001    /*
002      GRANITE DATA SERVICES
003      Copyright (C) 2011 GRANITE DATA SERVICES S.A.S.
004    
005      This file is part of Granite Data Services.
006    
007      Granite Data Services is free software; you can redistribute it and/or modify
008      it under the terms of the GNU Library General Public License as published by
009      the Free Software Foundation; either version 2 of the License, or (at your
010      option) any later version.
011    
012      Granite Data Services is distributed in the hope that it will be useful, but
013      WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
014      FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License
015      for more details.
016    
017      You should have received a copy of the GNU Library General Public License
018      along with this library; if not, see <http://www.gnu.org/licenses/>.
019    */
020    
021    package org.granite.tide.spring.data;
022    
023    import java.util.ArrayList;
024    import java.util.List;
025    import java.util.Map;
026    import java.util.Map.Entry;
027    
028    import javax.persistence.criteria.CriteriaBuilder;
029    import javax.persistence.criteria.CriteriaQuery;
030    import javax.persistence.criteria.Predicate;
031    import javax.persistence.criteria.Root;
032    
033    import org.springframework.data.jpa.domain.Specification;
034    
035    public class FilterMapSpecification<T> implements Specification<T> {
036            
037            private Map<String, Object> filter;
038            
039            private FilterMapSpecification(Map<String, Object> filter) {
040                    this.filter = filter;
041            }
042            
043            public static <T> FilterMapSpecification<T> byMap(Map<String, Object> filter) {
044                    return new FilterMapSpecification<T>(filter);
045            }
046    
047            public Predicate toPredicate(Root<T> root, CriteriaQuery<?> query, CriteriaBuilder builder) {
048                    List<Predicate> predicates = new ArrayList<Predicate>();
049                    
050                    // Query by map filter
051                    for (Entry<String, Object> entry : filter.entrySet()) {
052                            if (root.get(entry.getKey()) == null)
053                                    throw new RuntimeException("Invalid filter mapping, path: " + entry.getKey());
054                            
055                            Predicate predicate = FilterSpecUtil.buildPredicate(root, builder, null, entry.getKey(), entry.getValue());
056                            if (predicate != null)
057                                    predicates.add(predicate);
058                    }
059                    
060                    if (predicates.size() > 0)
061                            return builder.and(predicates.toArray(new Predicate[predicates.size()]));
062                    
063                    return null;
064            }               
065    }