001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. 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
018 package org.apache.commons.math3.geometry;
019
020 import java.text.FieldPosition;
021 import java.text.NumberFormat;
022 import java.text.ParsePosition;
023 import java.util.Locale;
024
025 import org.apache.commons.math3.util.CompositeFormat;
026 import org.apache.commons.math3.exception.MathParseException;
027
028 /**
029 * Formats a vector in components list format "{x; y; ...}".
030 * <p>The prefix and suffix "{" and "}" and the separator "; " can be replaced by
031 * any user-defined strings. The number format for components can be configured.</p>
032 * <p>White space is ignored at parse time, even if it is in the prefix, suffix
033 * or separator specifications. So even if the default separator does include a space
034 * character that is used at format time, both input string "{1;1;1}" and
035 * " { 1 ; 1 ; 1 } " will be parsed without error and the same vector will be
036 * returned. In the second case, however, the parse position after parsing will be
037 * just after the closing curly brace, i.e. just before the trailing space.</p>
038 *
039 * @param <S> Type of the space.
040 * @version $Id: VectorFormat.java 1416643 2012-12-03 19:37:14Z tn $
041 * @since 3.0
042 */
043 public abstract class VectorFormat<S extends Space> {
044
045 /** The default prefix: "{". */
046 public static final String DEFAULT_PREFIX = "{";
047
048 /** The default suffix: "}". */
049 public static final String DEFAULT_SUFFIX = "}";
050
051 /** The default separator: ", ". */
052 public static final String DEFAULT_SEPARATOR = "; ";
053
054 /** Prefix. */
055 private final String prefix;
056
057 /** Suffix. */
058 private final String suffix;
059
060 /** Separator. */
061 private final String separator;
062
063 /** Trimmed prefix. */
064 private final String trimmedPrefix;
065
066 /** Trimmed suffix. */
067 private final String trimmedSuffix;
068
069 /** Trimmed separator. */
070 private final String trimmedSeparator;
071
072 /** The format used for components. */
073 private final NumberFormat format;
074
075 /**
076 * Create an instance with default settings.
077 * <p>The instance uses the default prefix, suffix and separator:
078 * "{", "}", and "; " and the default number format for components.</p>
079 */
080 protected VectorFormat() {
081 this(DEFAULT_PREFIX, DEFAULT_SUFFIX, DEFAULT_SEPARATOR,
082 CompositeFormat.getDefaultNumberFormat());
083 }
084
085 /**
086 * Create an instance with a custom number format for components.
087 * @param format the custom format for components.
088 */
089 protected VectorFormat(final NumberFormat format) {
090 this(DEFAULT_PREFIX, DEFAULT_SUFFIX, DEFAULT_SEPARATOR, format);
091 }
092
093 /**
094 * Create an instance with custom prefix, suffix and separator.
095 * @param prefix prefix to use instead of the default "{"
096 * @param suffix suffix to use instead of the default "}"
097 * @param separator separator to use instead of the default "; "
098 */
099 protected VectorFormat(final String prefix, final String suffix,
100 final String separator) {
101 this(prefix, suffix, separator, CompositeFormat.getDefaultNumberFormat());
102 }
103
104 /**
105 * Create an instance with custom prefix, suffix, separator and format
106 * for components.
107 * @param prefix prefix to use instead of the default "{"
108 * @param suffix suffix to use instead of the default "}"
109 * @param separator separator to use instead of the default "; "
110 * @param format the custom format for components.
111 */
112 protected VectorFormat(final String prefix, final String suffix,
113 final String separator, final NumberFormat format) {
114 this.prefix = prefix;
115 this.suffix = suffix;
116 this.separator = separator;
117 trimmedPrefix = prefix.trim();
118 trimmedSuffix = suffix.trim();
119 trimmedSeparator = separator.trim();
120 this.format = format;
121 }
122
123 /**
124 * Get the set of locales for which point/vector formats are available.
125 * <p>This is the same set as the {@link NumberFormat} set.</p>
126 * @return available point/vector format locales.
127 */
128 public static Locale[] getAvailableLocales() {
129 return NumberFormat.getAvailableLocales();
130 }
131
132 /**
133 * Get the format prefix.
134 * @return format prefix.
135 */
136 public String getPrefix() {
137 return prefix;
138 }
139
140 /**
141 * Get the format suffix.
142 * @return format suffix.
