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1   /**
2    * Copyright 2005-2014 The Kuali Foundation
3    *
4    * Licensed under the Educational Community License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    *
8    * http://www.opensource.org/licenses/ecl2.php
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  package org.kuali.rice.core.api.criteria;
17  
18  import org.kuali.rice.core.api.mo.ModelBuilder;
19  
20  import java.io.Serializable;
21  
22  /**
23   * This class works withe the lookup framework to customize a query.  It currently can do the following things:
24   *
25   * <ul>
26   *  <li>transform/remove predicates</li>
27   *  <li>transform/remove query results</li>
28   * </ul>
29   *
30   * <p>
31   * The predicate transform will applied to the predicates in the incoming query yielding a
32   * a predicate.  If the predicate does not need to be transformed then the function can return the
33   * incoming argument.  If the predicate should be removed the transform should return null.
34   * This is a way to remove or change a predicate before the query is executed.
35   * This is a good way to add new predicates to a query or to limit the result of the query before
36   * it is executed. Transforms also allow a predicate referencing a property path that does not exist
37   * on database mapped object to be changed to something that is valid.
38   * </p>
39   *
40   * <p>
41   * The result transform will be applied to the results of the query after the query is executed.
42   * If the result does not need to be transformed then the function can return the
43   * incoming argument. This is a way to remove or change a result after the query is executed.
44   * </p>
45   *
46   * <p>transformers should not have to deal with null items</p>
47   *
48   * @deprecated Use {@link org.kuali.rice.core.api.criteria.Transform} directly
49   */
50  @Deprecated
51  public class LookupCustomizer<T> {
52  
53      //FIXME: add wilcards to make predicate transform more flexible ie. EqualsPredicate to AndPredicate
54      private final Transform<Predicate,Predicate> predicateTransform;
55      private final Transform<T, T> resultTransform;
56  
57      private LookupCustomizer(Builder<T> builder) {
58          this.predicateTransform = builder.getPredicateTransform() != null ? builder.getPredicateTransform() : IndentityTransform.<Predicate, Predicate>getInstance();
59          this.resultTransform = builder.getResultTransform() != null ? builder.getResultTransform() : IndentityTransform.<T, T>getInstance();
60      }
61  
62      public Transform<Predicate, Predicate> getPredicateTransform() {
63          return predicateTransform;
64      }
65  
66      public Transform<T, T> getResultTransform() {
67          return resultTransform;
68      }
69  
70      @Deprecated
71      public static final class Builder<T> implements ModelBuilder, Serializable {
72  
73          private Transform<Predicate, Predicate> predicateTransform;
74          private Transform<T, T> resultTransform;
75  
76          private Builder() {
77  
78          }
79  
80          public static <T> Builder<T> create() {
81              return new Builder<T>();
82          }
83  
84          public Transform<Predicate, Predicate> getPredicateTransform() {
85              return predicateTransform;
86          }
87  
88          public void setPredicateTransform(final Transform<Predicate, Predicate> predicateTransform) {
89              this.predicateTransform = predicateTransform;
90          }
91  
92          public Transform<T, T> getResultTransform() {
93              return resultTransform;
94          }
95  
96          public void setResultTransform(final Transform<T, T> resultTransform) {
97              this.resultTransform = resultTransform;
98          }
99  
100         @Override
101         public LookupCustomizer<T> build() {
102             return new LookupCustomizer<T>(this);
103         }
104     }
105 
106     @Deprecated
107     public interface Transform<P, R> {
108         R apply(P input);
109     }
110 
111     /**
112      * f: x -> x.  This function just returns the passed in parameter.
113      *
114      * @param <I> the type the function acts on.
115      */
116     @Deprecated
117     private static final class IndentityTransform<I> implements Transform<I, I> {
118 
119         @SuppressWarnings("unchecked")
120         private static final Transform INSTANCE = new IndentityTransform();
121 
122         @SuppressWarnings("unchecked")
123         public static <P, R> Transform<P, R> getInstance() {
124             return INSTANCE;
125         }
126 
127         @Override
128         public I apply(final I input) {
129             return input;
130         }
131     }
132 }