Hibernate example source code file (ComponentJoin.java)

This example Hibernate source code file (ComponentJoin.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

componentfromelementtype, componentjoin, componenttype, fromelement, override, override, propertymapping, propertymapping, queryexception, string, string, stringbuffer, type, type

The Hibernate ComponentJoin.java source code

/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2009 by Red Hat Inc and/or its affiliates or by
 * third-party contributors as indicated by either @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.hql.internal.ast.tree;

import org.hibernate.QueryException;
import org.hibernate.hql.internal.NameGenerator;
import org.hibernate.internal.util.StringHelper;
import org.hibernate.persister.collection.QueryableCollection;
import org.hibernate.persister.entity.PropertyMapping;
import org.hibernate.type.ComponentType;
import org.hibernate.type.Type;

/**
 * Models an explicit join terminating at a component value (e.g. <tt>... from Person p join p.name as n ...)
 *
 * @author Steve Ebersole
 */
public class ComponentJoin extends FromElement {
	private final String componentPath;
	private final ComponentType componentType;

	private final String componentProperty;
	private final String columns;

	public ComponentJoin(
			FromClause fromClause,
			FromElement origin,
			String alias,
			String componentPath,
			ComponentType componentType) {
		super( fromClause, origin, alias );
		this.componentPath = componentPath;
		this.componentType = componentType;
		this.componentProperty = StringHelper.unqualify( componentPath );
		fromClause.addJoinByPathMap( componentPath, this );
		initializeComponentJoin( new ComponentFromElementType( this ) );

		final String[] cols = origin.getPropertyMapping( "" ).toColumns( getTableAlias(), componentProperty );
		StringBuffer buf = new StringBuffer();
		for ( int j = 0; j < cols.length; j++ ) {
			final String column = cols[j];
			if ( j > 0 ) {
				buf.append( ", " );
			}
			buf.append( column );
		}
		this.columns = buf.toString();
	}

	public String getComponentPath() {
		return componentPath;
	}

	public String getComponentProperty() {
		return componentProperty;
	}

	public ComponentType getComponentType() {
		return componentType;
	}


	@Override
    public Type getDataType() {
		return getComponentType();
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
    public String getIdentityColumn() {
		// used to "resolve" the IdentNode when our alias is encountered *by itself* in the query; so
		//		here we use the component
		// NOTE : ^^ is true *except for* when encountered by itself in the SELECT clause.  That gets
		// 		routed through org.hibernate.hql.internal.ast.tree.ComponentJoin.ComponentFromElementType.renderScalarIdentifierSelect()
		//		which we also override to account for
		return columns;
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
    public String getDisplayText() {
		return "ComponentJoin{path=" + getComponentPath() + ", type=" + componentType.getReturnedClass() + "}";
	}

	public class ComponentFromElementType extends FromElementType {
		private final PropertyMapping propertyMapping = new ComponentPropertyMapping();

		public ComponentFromElementType(FromElement fromElement) {
			super( fromElement );
		}

		@Override
        public Type getDataType() {
			return getComponentType();
		}

		/**
		 * {@inheritDoc}
		 */
		@Override
        public QueryableCollection getQueryableCollection() {
			return null;
		}

		/**
		 * {@inheritDoc}
		 */
		@Override
        public PropertyMapping getPropertyMapping(String propertyName) {
			return propertyMapping;
		}

		/**
		 * {@inheritDoc}
		 */
		@Override
        public Type getPropertyType(String propertyName, String propertyPath) {
			int index = getComponentType().getPropertyIndex( propertyName );
			return getComponentType().getSubtypes()[index];
		}

		@Override
        public String renderScalarIdentifierSelect(int i) {
			String[] cols = getBasePropertyMapping().toColumns( getTableAlias(), getComponentProperty() );
			StringBuffer buf = new StringBuffer();
			// For property references generate <tablealias>. as 
			for ( int j = 0; j < cols.length; j++ ) {
				final String column = cols[j];
				if ( j > 0 ) {
					buf.append( ", " );
				}
				buf.append( column ).append( " as " ).append( NameGenerator.scalarName( i, j ) );
			}
			return buf.toString();
		}
	}

	protected PropertyMapping getBasePropertyMapping() {
		return getOrigin().getPropertyMapping( "" );
	}

	private final class ComponentPropertyMapping implements PropertyMapping {
		public Type getType() {
			return getComponentType();
		}

		public Type toType(String propertyName) throws QueryException {
			return getBasePropertyMapping().toType( getPropertyPath( propertyName ) );
		}

		protected String getPropertyPath(String propertyName) {
			return getComponentPath() + '.' + propertyName;
		}

		public String[] toColumns(String alias, String propertyName) throws QueryException {
			return getBasePropertyMapping().toColumns( alias, getPropertyPath( propertyName ) );
		}

		public String[] toColumns(String propertyName) throws QueryException, UnsupportedOperationException {
			return getBasePropertyMapping().toColumns( getPropertyPath( propertyName ) );
		}
	}
}