143 */
144 public String getSuffix() {
145 return suffix;
146 }
147
148 /**
149 * Get the format separator between components.
150 * @return format separator.
151 */
152 public String getSeparator() {
153 return separator;
154 }
155
156 /**
157 * Get the components format.
158 * @return components format.
159 */
160 public NumberFormat getFormat() {
161 return format;
162 }
163
164 /**
165 * Formats a {@link Vector} object to produce a string.
166 * @param vector the object to format.
167 * @return a formatted string.
168 */
169 public String format(Vector<S> vector) {
170 return format(vector, new StringBuffer(), new FieldPosition(0)).toString();
171 }
172
173 /**
174 * Formats a {@link Vector} object to produce a string.
175 * @param vector the object to format.
176 * @param toAppendTo where the text is to be appended
177 * @param pos On input: an alignment field, if desired. On output: the
178 * offsets of the alignment field
179 * @return the value passed in as toAppendTo.
180 */
181 public abstract StringBuffer format(Vector<S> vector,
182 StringBuffer toAppendTo, FieldPosition pos);
183
184 /**
185 * Formats the coordinates of a {@link Vector} to produce a string.
186 * @param toAppendTo where the text is to be appended
187 * @param pos On input: an alignment field, if desired. On output: the
188 * offsets of the alignment field
189 * @param coordinates coordinates of the object to format.
190 * @return the value passed in as toAppendTo.
191 */
192 protected StringBuffer format(StringBuffer toAppendTo, FieldPosition pos,
193 double ... coordinates) {
194
195 pos.setBeginIndex(0);
196 pos.setEndIndex(0);
197
198 // format prefix
199 toAppendTo.append(prefix);
200
201 // format components
202 for (int i = 0; i < coordinates.length; ++i) {
203 if (i > 0) {
204 toAppendTo.append(separator);
205 }
206 CompositeFormat.formatDouble(coordinates[i], format, toAppendTo, pos);
207 }
208
209 // format suffix
210 toAppendTo.append(suffix);
211
212 return toAppendTo;
213
214 }
215
216 /**
217 * Parses a string to produce a {@link Vector} object.
218 * @param source the string to parse
219 * @return the parsed {@link Vector} object.
220 * @throws MathParseException if the beginning of the specified string
221 * cannot be parsed.
222 */
223 public abstract Vector<S> parse(String source) throws MathParseException;
224
225 /**
226 * Parses a string to produce a {@link Vector} object.
227 * @param source the string to parse
228 * @param pos input/output parsing parameter.
229 * @return the parsed {@link Vector} object.
230 */
231 public abstract Vector<S> parse(String source, ParsePosition pos);
232
233 /**
234 * Parses a string to produce an array of coordinates.
235 * @param dimension dimension of the space
236 * @param source the string to parse
237 * @param pos input/output parsing parameter.
238 * @return coordinates array.
239 */
240 protected double[] parseCoordinates(int dimension, String source, ParsePosition pos) {
241
242 int initialIndex = pos.getIndex();
243 double[] coordinates = new double[dimension];
244
245 // parse prefix
246 CompositeFormat.parseAndIgnoreWhitespace(source, pos);
247 if (!CompositeFormat.parseFixedstring(source, trimmedPrefix, pos)) {
248 return null;
249 }
250
251 for (int i = 0; i < dimension; ++i) {
252
253 // skip whitespace
254 CompositeFormat.parseAndIgnoreWhitespace(source, pos);
255
256 // parse separator
257 if (i > 0) {
258 if (!CompositeFormat.parseFixedstring(source, trimmedSeparator, pos)) {
259 return null;
260 }
261 }
262
263 // skip whitespace
264 CompositeFormat.parseAndIgnoreWhitespace(source, pos);
265
266 // parse coordinate
267 Number c = CompositeFormat.parseNumber(source, format, pos);
268 if (c == null) {
269 // invalid coordinate
270 // set index back to initial, error index should already be set
271 pos.setIndex(initialIndex);
272 return null;
273 }
274
275 // store coordinate
276 coordinates[i] = c.doubleValue();
277
278 }
279
280 // parse suffix
281 CompositeFormat.parseAndIgnoreWhitespace(source, pos);
282 if (!CompositeFormat.parseFixedstring(source, trimmedSuffix, pos)) {
283 return null;
284 }
285
286 return coordinates;
287
288 }
289
290 }