EDIT

/**

* Copyright (C) 2007 EDIT

* European Distributed Institute of Taxonomy

* http://www.e-taxonomy.eu

*

* The contents of this file are subject to the Mozilla Public License Version 1.1

* See LICENSE.TXT at the top of this package for the full license terms.

*/

package eu.etaxonomy.cdm.persistence.dao.hibernate.common;

import java.util.ArrayList;

import java.util.Collection;

import java.util.Collections;

import java.util.Comparator;

import java.util.HashMap;

import java.util.HashSet;

import java.util.Iterator;

import java.util.List;

import java.util.Map;

import java.util.Set;

import org.apache.log4j.Logger;

import org.hibernate.Criteria;

import org.hibernate.HibernateException;

import org.hibernate.Session;

import org.hibernate.SessionFactory;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.transaction.PlatformTransactionManager;

import eu.etaxonomy.cdm.persistence.query.OrderHint;

public abstract class DaoBase {

    final static Logger logger = Logger.getLogger(DaoBase.class);

    @Autowired

    private SessionFactory factory;

    @Autowired

    private PlatformTransactionManager transactionManager;

    public void setSessionFactory(SessionFactory sessionFactory) {

        this.factory = sessionFactory;

    }

    public SessionFactory getSessionFactory() {

        return factory;

    }

    protected Session getSession(){

        Session session ;

        try {

            session = factory.getCurrentSession();

        } catch (HibernateException e) {

            logger.error("Opening new session in turn of a HibernateException", e);

            session = factory.openSession();

        }

        return session;

    }

    public void flush(){

        getSession().flush();

    }

    private class OrderHintComparator implements Comparator<OrderHint> {

        @Override

        public int compare(OrderHint o1, OrderHint o2) {

            return o1.getPropertyName().compareTo(o2.getPropertyName());

        }

    }

    protected void addOrder(Criteria criteria, List<OrderHint> orderHints) {

        if(orderHints != null){

            Collections.sort(orderHints, new OrderHintComparator());

            Map<String,Criteria> criteriaMap = new HashMap<>();

            for(OrderHint orderHint : orderHints){

                orderHint.add(criteria, criteriaMap);

            }

        }

    }

    /**

     * Null save method which compiles a order by clause from the given list of OrderHints

     *

     * @param orderHints can be NULL

     * @return a StringBuffer holding the hql orderby clause

     */

    protected StringBuffer orderByClause(List<OrderHint> orderHints, String aliasName) {

        StringBuffer orderString = new StringBuffer();

        StringBuffer aliasPrefix = new StringBuffer();

        aliasPrefix.append(" ");

        if(aliasName != null && !aliasName.isEmpty()){

            aliasPrefix.append(aliasName).append(".");

        }

        if(orderHints != null && !orderHints.isEmpty()) {

            orderString.append(" order by");

            for(OrderHint orderHint : orderHints) {

                orderString.append(aliasPrefix).append(orderHint.toHql());

            }

        }

        return orderString;

    }

    /**

     * Splits a set of e.g. query parameters into a list of sets with size <code>splitSize</code>.

     * Only the last set may be smaller if the collection's size is not an exact multiple of split size.

     * @param collection the collection to split

     * @param splitSize the split size

     * @return a list of collections

     */

    protected <T extends Object> List<Collection<T>> splitCollection(Set<T> collection, int splitSize) {

        if (splitSize < 1){

            throw new IllegalArgumentException("Split size must not be positive integer");

        }

        List<Collection<T>> result = new ArrayList<>();

        Iterator<T> it = collection.iterator();

        int i = 0;

        Set<T> nextCollection = new HashSet<>();

        while (it.hasNext()){

            nextCollection.add(it.next());

            i++;

            if (i == splitSize){

                result.add(nextCollection);

                nextCollection = new HashSet<>();

                i = 0;

            }

        }

        if (!nextCollection.isEmpty()){

            result.add(nextCollection);

        }

        return result;

    }

}