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.Optional;

import java.util.Set;

import org.apache.log4j.Logger;

import org.apache.lucene.search.Sort;

import org.apache.lucene.search.SortField;

import org.hibernate.Criteria;

import org.hibernate.HibernateException;

import org.hibernate.Session;

import org.hibernate.SessionFactory;

import org.hibernate.criterion.Criterion;

import org.hibernate.search.FullTextQuery;

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

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

public abstract class DaoBase {

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

    public final static boolean NO_UNPUBLISHED = false;  //constant for unpublished

    public final static boolean INCLUDE_UNPUBLISHED = true;  //constant for unpublished

    @Autowired

    private SessionFactory factory;

    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) {

            if (o1.equals(o2)){

                return 0;

            }

            int result = o1.getPropertyName().compareTo(o2.getPropertyName());

            if (result == 0){

                result = o1.toString().compareTo(o2.toString());

            }

            return result;

        }

    }

    /**

     * 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;

    }

    // -------------- hql, query and criteria helper methods -------------- //

    protected void addFieldPredicate(StringBuilder hql, String field, Optional<String> value) {

        if(value != null){

            hql.append("and " + field);

            if(value.isPresent()){

                if(value.get().contains("*")){

                    hql.append(" like '" + value.get().replace('*', '%') + "' ");

                } else {

                    hql.append(" = '" + value.get() + "' ");

                }

            } else {

                hql.append(" is null ");

            }

        }

    }

    /**

     * @param limit

     * @param start

     * @param criteria

     */

    protected void addLimitAndStart(Integer limit, Integer start, Criteria criteria) {

        if(limit != null) {

            if(start != null) {

                criteria.setFirstResult(start);

            } else {

                criteria.setFirstResult(0);

            }

            criteria.setMaxResults(limit);

        }

    }

    protected void addCriteria(Criteria criteria, List<Criterion> criterion) {

        if(criterion != null) {

            for(Criterion c : criterion) {

                criteria.add(c);

            }

        }

    }

    /**

     * Null save method which compiles an 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(" ");

        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;

    }

    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);

            }

        }

    }

    protected void addOrder(FullTextQuery fullTextQuery, List<OrderHint> orderHints) {

        //FIXME preliminary hardcoded type:

        SortField.Type type = SortField.Type.STRING;

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

            org.apache.lucene.search.Sort sort = new Sort();

            SortField[] sortFields = new SortField[orderHints.size()];

            for(int i = 0; i < orderHints.size(); i++) {

                OrderHint orderHint = orderHints.get(i);

                switch(orderHint.getSortOrder()) {

                case ASCENDING:

                    sortFields[i] = new SortField(orderHint.getPropertyName(), type, true);

                    break;

                case DESCENDING:

                default:

                    sortFields[i] = new SortField(orderHint.getPropertyName(), type, false);

                }

            }

            sort.setSort(sortFields);

            fullTextQuery.setSort(sort);

        }

    }

    /**

     * @param hql

     * @param orderHints

     */

    protected void addOrder(StringBuilder hql, String alias, List<OrderHint> orderHints) {

        boolean orderByAdded = false;

        String fieldPrefix = "";

        if(alias != null){

            fieldPrefix = alias + ".";

        }

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

            for(OrderHint oh : orderHints){

                if(oh != null){

                    if(!orderByAdded){

                        hql.append(" order by ");

                    }

                    hql.append(fieldPrefix + oh.toHql() + (orderByAdded ? ", ": " "));

                    orderByAdded = true;

                }

            }

        }

    }

   // ---------------------------- //

}