All Downloads are FREE. Search and download functionalities are using the official Maven repository.

org.hibernate.usertype.UserType Maven / Gradle / Ivy

There is a newer version: 7.0.0.Alpha1
Show newest version
/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2011, Red Hat Inc. or third-party contributors as
 * indicated by the @author tags or express copyright attribution
 * statements applied by the authors.  All third-party contributions are
 * distributed under license by Red Hat Inc.
 *
 * This copyrighted material is made available to anyone wishing to use, modify,
 * copy, or redistribute it subject to the terms and conditions of the GNU
 * Lesser General Public License, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this distribution; if not, write to:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 * Boston, MA  02110-1301  USA
 */
package org.hibernate.usertype;

import java.io.Serializable;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import org.hibernate.HibernateException;
import org.hibernate.engine.spi.SessionImplementor;

/**
 * This interface should be implemented by user-defined "types".
 * A "type" class is not the actual property type - it
 * is a class that knows how to serialize instances of another
 * class to and from JDBC.
*
* This interface *
    *
  • abstracts user code from future changes to the Type * interface,
  • *
  • simplifies the implementation of custom types and
  • *
  • hides certain "internal" interfaces from user code.
  • *
*
* Implementors must be immutable and must declare a public * default constructor.
*
* The actual class mapped by a UserType may be just * about anything.
*
* CompositeUserType provides an extended version of * this interface that is useful for more complex cases.
*
* Alternatively, custom types could implement Type * directly or extend one of the abstract classes in * org.hibernate.type. This approach risks future * incompatible changes to classes or interfaces in that * package. * * @see CompositeUserType for more complex cases * @see org.hibernate.type.Type * @author Gavin King */ public interface UserType { /** * Return the SQL type codes for the columns mapped by this type. The * codes are defined on java.sql.Types. * @see java.sql.Types * @return int[] the typecodes */ public int[] sqlTypes(); /** * The class returned by nullSafeGet(). * * @return Class */ public Class returnedClass(); /** * Compare two instances of the class mapped by this type for persistence "equality". * Equality of the persistent state. * * @param x * @param y * @return boolean */ public boolean equals(Object x, Object y) throws HibernateException; /** * Get a hashcode for the instance, consistent with persistence "equality" */ public int hashCode(Object x) throws HibernateException; /** * Retrieve an instance of the mapped class from a JDBC resultset. Implementors * should handle possibility of null values. * * * @param rs a JDBC result set * @param names the column names * @param session *@param owner the containing entity @return Object * @throws HibernateException * @throws SQLException */ public Object nullSafeGet(ResultSet rs, String[] names, SessionImplementor session, Object owner) throws HibernateException, SQLException; /** * Write an instance of the mapped class to a prepared statement. Implementors * should handle possibility of null values. A multi-column type should be written * to parameters starting from index. * * * @param st a JDBC prepared statement * @param value the object to write * @param index statement parameter index * @param session * @throws HibernateException * @throws SQLException */ public void nullSafeSet(PreparedStatement st, Object value, int index, SessionImplementor session) throws HibernateException, SQLException; /** * Return a deep copy of the persistent state, stopping at entities and at * collections. It is not necessary to copy immutable objects, or null * values, in which case it is safe to simply return the argument. * * @param value the object to be cloned, which may be null * @return Object a copy */ public Object deepCopy(Object value) throws HibernateException; /** * Are objects of this type mutable? * * @return boolean */ public boolean isMutable(); /** * Transform the object into its cacheable representation. At the very least this * method should perform a deep copy if the type is mutable. That may not be enough * for some implementations, however; for example, associations must be cached as * identifier values. (optional operation) * * @param value the object to be cached * @return a cachable representation of the object * @throws HibernateException */ public Serializable disassemble(Object value) throws HibernateException; /** * Reconstruct an object from the cacheable representation. At the very least this * method should perform a deep copy if the type is mutable. (optional operation) * * @param cached the object to be cached * @param owner the owner of the cached object * @return a reconstructed object from the cachable representation * @throws HibernateException */ public Object assemble(Serializable cached, Object owner) throws HibernateException; /** * During merge, replace the existing (target) value in the entity we are merging to * with a new (original) value from the detached entity we are merging. For immutable * objects, or null values, it is safe to simply return the first parameter. For * mutable objects, it is safe to return a copy of the first parameter. For objects * with component values, it might make sense to recursively replace component values. * * @param original the value from the detached entity being merged * @param target the value in the managed entity * @return the value to be merged */ public Object replace(Object original, Object target, Object owner) throws HibernateException; }




© 2015 - 2024 Weber Informatics LLC | Privacy Policy