from the Persistence class is used to determine the load state of an entity or entity attribute regardless of which persistence provider in the environment created the entity. 
Since:Java Persistence 2.0
/**
 * Utility interface between the application and the persistence
 * provider(s). 
 * 
 * <p> The <code>PersistenceUtil</code> interface instance obtained from the 
 * {@link Persistence} class is used to determine the load state of an 
 * entity or entity attribute regardless of which persistence 
 * provider in the environment created the entity.
 *
 * @since Java Persistence 2.0
 */
public interface PersistenceUtil {

    
Determine the load state of a given persistent attribute.

Params:
  • entity –  entity containing the attribute
  • attributeName – name of attribute whose load state is
       to be determined
Returns:false if entity's state has not been loaded or
 if the attribute state has not been loaded, else true
/**
     * Determine the load state of a given persistent attribute.
     * @param entity  entity containing the attribute
     * @param attributeName name of attribute whose load state is
     *        to be determined
     * @return false if entity's state has not been loaded or
     *  if the attribute state has not been loaded, else true
     */
    public boolean isLoaded(Object entity, String attributeName);

    
Determine the load state of an entity.
This method can be used to determine the load state 
of an entity passed as a reference.  An entity is
considered loaded if all attributes for which 
FetchType.EAGER has been specified have been loaded.

 The isLoaded(Object, String) method should be used to 
determine the load state of an attribute.
Not doing so might lead to unintended loading of state.

Params:
  • entity – whose load state is to be determined
Returns:false if the entity has not been loaded, else true
/**
     * Determine the load state of an entity.
     * This method can be used to determine the load state 
     * of an entity passed as a reference.  An entity is
     * considered loaded if all attributes for which 
     * <code>FetchType.EAGER</code> has been specified have been loaded.
     * <p> The <code>isLoaded(Object, String)</code> method should be used to 
     * determine the load state of an attribute.
     * Not doing so might lead to unintended loading of state.
     * @param entity whose load state is to be determined
     * @return false if the entity has not been loaded, else true
     */
    public boolean isLoaded(Object entity);
}