1/*
2 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26package java.text;
27
28import java.io.InvalidObjectException;
29import java.io.Serializable;
30import java.util.HashMap;
31import java.util.Map;
32import java.util.Set;
33
34/**
35 * An {@code AttributedCharacterIterator} allows iteration through both text and
36 * related attribute information.
37 *
38 * <p>
39 * An attribute is a key/value pair, identified by the key.  No two
40 * attributes on a given character can have the same key.
41 *
42 * <p>The values for an attribute are immutable, or must not be mutated
43 * by clients or storage.  They are always passed by reference, and not
44 * cloned.
45 *
46 * <p>A <em>run with respect to an attribute</em> is a maximum text range for
47 * which:
48 * <ul>
49 * <li>the attribute is undefined or {@code null} for the entire range, or
50 * <li>the attribute value is defined and has the same non-{@code null} value for the
51 *     entire range.
52 * </ul>
53 *
54 * <p>A <em>run with respect to a set of attributes</em> is a maximum text range for
55 * which this condition is met for each member attribute.
56 *
57 * <p>When getting a run with no explicit attributes specified (i.e.,
58 * calling {@link #getRunStart()} and {@link #getRunLimit()}), any
59 * contiguous text segments having the same attributes (the same set
60 * of attribute/value pairs) are treated as separate runs if the
61 * attributes have been given to those text segments separately.
62 *
63 * <p>The returned indexes are limited to the range of the iterator.
64 *
65 * <p>The returned attribute information is limited to runs that contain
66 * the current character.
67 *
68 * <p>
69 * Attribute keys are instances of {@link AttributedCharacterIterator.Attribute} and its
70 * subclasses, such as {@link java.awt.font.TextAttribute}.
71 *
72 * @see AttributedCharacterIterator.Attribute
73 * @see java.awt.font.TextAttribute
74 * @see AttributedString
75 * @see Annotation
76 * @since 1.2
77 */
78
79public interface AttributedCharacterIterator extends CharacterIterator {
80
81    /**
82     * Defines attribute keys that are used to identify text attributes. These
83     * keys are used in {@code AttributedCharacterIterator} and {@code AttributedString}.
84     * @see AttributedCharacterIterator
85     * @see AttributedString
86     * @since 1.2
87     */
88
89    public static class Attribute implements Serializable {
90
91        /**
92         * The name of this {@code Attribute}. The name is used primarily by {@code readResolve}
93         * to look up the corresponding predefined instance when deserializing
94         * an instance.
95         * @serial
96         */
97        private String name;
98
99        // table of all instances in this class, used by readResolve
100        private static final Map<String, Attribute> instanceMap = new HashMap<>(7);
101
102        /**
103         * Constructs an {@code Attribute} with the given name.
104         *
105         * @param name the name of {@code Attribute}
106         */
107        protected Attribute(String name) {
108            this.name = name;
109            if (this.getClass() == Attribute.class) {
110                instanceMap.put(name, this);
111            }
112        }
113
114        /**
115         * Compares two objects for equality. This version only returns true
116         * for {@code x.equals(y)} if {@code x} and {@code y} refer
117         * to the same object, and guarantees this for all subclasses.
118         */
119        public final boolean equals(Object obj) {
120            return super.equals(obj);
121        }
122
123        /**
124         * Returns a hash code value for the object. This version is identical to
125         * the one in {@code Object}, but is also final.
126         */
127        public final int hashCode() {
128            return super.hashCode();
129        }
130
131        /**
132         * Returns a string representation of the object. This version returns the
133         * concatenation of class name, {@code "("}, a name identifying the attribute
134         * and {@code ")"}.
135         */
136        public String toString() {
137            return getClass().getName() + "(" + name + ")";
138        }
139
140        /**
141         * Returns the name of the attribute.
142         *
143         * @return the name of {@code Attribute}
144         */
145        protected String getName() {
146            return name;
147        }
148
149        /**
150         * Resolves instances being deserialized to the predefined constants.
