1 /*
2 * Copyright 2012-2013 smartics, Kronseder & Reiner GmbH
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 de.smartics.properties.spi.core.metadata;
17
18 import java.util.HashMap;
19 import java.util.Locale;
20 import java.util.Map;
21
22 import javax.annotation.concurrent.NotThreadSafe;
23
24 import org.apache.commons.lang.builder.ToStringBuilder;
25
26 import de.smartics.properties.api.core.domain.PropertiesContext;
27 import de.smartics.properties.api.core.domain.PropertyComment;
28 import de.smartics.properties.api.core.domain.PropertyDescriptor;
29 import de.smartics.properties.spi.core.metadata.comment.PropertyCommentParser;
30
31 /**
32 * Proxy to load property comments on demand.
33 */
34 @NotThreadSafe
35 public final class PropertyCommentProxy implements PropertyCommentProvider
36 {
37 // ********************************* Fields *********************************
38
39 // --- constants ------------------------------------------------------------
40
41 /**
42 * The class version identifier.
43 * <p>
44 * The value of this constant is {@value}.
45 * </p>
46 */
47 private static final long serialVersionUID = 1L;
48
49 // --- members --------------------------------------------------------------
50
51 /**
52 * The properties context to fetch information from the META-INF folder. May
53 * be <code>null</code>.
54 *
55 * @serial
56 */
57 private final PropertiesContext context;
58
59 /**
60 * The cached comments.
61 *
62 * @serial
63 */
64 private final Map<Locale, PropertyComment> comments;
65
66 // ****************************** Initializer *******************************
67
68 // ****************************** Constructors ******************************
69
70 /**
71 * Default constructor. If the {@code context} is <code>null</code>, the proxy
72 * may only server {@link PropertyComment#EMPTY_COMMENT empty property
73 * comment} instances.
74 *
75 * @param context the properties context to fetch information from the
76 * <code>META-INF</code> folder.
77 */
78 public PropertyCommentProxy(final PropertiesContext context)
79 {
80 this.context = context;
81 this.comments =
82 (context != null) ? new HashMap<Locale, PropertyComment>() : null;
83 }
84
85 // ****************************** Inner Classes *****************************
86
87 // ********************************* Methods ********************************
88
89 // --- init -----------------------------------------------------------------
90
91 // --- get&set --------------------------------------------------------------
92
93 // --- business -------------------------------------------------------------
94
95 /**
96 * {@inheritDoc}
97 *
98 * @impl Due to the very close relationship between the proxy and the property
99 * descriptor, the proxy cannot get access to its descriptor on creation
100 * time. The reason for the requirement that each invocation provides
101 * the same property descriptor is caching: the comments are cached with
102 * the locale as key. The property descriptor is not taken into account.
103 * This is okay since this implementation is private and only used
104 * internally by the PropertyMetaData class.
105 */
106 @Override
107 public PropertyComment getComment(
108 final PropertyDescriptor propertyDescriptor, final Locale locale)
109 {
110 if (context != null)
111 {
112 final PropertyCommentParser parser = new PropertyCommentParser(context);
113 PropertyComment comment = comments.get(locale);
114 if (comment == null)
115 {
116 comment = parser.parse(propertyDescriptor, locale);
117 comments.put(locale, comment);
118 }
119
120 return comment;
121 }
122
123 return PropertyComment.EMPTY_COMMENT;
124 }
125
126 // --- object basics --------------------------------------------------------
127
128 /**
129 * Returns the string representation of the object.
130 *
131 * @return the string representation of the object.
132 */
133 @Override
134 public String toString()
135 {
136 return ToStringBuilder.reflectionToString(this);
137 }
138 }