HSQLDB example source code file (Trigger.java)

This example HSQLDB source code file (Trigger.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - HSQLDB tags/keywords

delete_after, delete_after, delete_before, insert_after, insert_after, insert_after_row, insert_before, insert_before, object, string, trigger, update_after, update_after, update_before

The HSQLDB Trigger.java source code

/* Copyright (c) 2001-2008, The HSQL Development Group
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the HSQL Development Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */


package org.hsqldb;

// fredt@users 20030727 - signature altered to support update triggers
/*

Contents of row1[] and row2[] in each type of trigger.

BEFORE INSERT
 - row1[] contains single String object = "Statement-level".

AFTER INSERT
 - row1[] contains single String object = "Statement-level".

BEFORE UPDATE
 - row1[] contains single String object = "Statement-level".

AFTER UPDATE
 - row1[] contains single String object = "Statement-level".

BEFORE DELETE
 - row1[] contains single String object = "Statement-level".

AFTER DELETE
 - row1[] contains single String object = "Statement-level".

BEFORE INSERT FOR EACH ROW
 - row2[] contains data about to be inserted and this can
be modified within the trigger such that modified data gets written to the
database.

AFTER INSERT FOR EACH ROW
 - row2[] contains data just inserted into the table.

BEFORE UPDATE FOR EACH ROW
 - row1[] contains currently stored data and not the data that is about to be
updated.

 - row2[] contains the data that is about to be updated.

AFTER UPDATE FOR EACH ROW
 - row1[] contains old stored data.
 - row2[] contains the new data.

BEFORE DELETE FOR EACH ROW
 - row1[] contains row data about to be deleted.

AFTER DELETE FOR EACH ROW
 - row1[] contains row data that has been deleted.

List compiled by Andrew Knight (quozzbat@users)
*/

/**
 * The interface an HSQLDB TRIGGER must implement. The user-supplied class that
 * implements this must have a default constructor.
 *
 * @author Peter Hudson
 * @version 1.7.2
 * @since 1.7.0
 */
public interface Trigger {

    // indexes into the triggers list
    int INSERT_AFTER      = 0;
    int DELETE_AFTER      = 1;
    int UPDATE_AFTER      = 2;
    int INSERT_BEFORE     = INSERT_AFTER + TriggerDef.NUM_TRIGGER_OPS;
    int DELETE_BEFORE     = DELETE_AFTER + TriggerDef.NUM_TRIGGER_OPS;
    int UPDATE_BEFORE     = UPDATE_AFTER + TriggerDef.NUM_TRIGGER_OPS;
    int INSERT_AFTER_ROW  = INSERT_AFTER + 2 * TriggerDef.NUM_TRIGGER_OPS;
    int DELETE_AFTER_ROW  = DELETE_AFTER + 2 * TriggerDef.NUM_TRIGGER_OPS;
    int UPDATE_AFTER_ROW  = UPDATE_AFTER + 2 * TriggerDef.NUM_TRIGGER_OPS;
    int INSERT_BEFORE_ROW = INSERT_BEFORE + 2 * TriggerDef.NUM_TRIGGER_OPS;
    int DELETE_BEFORE_ROW = DELETE_BEFORE + 2 * TriggerDef.NUM_TRIGGER_OPS;
    int UPDATE_BEFORE_ROW = UPDATE_BEFORE + 2 * TriggerDef.NUM_TRIGGER_OPS;

    /**
     * The method invoked upon each triggered action. <p>
     *
     * When UPDATE triggers are fired, oldRow contains the
     * existing values of the table row and newRow contains the
     * new values.<p>
     *
     * For INSERT triggers, oldRow is null and newRow contains the
     * table row to be inserted.
     *
     * For DELETE triggers, newRow is null and oldRow contains the
     * table row to be deleted.
     *
     * type contains the integer index id for trigger type, e.g.
     * TriggerDef.INSERT_AFTER (fredt@users)
     *
     * @param trigName the name of the trigger
     * @param tabName the name of the table upon which the
     *      triggered action is occuring
     * @param oldRow the old row
     * @param newRow the new row
     */
    void fire(int type, String trigName, String tabName, Object[] oldRow,
              Object[] newRow);
}