BaseCriteriaBuildAndSort.java

package net.databinder.models.hib;

/*---
 Copyright 2008 The Scripps Research Institute
 http://www.scripps.edu
 
* Databinder: a simple bridge from Wicket to Hibernate
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
* 
* This library 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 library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 ---*/

import java.io.Serializable;
import java.util.HashSet;
import java.util.Set;

import org.hibernate.Criteria;
import org.hibernate.criterion.CriteriaSpecification;
import org.hibernate.criterion.Order;

/**
 * Abstract base class for building OrderedCriteriaBuilders. It handles the sorting.
 * Subclasses should call super.buildUnordered() when overriding.
 * 
 * Avoids problems with duplicate Aliases by having all the Criteria building code in one location.
 */
public abstract class BaseCriteriaBuildAndSort implements OrderingCriteriaBuilder, Serializable {

	protected Set<String> aliases = new HashSet<String>();

	protected String defaultSortProperty = null;

	protected boolean sortAscending, sortCased;

	public BaseCriteriaBuildAndSort() {
		this(null, true, false);
	}

	public BaseCriteriaBuildAndSort(final String defaultSortProperty, final boolean sortAscending, final boolean sortCased) {
		this.defaultSortProperty = defaultSortProperty;
		this.sortAscending = sortAscending;
		this.sortCased = sortCased;
	}

	public void buildOrdered(final Criteria criteria) {
		buildUnordered(criteria);

		String property = defaultSortProperty;
		if (property != null) {
			property = processProperty(criteria, property);
			Order order = sortAscending ? Order.asc(property) : Order.desc(property);
			order = sortCased ? order : order.ignoreCase();
			criteria.addOrder(order);
		}
	}

	public void buildUnordered(final Criteria criteria) {
		aliases.clear();
	}

	protected String processProperty(final Criteria criteria, String property) {
		if (property.contains(".")) {
			// for 'dot' properties we need to add aliases
			// e.g. for the property 'orderbook.order.item.name' we need to add an aliases for 'order' and 'order.item'
			String path[] = property.split("\\.");
			for (int ii = 0; ii < path.length - 1; ii++) {
				StringBuffer sb = new StringBuffer();
				for (int jj = 0; jj <= ii; jj++) {
					if (sb.length() > 0) {
						sb.append(".");
					}
					sb.append(path[jj]);
				}
				if (!aliases.contains(path[ii])) {
					aliases.add(path[ii]);
					criteria.createAlias(sb.toString(), path[ii], CriteriaSpecification.LEFT_JOIN);
				}
			}
			// when we have a 'dot' property we want to sort by the sub tables field
			// e.g. for the property 'orderbook.order.item.name' we need to sort by 'item.name'
			if (path.length > 1) {
				property = String.format("%s.%s", path[path.length - 2], path[path.length - 1]);
			}
			else {
				property = path[path.length - 1];
			}
		}
		return property;
	}
}