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1   /**
2    * Copyright (c) 2008-2012, 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.types;
17  
18  import java.util.ArrayList;
19  import java.util.HashMap;
20  import java.util.List;
21  import java.util.Map;
22  
23  import org.yaml.snakeyaml.DumperOptions;
24  import org.yaml.snakeyaml.DumperOptions.FlowStyle;
25  import org.yaml.snakeyaml.Yaml;
26  import org.yaml.snakeyaml.nodes.Node;
27  import org.yaml.snakeyaml.nodes.Tag;
28  import org.yaml.snakeyaml.representer.Represent;
29  import org.yaml.snakeyaml.representer.Representer;
30  
31  /**
32   * @see http://yaml.org/type/null.html
33   */
34  public class NullTagTest extends AbstractTest {
35  
36      public void testNull() {
37          assertNull("Got: '" + load("---\n") + "'", load("---\n"));
38          assertNull(load("---\n..."));
39          assertNull(load("---\n...\n"));
40          assertNull(load("\n"));
41          assertNull(load(""));
42          assertNull(load(" "));
43          assertNull(load("~"));
44          assertNull(load("---\n~"));
45          assertNull(load("null"));
46          assertNull(load("Null"));
47          assertNull(load("NULL"));
48          assertNull(getMapValue("empty:\n", "empty"));
49          assertNull(getMapValue("canonical: ~", "canonical"));
50          assertNull(getMapValue("english: null", "english"));
51          assertNull(getMapValue("english: Null", "english"));
52          assertNull(getMapValue("english: NULL", "english"));
53          assertEquals("null key", getMapValue("~: null key\n", null));
54      }
55  
56      @SuppressWarnings("unchecked")
57      public void testSequenceNull() {
58          String input = "---\n# This sequence has five\n# entries, two have values.\nsparse:\n  - ~\n  - 2nd entry\n  -\n  - 4th entry\n  - Null\n";
59          List<String> parsed = (List<String>) getMapValue(input, "sparse");
60          assertEquals(5, parsed.size());
61          assertNull(parsed.get(0));
62          assertEquals("2nd entry", parsed.get(1));
63          assertNull("Got: '" + parsed.get(2) + "'", parsed.get(2));
64          assertEquals("4th entry", parsed.get(3));
65          assertNull(parsed.get(4));
66      }
67  
68      public void testNullInMap() {
69          String input = "key1: null\n~: value1";
70          Map<String, Object> parsed = getMap(input);
71          assertEquals(2, parsed.size());
72          assertTrue(parsed.containsKey(null));
73          Object value1 = parsed.get(null);
74          assertEquals("value1", value1);
75          //
76          assertNull(parsed.get("key1"));
77          //
78          assertFalse(getMap("key2: value2").containsKey(null));
79      }
80  
81      public void testNullShorthand() {
82          assertNull(getMapValue("nothing: !!null null", "nothing"));
83      }
84  
85      public void testNullTag() {
86          assertNull(getMapValue("nothing: !<tag:yaml.org,2002:null> null", "nothing"));
87      }
88  
89      public void testNullOut() {
90          String output = dump(null);
91          assertEquals("null\n", output);
92      }
93  
94      public void testNullOutAsEmpty() {
95          Yaml yaml = new Yaml(new NullRepresenter());
96          String output = yaml.dump(null);
97          assertEquals("", output);
98      }
99  
100     /**
101      * test flow style
102      */
103     public void testNullOutAsEmpty2() {
104         Yaml yaml = new Yaml(new NullRepresenter());
105         Map<String, String> map = new HashMap<String, String>();
106         map.put("aaa", "foo");
107         map.put("bbb", null);
108         String output = yaml.dump(map);
109         assertEquals("{aaa: foo, bbb: !!null ''}\n", output);
110     }
111 
112     /**
113      * test block style
114      */
115     public void testBoolOutAsEmpty3() {
116         DumperOptions options = new DumperOptions();
117         options.setDefaultFlowStyle(FlowStyle.BLOCK);
118         Yaml yaml = new Yaml(new NullRepresenter(), options);
119         Map<String, String> map = new HashMap<String, String>();
120         map.put("aaa", "foo");
121         map.put("bbb", null);
122         String output = yaml.dump(map);
123         assertEquals("aaa: foo\nbbb:\n", output);
124     }
125 
126     private class NullRepresenter extends Representer {
127         public NullRepresenter() {
128             super();
129             // null representer is exceptional and it is stored as an instance
130             // variable.
131             this.nullRepresenter = new RepresentNull();
132         }
133 
134         private class RepresentNull implements Represent {
135             public Node representData(Object data) {
136                 // possible values are here http://yaml.org/type/null.html
137                 return representScalar(Tag.NULL, "");
138             }
139         }
140     }
141 
142     public void testNoAnchors() {
143         List<String> list = new ArrayList<String>(3);
144         list.add(null);
145         list.add("value");
146         list.add(null);
147         Yaml yaml = new Yaml();
148         String output = yaml.dump(list);
149         assertEquals("Null values must not get anchors and aliases.", "[null, value, null]\n",
150                 output);
151     }
152 }