001 /*
002 * Java GPX Library (jpx-3.1.0).
003 * Copyright (c) 2016-2023 Franz Wilhelmstötter
004 *
005 * Licensed under the Apache License, Version 2.0 (the "License");
006 * you may not use this file except in compliance with the License.
007 * You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 *
017 * Author:
018 * Franz Wilhelmstötter (franz.wilhelmstoetter@gmail.com)
019 */
020 package io.jenetics.jpx;
021
022 import static java.lang.String.format;
023 import static java.util.Objects.hash;
024 import static java.util.Objects.requireNonNull;
025 import static io.jenetics.jpx.Format.parseURI;
026
027 import java.io.DataInput;
028 import java.io.DataOutput;
029 import java.io.IOException;
030 import java.io.InvalidObjectException;
031 import java.io.ObjectInputStream;
032 import java.io.Serial;
033 import java.io.Serializable;
034 import java.net.URI;
035 import java.util.Objects;
036 import java.util.Optional;
037
038 /**
039 * Represents a link to an external resource (Web page, digital photo, video
040 * clip, etc) with additional information.
041 *
042 * @author <a href="mailto:franz.wilhelmstoetter@gmail.com">Franz Wilhelmstötter</a>
043 * @version 1.2
044 * @since 1.0
045 */
046 public final class Link implements Serializable {
047
048 @Serial
049 private static final long serialVersionUID = 2L;
050
051 private final URI _href;
052 private final String _text;
053 private final String _type;
054
055 /**
056 * Create a new {@code Link} object with the given parameters.
057 *
058 * @param href the hyperlink (mandatory)
059 * @param text the text of the hyperlink (optional)
060 * @param type the mime type of the content, e.g. {@code image/jpeg}
061 * (optional)
062 * @throws NullPointerException if the given {@code href} is {@code null}
063 */
064 private Link(final URI href, final String text, final String type) {
065 _href = requireNonNull(href);
066 _text = text;
067 _type = type;
068 }
069
070 /**
071 * Return the hyperlink.
072 *
073 * @return the hyperlink
074 */
075 public URI getHref() {
076 return _href;
077 }
078
079 /**
080 * Return the hyperlink text.
081 *
082 * @return the hyperlink text
083 */
084 public Optional<String> getText() {
085 return Optional.ofNullable(_text);
086 }
087
088 /**
089 * Return the mime type of the hyperlink
090 *
091 * @return the mime type
092 */
093 public Optional<String> getType() {
094 return Optional.ofNullable(_type);
095 }
096
097 @Override
098 public int hashCode() {
099 return hash(_href, _text, _type);
100 }
101
102 @Override
103 public boolean equals(final Object obj) {
104 return obj == this ||
105 obj instanceof Link link &&
106 Objects.equals(link._href, _href) &&
107 Objects.equals(link._text, _text) &&
108 Objects.equals(link._type, _type);
109 }
110
111 @Override
112 public String toString() {
113 return format("Link[%s, text=%s, type=%s]", _href, _text, _type);
114 }
115
116
117 /* *************************************************************************
118 * Static object creation methods
119 * ************************************************************************/
120
121 /**
122 * Create a new {@code Link} object with the given parameters.
123 *
124 * @param href the hyperlink (mandatory)
125 * @param text the text of the hyperlink (optional)
126 * @param type the mime type of the content, e.g. {@code image/jpeg}
127 * (optional)
128 * @return a new {@code Link} object with the given parameters
129 * @throws NullPointerException if the given {@code href} is {@code null}
130 */
131 public static Link of(final URI href, final String text, final String type) {
132 return new Link(href, text, type);
133 }
134
135 /**
136 * Create a new {@code Link} object with the given parameters.
137 *
138 * @param href the hyperlink (mandatory)
139 * @param text the text of the hyperlink (optional)
140 * @param type the mime type of the content, e.g. {@code image/jpeg}
141 * (optional)
142 * @return a new {@code Link} object with the given parameters
143 * @throws NullPointerException if the given {@code href} is {@code null}
144 * @throws IllegalArgumentException if the given {@code href} is not a valid
145 * URL
146 */
147 public static Link of(final String href, final String text, final String type) {
148 return new Link(parseURI(requireNonNull(href)), text, type);
149 }
150
151 /**
152 * Create a new {@code Link} object with the given {@code href}.
153 *
154 * @param href the hyperlink (mandatory)
155 * @return a new {@code Link} object with the given {@code href}
156 * @throws NullPointerException if the given {@code href} is {@code null}
157 */
158 public static Link of(final URI href) {
159 return new Link(href, null, null);
160 }
161
162 /**
163 * Create a new {@code Link} object with the given {@code href}.
164 *
165 * @param href the hyperlink (mandatory)
166 * @return a new {@code Link} object with the given {@code href}
167 * @throws NullPointerException if the given {@code href} is {@code null}
168 * @throws IllegalArgumentException if the given {@code href} is not a valid
169 * URL
170 */
171 public static Link of(final String href) {
172 return new Link(parseURI(requireNonNull(href)), null, null);
173 }
174
175 /* *************************************************************************
176 * Java object serialization
177 * ************************************************************************/
178
179 @Serial
180 private Object writeReplace() {
181 return new SerialProxy(SerialProxy.LINK, this);
182 }
183
184 @Serial
185 private void readObject(final ObjectInputStream stream)
186 throws InvalidObjectException
187 {
188 throw new InvalidObjectException("Serialization proxy required.");
189 }
190
191 void write(final DataOutput out) throws IOException {
192 IO.writeString(_href.toString(), out);
193 IO.writeNullableString(_text, out);
194 IO.writeNullableString(_type, out);
195 }
196
197 static Link read(final DataInput in) throws IOException {
198 return new Link(
199 parseURI((IO.readString(in))),
200 IO.readNullableString(in),
201 IO.readNullableString(in)
202 );
203 }
204
205 /* *************************************************************************
206 * XML stream object serialization
207 * ************************************************************************/
208
209 static final XMLWriter<Link> WRITER = XMLWriter.elem("link",
210 XMLWriter.attr("href").map(link -> link._href),
211 XMLWriter.elem("text").map(link -> link._text),
212 XMLWriter.elem("type").map(link -> link._type)
213 );
214
215 static final XMLReader<Link> READER = XMLReader.elem(
216 v -> Link.of((URI)v[0], (String)v[1], (String)v[2]),
217 "link",
218 XMLReader.attr("href").map(Format::parseURI),
219 XMLReader.elem("text"),
220 XMLReader.elem("type")
221 );
222
223 }
|