1 /**
2  * Copyright (c) 2008, http://www.snakeyaml.org
3  *
4  * Licensed under the Apache 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.apache.org/licenses/LICENSE-2.0
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.yaml.snakeyaml.issues.issue94;
17 
18 import static org.junit.Assert.assertEquals;
19 
20 import org.junit.Test;
21 import org.yaml.snakeyaml.Yaml;
22 import org.yaml.snakeyaml.constructor.AbstractConstruct;
23 import org.yaml.snakeyaml.constructor.Construct;
24 import org.yaml.snakeyaml.constructor.Constructor;
25 import org.yaml.snakeyaml.nodes.Node;
26 
27 public class ChangeRuntimeClassTest {
28 
29     @Test
testWithGlobalTag()30     public void testWithGlobalTag() {
31         String yamlText = "!!org.yaml.snakeyaml.issues.issue94.Entity\n" + "name: Matt\n"
32                 + "nickName: Java\n";
33 
34         // Now here that I would like to somehow intercept the constructor of
35         // SnakeYaml and give it
36         // an fresh instance of EntityLoadingProxy(); based on today's
37         // temperature, so to speak...
38         // that is un-preditable statically which proxy I will give it.
39 
40         Yaml yaml = new Yaml(new MyConstructor());
41 
42         Entity loadedEntity = null;
43         loadedEntity = (Entity) yaml.load(yamlText);
44 
45         assertEquals("Matt", loadedEntity.getName());
46 
47         // The expectation below is from having intercepted setNickName() with
48         // the artifical subclass and
49         // performed the calculation.
50         assertEquals("JJ-Java", loadedEntity.getNickName());
51         assertEquals(EntityLoadingProxy.class, loadedEntity.getClass());
52     }
53 
54     @Test
testNoTag()55     public void testNoTag() {
56         String yamlText = "name: Matt\n" + "nickName: Java\n";
57         Yaml yaml = new Yaml(new MyConstructor(Entity.class));
58         Entity loadedEntity = null;
59         loadedEntity = (Entity) yaml.load(yamlText);
60         assertEquals("Matt", loadedEntity.getName());
61         assertEquals("JJ-Java", loadedEntity.getNickName());
62     }
63 
64     /**
65      * @see Constructor.ConstructYamlObject
66      */
67     private class MyConstructor extends Constructor {
MyConstructor()68         public MyConstructor() {
69             super();
70             this.yamlConstructors.put(null, new ConstructProxy());
71         }
72 
MyConstructor(Class<?> clazz)73         public MyConstructor(Class<?> clazz) {
74             super(clazz);
75             this.yamlConstructors.put(null, new ConstructProxy());
76         }
77 
78         private class ConstructProxy extends AbstractConstruct {
getConstructor(Node node)79             private Construct getConstructor(Node node) {
80                 Class<?> cl = getClassForNode(node);
81                 if (cl.equals(Entity.class) && true) {
82                     // today's temperature is high :)
83                     cl = EntityLoadingProxy.class;
84                 }
85                 node.setType(cl);
86                 // call the constructor as if the runtime class is defined
87                 Construct constructor = yamlClassConstructors.get(node.getNodeId());
88                 return constructor;
89             }
90 
construct(Node node)91             public Object construct(Node node) {
92                 return getConstructor(node).construct(node);
93             }
94         }
95     }
96 }
97