org.hibernate.classic.Lifecycle.java Source code

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Here is the source code for org.hibernate.classic.Lifecycle.java

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/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
 * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
 */
package org.hibernate.classic;

import java.io.Serializable;

import org.hibernate.CallbackException;
import org.hibernate.Session;

/**
 * Provides callbacks from the <tt>Session</tt> to the persistent object.
 * Persistent classes <b>may</b> implement this interface but they are not
 * required to.<br>
 * <br>
 * <b>onSave:</b> called just before the object is saved<br>
 * <b>onUpdate:</b> called just before an object is updated,
 * ie. when <tt>Session.update()</tt> is called<br>
 * <b>onDelete:</b> called just before an object is deleted<br>
 * <b>onLoad:</b> called just after an object is loaded<br>
 * <br>
 * <tt>onLoad()</tt> may be used to initialize transient properties of the
 * object from its persistent state. It may <b>not</b> be used to load
 * dependent objects since the <tt>Session</tt> interface may not be
 * invoked from inside this method.<br>
 * <br>
 * A further intended usage of <tt>onLoad()</tt>, <tt>onSave()</tt> and
 * <tt>onUpdate()</tt> is to store a reference to the <tt>Session</tt>
 * for later use.<br>
 * <br>
 * If <tt>onSave()</tt>, <tt>onUpdate()</tt> or <tt>onDelete()</tt> return
 * <tt>VETO</tt>, the operation is silently vetoed. If a
 * <tt>CallbackException</tt> is thrown, the operation is vetoed and the
 * exception is passed back to the application.<br>
 * <br>
 * Note that <tt>onSave()</tt> is called after an identifier is assigned
 * to the object, except when identity column key generation is used.
 *
 * @see CallbackException
 * @author Gavin King
 */
public interface Lifecycle {

    /**
     * Return value to veto the action (true)
     */
    public static final boolean VETO = true;

    /**
     * Return value to accept the action (false)
     */
    public static final boolean NO_VETO = false;

    /**
     * Called when an entity is saved.
     * @param s the session
     * @return true to veto save
     * @throws CallbackException Indicates a problem happened during callback
     */
    public boolean onSave(Session s) throws CallbackException;

    /**
     * Called when an entity is passed to <tt>Session.update()</tt>.
     * This method is <em>not</em> called every time the object's
     * state is persisted during a flush.
     * @param s the session
     * @return true to veto update
     * @throws CallbackException Indicates a problem happened during callback
     */
    public boolean onUpdate(Session s) throws CallbackException;

    /**
     * Called when an entity is deleted.
     * @param s the session
     * @return true to veto delete
     * @throws CallbackException Indicates a problem happened during callback
     */
    public boolean onDelete(Session s) throws CallbackException;

    /**
     * Called after an entity is loaded. <em>It is illegal to
     * access the <tt>Session</tt> from inside this method.</em>
     * However, the object may keep a reference to the session
     * for later use.
     *
     * @param s the session
     * @param id the identifier
     */
    public void onLoad(Session s, Serializable id);
}