import play.db.jpa.Model; //导入依赖的package包/类
/**
 * Lookups the id field, being a Long id for Model and an annotated field @Id
 * for JPABase and returns the field value.
 * 
 * @param jpaBase is a Play! Framework that supports JPA
 * @return the field value (a Long or a String for UUID)
 */
public static Object getIdValueFor(JPABase jpaBase) {
    if (jpaBase instanceof Model) {
        return ((Model ) jpaBase).id;
    }

    java.lang.reflect.Field field = getIdField(jpaBase.getClass());
    Object val = null;
    try {
        val = field.get(jpaBase);
    } catch (IllegalAccessException e) {
        Logger.error("Unable to read the field value of a field annotated with @Id " + field.getName() + " due to "
                        + e.getMessage(), e);
    }
    return val;
}
 

import play.db.jpa.Model; //导入依赖的package包/类
/**
 *
 * {@inheritDoc}
 */
@Override
public boolean isSatisfied(Object validatedObject, Object value,
        OValContext context, Validator validator) {
    requireMessageVariablesRecreation();
    if (value == null) {
        return true;
    }
    final String[] propertyNames = getPropertyNames(
            ((FieldContext) context).getField().getName());
    final GenericModel model = (GenericModel) validatedObject;
    final Model.Factory factory =  Model.Manager.factoryFor(model.getClass());
    final String keyProperty = StringUtils.capitalize(factory.keyName());
    final Object keyValue = factory.keyValue(model);
    //In case of an update make sure that we won't read the current record from database.
    final boolean isUpdate = (keyValue != null);
    final String entityName = model.getClass().getName();
    final StringBuffer jpql = new StringBuffer("SELECT COUNT(o) FROM ");
    jpql.append(entityName).append(" AS o where ");
    final Object[] values = new Object[isUpdate ? propertyNames.length + 1 :
            propertyNames.length];
    final Class clazz = validatedObject.getClass();
    for (int i = 0; i < propertyNames.length; i++) {
        Field field = getField(clazz, propertyNames[i]);
        field.setAccessible(true);
        try {
            values[i] = field.get(model);
        } catch (Exception ex) {
            throw new UnexpectedException(ex);
        }
        if (i > 0) {
            jpql.append(" And ");
        }
        jpql.append("o.").append(propertyNames[i]).append(" = ? ");
    }
    if (isUpdate) {
        values[propertyNames.length] = keyValue;
        jpql.append(" and ").append(keyProperty).append(" <>  ?");
    }
    return JPQL.instance.count(entityName, jpql.toString(), values) == 0L;
}