View Javadoc

1   /**
2    * Copyright (c) 2008-2011, 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  
17  package org.yaml.snakeyaml.constructor;
18  
19  import java.util.List;
20  
21  import junit.framework.TestCase;
22  
23  import org.yaml.snakeyaml.Yaml;
24  import org.yaml.snakeyaml.nodes.Node;
25  import org.yaml.snakeyaml.nodes.ScalarNode;
26  import org.yaml.snakeyaml.nodes.SequenceNode;
27  import org.yaml.snakeyaml.nodes.Tag;
28  
29  /**
30   * Example to process a family of tags with the same prefix with one constructor
31   * (PrefixConstruct)
32   */
33  public class PrefixConstructorTest extends TestCase {
34  
35      @SuppressWarnings("unchecked")
36      public void test1() {
37          Yaml yaml = new Yaml(new CustomConstructor());
38          String input = "- !org.yaml.Foo 123\n- !org.yaml.Bar 456\n- !org.yaml.Exact 789\n- !Immutable [aaa, bbb]";
39          List<Extra> list = (List<Extra>) yaml.load(input);
40          assertEquals(4, list.size());
41          Extra foo = list.get(0);
42          assertEquals("Foo", foo.getName());
43          assertEquals("123", foo.getValue());
44          //
45          Extra bar = list.get(1);
46          assertEquals("Bar", bar.getName());
47          assertEquals("456", bar.getValue());
48          //
49          Extra item = list.get(2);
50          assertEquals("Item", item.getName());
51          assertEquals("789", item.getValue());
52          //
53          Extra immut = list.get(3);
54          assertEquals("aaa", immut.getName());
55          assertEquals("bbb", immut.getValue());
56      }
57  
58      private class CustomConstructor extends SafeConstructor {
59          public CustomConstructor() {
60              // define tags which begin with !org.yaml.
61              String prefix = "!org.yaml.";
62              this.yamlMultiConstructors.put(prefix, new PrefixConstruct(prefix,
63                      CustomConstructor.this));
64              this.yamlConstructors.put(null, new ConstructUnknown(CustomConstructor.this));
65              this.yamlConstructors.put(new Tag("!org.yaml.Exact"), new ExactConstruct(
66                      CustomConstructor.this));
67          }
68      }
69  
70      /**
71       * Process tags which start with '!org.yaml.'
72       */
73      private class PrefixConstruct extends AbstractConstruct {
74          private String prefix;
75          private BaseConstructor con;
76  
77          public PrefixConstruct(String prefix, BaseConstructor con) {
78              this.prefix = prefix;
79              this.con = con;
80          }
81  
82          public Object construct(Node node) {
83              String suffix = node.getTag().getValue().substring(prefix.length());
84              return new Extra(suffix, con.constructScalar((ScalarNode) node).toString());
85          }
86      }
87  
88      /**
89       * This has more priority then PrefixConstruct
90       */
91      private class ExactConstruct extends AbstractConstruct {
92          private BaseConstructor con;
93  
94          public ExactConstruct(BaseConstructor con) {
95              this.con = con;
96          }
97  
98          public Object construct(Node node) {
99              return new Extra("Item", con.constructScalar((ScalarNode) node).toString());
100         }
101     }
102 
103     /**
104      * Process unrecognised tags
105      */
106     private class ConstructUnknown extends AbstractConstruct {
107         private BaseConstructor con;
108 
109         public ConstructUnknown(BaseConstructor con) {
110             this.con = con;
111         }
112 
113         @SuppressWarnings("unchecked")
114         public Object construct(Node node) {
115             List<String> list = (List<String>) con.constructSequence((SequenceNode) node);
116             return new Extra(list.get(0), list.get(1));
117         }
118     }
119 
120     private class Extra {
121         private String name;
122         private String value;
123 
124         public Extra(String name, String value) {
125             this.name = name;
126             this.value = value;
127         }
128 
129         public String getValue() {
130             return value;
131         }
132 
133         public String getName() {
134             return name;
135         }
136     }
137 }