151         *
152         * @return the resolved {@code Attribute} object
153         * @throws InvalidObjectException if the object to resolve is not
154         *                                an instance of {@code Attribute}
155         */
156        protected Object readResolve() throws InvalidObjectException {
157            if (this.getClass() != Attribute.class) {
158                throw new InvalidObjectException("subclass didn't correctly implement readResolve");
159            }
160
161            Attribute instance = instanceMap.get(getName());
162            if (instance != null) {
163                return instance;
164            } else {
165                throw new InvalidObjectException("unknown attribute name");
166            }
167        }
168
169        /**
170         * Attribute key for the language of some text.
171         * <p> Values are instances of {@link java.util.Locale Locale}.
172         * @see java.util.Locale
173         */
174        public static final Attribute LANGUAGE = new Attribute("language");
175
176        /**
177         * Attribute key for the reading of some text. In languages where the written form
178         * and the pronunciation of a word are only loosely related (such as Japanese),
179         * it is often necessary to store the reading (pronunciation) along with the
180         * written form.
181         * <p>Values are instances of {@link Annotation} holding instances of {@link String}.
182         *
183         * @see Annotation
184         * @see java.lang.String
185         */
186        public static final Attribute READING = new Attribute("reading");
187
188        /**
189         * Attribute key for input method segments. Input methods often break
190         * up text into segments, which usually correspond to words.
191         * <p>Values are instances of {@link Annotation} holding a {@code null} reference.
192         * @see Annotation
193         */
194        public static final Attribute INPUT_METHOD_SEGMENT = new Attribute("input_method_segment");
195
196        // make sure the serial version doesn't change between compiler versions
197        private static final long serialVersionUID = -9142742483513960612L;
198
199    };
200
201    /**
202     * Returns the index of the first character of the run
203     * with respect to all attributes containing the current character.
204     *
205     * <p>Any contiguous text segments having the same attributes (the
206     * same set of attribute/value pairs) are treated as separate runs
207     * if the attributes have been given to those text segments separately.
208     *
209     * @return the index of the first character of the run
210     */
211    public int getRunStart();
212
213    /**
214     * Returns the index of the first character of the run
215     * with respect to the given {@code attribute} containing the current character.
216     *
217     * @param attribute the desired attribute.
218     * @return the index of the first character of the run
219     */
220    public int getRunStart(Attribute attribute);
221
222    /**
223     * Returns the index of the first character of the run
224     * with respect to the given {@code attributes} containing the current character.
225     *
226     * @param attributes a set of the desired attributes.
227     * @return the index of the first character of the run
228     */
229    public int getRunStart(Set<? extends Attribute> attributes);
230
231    /**
232     * Returns the index of the first character following the run
233     * with respect to all attributes containing the current character.
234     *
235     * <p>Any contiguous text segments having the same attributes (the
236     * same set of attribute/value pairs) are treated as separate runs
237     * if the attributes have been given to those text segments separately.
238     *
239     * @return the index of the first character following the run
240     */
241    public int getRunLimit();
242
243    /**
244     * Returns the index of the first character following the run
245     * with respect to the given {@code attribute} containing the current character.
246     *
247     * @param attribute the desired attribute
248     * @return the index of the first character following the run
249     */
250    public int getRunLimit(Attribute attribute);
251
252    /**
253     * Returns the index of the first character following the run
254     * with respect to the given {@code attributes} containing the current character.
255     *
256     * @param attributes a set of the desired attributes
257     * @return the index of the first character following the run
258     */
259    public int getRunLimit(Set<? extends Attribute> attributes);
260
261    /**
262     * Returns a map with the attributes defined on the current
263     * character.
264     *
265     * @return a map with the attributes defined on the current character
266     */
267    public Map<Attribute,Object> getAttributes();
268
269    /**
270     * Returns the value of the named {@code attribute} for the current character.
271     * Returns {@code null} if the {@code attribute} is not defined.
272     *
273     * @param attribute the desired attribute
274     * @return the value of the named {@code attribute} or {@code null}
275     */
276    public Object getAttribute(Attribute attribute);
277
278    /**
279     * Returns the keys of all attributes defined on the
280     * iterator's text range. The set is empty if no
281     * attributes are defined.
282     *
283     * @return the keys of all attributes
284     */
285    public Set<Attribute> getAllAttributeKeys();
286};
287