Hibernate example source code file (UnsavedValueFactory.java)

This example Hibernate source code file (UnsavedValueFactory.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 - Hibernate tags/keywords

constructor, could, exception, getter, identifiervalue, identifiervalue, io, mappingexception, mappingexception, object, object, primitivetype, reflection, serializable, serializable, string

The Hibernate UnsavedValueFactory.java source code

/*
 * 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.engine.internal;

import java.io.Serializable;
import java.lang.reflect.Constructor;

import org.hibernate.InstantiationException;
import org.hibernate.MappingException;
import org.hibernate.engine.spi.IdentifierValue;
import org.hibernate.engine.spi.VersionValue;
import org.hibernate.property.Getter;
import org.hibernate.type.IdentifierType;
import org.hibernate.type.PrimitiveType;
import org.hibernate.type.Type;
import org.hibernate.type.VersionType;

/**
 * @author Gavin King
 */
public class UnsavedValueFactory {
	
	private static Object instantiate(Constructor constructor) {
		try {
			return constructor.newInstance( (Object[]) null );
		}
		catch (Exception e) {
			throw new InstantiationException( "could not instantiate test object", constructor.getDeclaringClass(), e );
		}
	}
	
	/**
	 * Return an IdentifierValue for the specified unsaved-value. If none is specified, 
	 * guess the unsaved value by instantiating a test instance of the class and
	 * reading it's id property, or if that is not possible, using the java default
	 * value for the type 
	 */
	public static IdentifierValue getUnsavedIdentifierValue(
			String unsavedValue, 
			Getter identifierGetter,
			Type identifierType,
			Constructor constructor) {
		
		if ( unsavedValue == null ) {
			if ( identifierGetter!=null && constructor!=null ) {
				// use the id value of a newly instantiated instance as the unsaved-value
				Serializable defaultValue = (Serializable) identifierGetter.get( instantiate(constructor) );
				return new IdentifierValue( defaultValue );
			}
			else if ( identifierGetter != null && (identifierType instanceof PrimitiveType) ) {
				Serializable defaultValue = ( ( PrimitiveType ) identifierType ).getDefaultValue();
				return new IdentifierValue( defaultValue );
			}
			else {
				return IdentifierValue.NULL;
			}
		}
		else if ( "null".equals( unsavedValue ) ) {
			return IdentifierValue.NULL;
		}
		else if ( "undefined".equals( unsavedValue ) ) {
			return IdentifierValue.UNDEFINED;
		}
		else if ( "none".equals( unsavedValue ) ) {
			return IdentifierValue.NONE;
		}
		else if ( "any".equals( unsavedValue ) ) {
			return IdentifierValue.ANY;
		}
		else {
			try {
				return new IdentifierValue( ( Serializable ) ( ( IdentifierType ) identifierType ).stringToObject( unsavedValue ) );
			}
			catch ( ClassCastException cce ) {
				throw new MappingException( "Bad identifier type: " + identifierType.getName() );
			}
			catch ( Exception e ) {
				throw new MappingException( "Could not parse identifier unsaved-value: " + unsavedValue );
			}
		}
	}

	public static VersionValue getUnsavedVersionValue(
			String versionUnsavedValue, 
			Getter versionGetter,
			VersionType versionType,
			Constructor constructor) {
		
		if ( versionUnsavedValue == null ) {
			if ( constructor!=null ) {
				Object defaultValue = versionGetter.get( instantiate(constructor) );
				// if the version of a newly instantiated object is not the same
				// as the version seed value, use that as the unsaved-value
				return versionType.isEqual( versionType.seed( null ), defaultValue ) ?
						VersionValue.UNDEFINED :
						new VersionValue( defaultValue );
			}
			else {
				return VersionValue.UNDEFINED;
			}
		}
		else if ( "undefined".equals( versionUnsavedValue ) ) {
			return VersionValue.UNDEFINED;
		}
		else if ( "null".equals( versionUnsavedValue ) ) {
			return VersionValue.NULL;
		}
		else if ( "negative".equals( versionUnsavedValue ) ) {
			return VersionValue.NEGATIVE;
		}
		else {
			// this should not happen since the DTD prevents it
			throw new MappingException( "Could not parse version unsaved-value: " + versionUnsavedValue );
		}
		
	}

}