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A module of the Hibernate Core project
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/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2008, Red Hat Middleware LLC 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 Middleware LLC.
 *
 * 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.loader.custom;

import java.util.Map;

import org.hibernate.internal.util.StringHelper;
import org.hibernate.loader.CollectionAliases;
import org.hibernate.persister.collection.SQLLoadableCollection;

/**
 * CollectionAliases that uses columnnames instead of generated aliases.
 * Aliases can still be overwritten via 
 *
 * @author Max Rydahl Andersen
 *
 */
public class ColumnCollectionAliases implements CollectionAliases {
	private final String[] keyAliases;
	private final String[] indexAliases;
	private final String[] elementAliases;
	private final String identifierAlias;
	private Map userProvidedAliases;


	public ColumnCollectionAliases(Map userProvidedAliases, SQLLoadableCollection persister) {
		this.userProvidedAliases = userProvidedAliases;

		this.keyAliases = getUserProvidedAliases(
				"key",
				persister.getKeyColumnNames()
			);

		this.indexAliases = getUserProvidedAliases(
				"index",
				persister.getIndexColumnNames()
				);

		this.elementAliases = getUserProvidedAliases( "element",
				persister.getElementColumnNames()
				);

		this.identifierAlias = getUserProvidedAlias( "id",
				persister.getIdentifierColumnName()
				);

	}


	/**
	 * Returns the suffixed result-set column-aliases for columns making up the key for this collection (i.e., its FK to
	 * its owner).
	 *
	 * @return The key result-set column aliases.
	 */
	public String[] getSuffixedKeyAliases() {
		return keyAliases;
	}

	/**
	 * Returns the suffixed result-set column-aliases for the collumns making up the collection's index (map or list).
	 *
	 * @return The index result-set column aliases.
	 */
	public String[] getSuffixedIndexAliases() {
		return indexAliases;
	}

	/**
	 * Returns the suffixed result-set column-aliases for the columns making up the collection's elements.
	 *
	 * @return The element result-set column aliases.
	 */
	public String[] getSuffixedElementAliases() {
		return elementAliases;
	}

	/**
	 * Returns the suffixed result-set column-aliases for the column defining the collection's identifier (if any).
	 *
	 * @return The identifier result-set column aliases.
	 */
	public String getSuffixedIdentifierAlias() {
		return identifierAlias;
	}

	/**
	 * Returns the suffix used to unique the column aliases for this particular alias set.
	 *
	 * @return The uniqued column alias suffix.
	 */
	public String getSuffix() {
		return "";
	}

	@Override
    public String toString() {
		return super.toString() + " [ suffixedKeyAliases=[" + join( keyAliases ) +
		        "], suffixedIndexAliases=[" + join( indexAliases ) +
		        "], suffixedElementAliases=[" + join( elementAliases ) +
		        "], suffixedIdentifierAlias=[" + identifierAlias + "]]";
	}

	private String join(String[] aliases) {
		if ( aliases == null) return null;

		return StringHelper.join( ", ", aliases );
	}

	private String[] getUserProvidedAliases(String propertyPath, String[] defaultAliases) {
		String[] result = (String[]) userProvidedAliases.get(propertyPath);
		if (result==null) {
			return defaultAliases;
		}
		else {
			return result;
		}
	}

	private String getUserProvidedAlias(String propertyPath, String defaultAlias) {
		String[] columns = (String[]) userProvidedAliases.get(propertyPath);
		if (columns==null) {
			return defaultAlias;
		}
		else {
			return columns[0];
		}
	}

}