Hibernate example source code file (ResultColumnReferenceStrategy.java)

This example Hibernate source code file (ResultColumnReferenceStrategy.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

alias, hashmap, io, map, object, object, objectstreamexception, ordinal, resultcolumnreferencestrategy, resultcolumnreferencestrategy, serializable, source, source, string, string, util

The Hibernate ResultColumnReferenceStrategy.java source code

/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2010, 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.dialect;
import java.io.ObjectStreamException;
import java.io.Serializable;
import java.util.HashMap;
import java.util.Map;

/**
 * Defines how we need to reference columns in the group-by, having, and order-by
 * clauses.
 *
 * @author Steve Ebersole
 */
public class ResultColumnReferenceStrategy implements Serializable {

	private static final Map INSTANCES = new HashMap();

	/**
	 * This strategy says to reference the result columns by the qualified column name
	 * found in the result source.  This strategy is not strictly allowed by ANSI SQL
	 * but is Hibernate's legacy behavior and is also the fastest of the strategies; thus
	 * it should be used if supported by the underlying database.
	 */
	public static final ResultColumnReferenceStrategy SOURCE = new ResultColumnReferenceStrategy( "source");

	/**
	 * For databases which do not support {@link #SOURCE}, ANSI SQL defines two allowable
	 * approaches.  One is to reference the result column by the alias it is given in the
	 * result source (if it is given an alias).  This strategy says to use this approach.
	 * <p/>
	 * The other QNSI SQL compliant approach is {@link #ORDINAL}.
	 */
	public static final ResultColumnReferenceStrategy ALIAS = new ResultColumnReferenceStrategy( "alias" );

	/**
	 * For databases which do not support {@link #SOURCE}, ANSI SQL defines two allowable
	 * approaches.  One is to reference the result column by the ordinal position at which
	 * it appears in the result source.  This strategy says to use this approach.
	 * <p/>
	 * The other QNSI SQL compliant approach is {@link #ALIAS}.
	 */
	public static final ResultColumnReferenceStrategy ORDINAL = new ResultColumnReferenceStrategy( "ordinal" );

	static {
		ResultColumnReferenceStrategy.INSTANCES.put( ResultColumnReferenceStrategy.SOURCE.name, ResultColumnReferenceStrategy.SOURCE );
		ResultColumnReferenceStrategy.INSTANCES.put( ResultColumnReferenceStrategy.ALIAS.name, ResultColumnReferenceStrategy.ALIAS );
		ResultColumnReferenceStrategy.INSTANCES.put( ResultColumnReferenceStrategy.ORDINAL.name, ResultColumnReferenceStrategy.ORDINAL );
	}

	private final String name;

	public ResultColumnReferenceStrategy(String name) {
		this.name = name;
	}

	public String toString() {
		return name;
	}

	private Object readResolve() throws ObjectStreamException {
		return parse( name );
	}

	public static ResultColumnReferenceStrategy parse(String name) {
		return ( ResultColumnReferenceStrategy ) ResultColumnReferenceStrategy.INSTANCES.get( name );
	}
}