constraint.java

开源的axion的数据库代码

/*
 * $Id: Constraint.java,v 1.13 2003/02/12 16:19:54 cburdick Exp $
 * =======================================================================
 * Copyright (c) 2002 Axion Development Team.  All rights reserved.
 *  
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions 
 * are met:
 * 
 * 1. Redistributions of source code must retain the above 
 *    copyright notice, this list of conditions and the following 
 *    disclaimer. 
 *   
 * 2. 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. 
 *   
 * 3. The names "Tigris", "Axion", nor the names of its contributors may 
 *    not be used to endorse or promote products derived from this 
 *    software without specific prior written permission. 
 *  
 * 4. Products derived from this software may not be called "Axion", nor 
 *    may "Tigris" or "Axion" appear in their names 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 THE COPYRIGHT 
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * =======================================================================
 */

package org.axiondb;

import org.axiondb.event.RowEvent;

/**
 * A database constraint, such as UNIQUE or NOT NULL.
 * 
 * @version $Revision: 1.13 $ $Date: 2003/02/12 16:19:54 $
 * @author Rodney Waldhoff
 * @author James Strachan
 */
public interface Constraint {
    /**
     * Resolve any unresolved {@link org.axiondb.Selectable
     * identifiers} I may have.
     */
    void resolve(Database db, TableIdentifier table) throws AxionException;

    /**
     * Evaluate the given <i>event</i> under me.  Returns <code>false</code>
     * if the constraint I represent has been violated.
     */
    boolean evaluate(RowEvent event) throws AxionException;
    
    /**
     * Return whether or not I am deferred.  Deferred constraints are
     * not evaluated until the transaction is committed.
     */
    boolean isDeferred();
    
    /**
     * Set whether or not I am deferred.  Deferred constraints are not
     * evaluated until the transaction is committed.  Throws an
     * exception if I am not {@link #isDeferrable deferrable} and
     * <i>deferred</i> is <code>true</code>.
     */
    void setDeferred(boolean deferred) throws AxionException;

    /**
     * Return whether or not I am deferrable.
     */
    boolean isDeferrable();

    /**
     * Set whether or not I am deferrable.
     */
    void setDeferrable(boolean deferrable);
    
    /**
     * Get my name.
     */
    String getName();

    /**
     * Set my name.
     */
    void setName(String name);

    /**
     * Get a human-readable descrption of the type of constraint I represent.
     */
    String getType();
}