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 javax.persistence.criteria.CriteriaBuilder;
024    import javax.persistence.criteria.Path;
025    import javax.persistence.criteria.Predicate;
026    
027    
028    public class FilterSpecUtil {
029    
030            public static Predicate buildPredicate(Path<?> root, CriteriaBuilder builder, Class<?> type, String key, Object value) {
031                    if (value == null)
032                            return null;
033                    
034                    if (type == null)
035                            type = value.getClass();
036                    
037                    if (type == String.class && value.toString().trim().length() == 0)
038                            return null;
039                    
040                    if (value instanceof String)
041                            return builder.like(root.get(key).as(String.class), "%" + value + "%");
042                    
043                    return builder.equal(root.get(key).as(type), value);
044            }
045    }