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Hibernate example source code file (UniqueKey.java)

This example Hibernate source code file (UniqueKey.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

column, column, constraint, dialect, iterator, iterator, mapping, string, string, stringbuffer, stringbuffer, uniquekey, util

The Hibernate UniqueKey.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.mapping;
import java.util.Iterator;
import org.hibernate.dialect.Dialect;
import org.hibernate.engine.spi.Mapping;
import org.hibernate.internal.util.StringHelper;

/**
 * A relational unique key constraint
 *
 * @author Gavin King
 */
public class UniqueKey extends Constraint {

	public String sqlConstraintString(Dialect dialect) {
		StringBuffer buf = new StringBuffer( "unique (" );
		boolean hadNullableColumn = false;
		Iterator iter = getColumnIterator();
		while ( iter.hasNext() ) {
			Column column = (Column) iter.next();
			if ( !hadNullableColumn && column.isNullable() ) {
				hadNullableColumn = true;
			}
			buf.append( column.getQuotedName( dialect ) );
			if ( iter.hasNext() ) {
				buf.append( ", " );
			}
		}
		//do not add unique constraint on DB not supporting unique and nullable columns
		return !hadNullableColumn || dialect.supportsNotNullUnique() ?
				buf.append( ')' ).toString() :
				null;
	}

	public String sqlConstraintString(
			Dialect dialect,
			String constraintName,
			String defaultCatalog,
			String defaultSchema) {
		StringBuffer buf = new StringBuffer(
				dialect.getAddPrimaryKeyConstraintString( constraintName )
		).append( '(' );
		Iterator iter = getColumnIterator();
		boolean nullable = false;
		while ( iter.hasNext() ) {
			Column column = (Column) iter.next();
			if ( !nullable && column.isNullable() ) nullable = true;
			buf.append( column.getQuotedName( dialect ) );
			if ( iter.hasNext() ) buf.append( ", " );
		}
		return !nullable || dialect.supportsNotNullUnique() ?
				StringHelper.replace( buf.append( ')' ).toString(), "primary key", "unique" ) :
				//TODO: improve this hack!
				null;
	}

	public String sqlCreateString(Dialect dialect, Mapping p, String defaultCatalog, String defaultSchema) {
		if ( dialect.supportsUniqueConstraintInCreateAlterTable() ) {
			return super.sqlCreateString( dialect, p, defaultCatalog, defaultSchema );
		}
		else {
			return Index.buildSqlCreateIndexString( dialect, getName(), getTable(), getColumnIterator(), true,
					defaultCatalog, defaultSchema );
		}
	}

	public String sqlDropString(Dialect dialect, String defaultCatalog, String defaultSchema) {
		if ( dialect.supportsUniqueConstraintInCreateAlterTable() ) {
			return super.sqlDropString( dialect, defaultCatalog, defaultSchema );
		}
		else {
			return Index.buildSqlDropIndexString( dialect, getTable(), getName(), defaultCatalog, defaultSchema );
		}
	}

	public boolean isGenerated(Dialect dialect) {
		if ( dialect.supportsNotNullUnique() ) return true;
		Iterator iter = getColumnIterator();
		while ( iter.hasNext() ) {
			if ( ( (Column) iter.next() ).isNullable() ) {
				return false;
			}
		}
		return true;
	}

}

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