001 /**
002 * GRANITE DATA SERVICES
003 * Copyright (C) 2006-2013 GRANITE DATA SERVICES S.A.S.
004 *
005 * This file is part of the Granite Data Services Platform.
006 *
007 * Granite Data Services is free software; you can redistribute it and/or
008 * modify it under the terms of the GNU Lesser General Public
009 * License as published by the Free Software Foundation; either
010 * version 2.1 of the License, or (at your option) any later version.
011 *
012 * Granite Data Services is distributed in the hope that it will be useful,
013 * but WITHOUT ANY WARRANTY; without even the implied warranty of
014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
015 * General Public License for more details.
016 *
017 * You should have received a copy of the GNU Lesser General Public
018 * License along with this library; if not, write to the Free Software
019 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
020 * USA, or see <http://www.gnu.org/licenses/>.
021 */
022 package org.granite.tide.spring.data;
023
024 import java.beans.BeanInfo;
025 import java.beans.Introspector;
026 import java.beans.PropertyDescriptor;
027 import java.util.ArrayList;
028 import java.util.List;
029
030 import javax.persistence.criteria.CriteriaBuilder;
031 import javax.persistence.criteria.CriteriaQuery;
032 import javax.persistence.criteria.Path;
033 import javax.persistence.criteria.Predicate;
034 import javax.persistence.criteria.Root;
035 import javax.persistence.metamodel.Attribute;
036 import javax.persistence.metamodel.ManagedType;
037 import javax.persistence.metamodel.Metamodel;
038
039 import org.springframework.data.jpa.domain.Specification;
040
041 public class FilterExampleSpecification<T> implements Specification<T> {
042
043 private Metamodel metamodel;
044 private Object filter;
045
046 private FilterExampleSpecification(Metamodel metamodel, Object filter) {
047 this.metamodel = metamodel;
048 this.filter = filter;
049 }
050
051 public static <T> FilterExampleSpecification<T> byExample(Metamodel metamodel, Object filter) {
052 return new FilterExampleSpecification<T>(metamodel, filter);
053 }
054
055 public Predicate toPredicate(Root<T> root, CriteriaQuery<?> query, CriteriaBuilder builder) {
056 List<Predicate> predicates = new ArrayList<Predicate>();
057
058 applyAttributes(predicates, root, builder, metamodel.entity(filter.getClass()), filter);
059
060 if (predicates.size() > 0)
061 return builder.and(predicates.toArray(new Predicate[predicates.size()]));
062
063 return null;
064 }
065
066 private void applyAttributes(List<Predicate> predicates, Path<?> root, CriteriaBuilder builder, ManagedType<?> filterType, Object filter) {
067 // Query by example : the filter is of the same type as the entity
068 PropertyDescriptor[] pds = null;
069 try {
070 // Query by bean filter
071 BeanInfo info = Introspector.getBeanInfo(filter.getClass());
072 pds = info.getPropertyDescriptors();
073 }
074 catch (Exception e) {
075 throw new RuntimeException("Could not introspect filter bean", e);
076 }
077
078 for (PropertyDescriptor pd : pds) {
079 if (pd.getReadMethod().isAnnotationPresent(FilterMapping.class) && pd.getReadMethod().getAnnotation(FilterMapping.class).mode() == FilterMode.EXCLUDE)
080 continue;
081
082 Attribute<?, ?> attribute = filterType.getAttribute(pd.getName());
083 if (attribute == null)
084 continue;
085
086 if (attribute.getPersistentAttributeType() == Attribute.PersistentAttributeType.EMBEDDED) {
087 // Visit embedded elements recursively
088 try {
089 Object embedded = pd.getReadMethod().invoke(filter);
090 if (embedded != null) {
091 ManagedType<?> embeddedType = metamodel.embeddable(attribute.getJavaType());
092 applyAttributes(predicates, root.get(pd.getName()), builder, embeddedType, embedded);
093 }
094 }
095 catch (Exception e) {
096 throw new RuntimeException("Could not get filter property " + pd.getName(), e);
097 }
098
099 continue;
100 }
101
102 if (pd.getWriteMethod() == null || attribute.getPersistentAttributeType() != Attribute.PersistentAttributeType.BASIC)
103 continue;
104
105 Object value = null;
106 try {
107 value = pd.getReadMethod().invoke(filter);
108 }
109 catch (Exception e) {
110 throw new RuntimeException("Could not get filter property " + pd.getName(), e);
111 }
112
113 Predicate predicate = FilterSpecUtil.buildPredicate(root, builder, pd.getReadMethod().getReturnType(), pd.getName(), value);
114 if (predicate != null)
115 predicates.add(predicate);
116 }
117 }
118 }