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.math.linear;
019
020 import java.text.FieldPosition;
021 import java.text.NumberFormat;
022 import java.text.ParseException;
023 import java.text.ParsePosition;
024 import java.util.ArrayList;
025 import java.util.List;
026 import java.util.Locale;
027
028 import org.apache.commons.math.MathRuntimeException;
029 import org.apache.commons.math.exception.util.LocalizedFormats;
030 import org.apache.commons.math.util.CompositeFormat;
031
032 /**
033 * Formats a vector in components list format "{v0; v1; ...; vk-1}".
034 * <p>The prefix and suffix "{" and "}" and the separator "; " can be replaced by
035 * any user-defined strings. The number format for components can be configured.</p>
036 * <p>White space is ignored at parse time, even if it is in the prefix, suffix
037 * or separator specifications. So even if the default separator does include a space
038 * character that is used at format time, both input string "{1;1;1}" and
039 * " { 1 ; 1 ; 1 } " will be parsed without error and the same vector will be
040 * returned. In the second case, however, the parse position after parsing will be
041 * just after the closing curly brace, i.e. just before the trailing space.</p>
042 *
043 * @version $Revision: 1003886 $ $Date: 2010-10-02 23:04:44 +0200 (sam. 02 oct. 2010) $
044 * @since 2.0
045 */
046 public class RealVectorFormat extends CompositeFormat {
047
048 /** Serializable version identifier */
049 private static final long serialVersionUID = -708767813036157690L;
050
051 /** The default prefix: "{". */
052 private static final String DEFAULT_PREFIX = "{";
053
054 /** The default suffix: "}". */
055 private static final String DEFAULT_SUFFIX = "}";
056
057 /** The default separator: ", ". */
058 private static final String DEFAULT_SEPARATOR = "; ";
059
060 /** Prefix. */
061 private final String prefix;
062
063 /** Suffix. */
064 private final String suffix;
065
066 /** Separator. */
067 private final String separator;
068
069 /** Trimmed prefix. */
070 private final String trimmedPrefix;
071
072 /** Trimmed suffix. */
073 private final String trimmedSuffix;
074
075 /** Trimmed separator. */
076 private final String trimmedSeparator;
077
078 /** The format used for components. */
079 private final NumberFormat format;
080
081 /**
082 * Create an instance with default settings.
083 * <p>The instance uses the default prefix, suffix and separator:
084 * "{", "}", and "; " and the default number format for components.</p>
085 */
086 public RealVectorFormat() {
087 this(DEFAULT_PREFIX, DEFAULT_SUFFIX, DEFAULT_SEPARATOR, getDefaultNumberFormat());
088 }
089
090 /**
091 * Create an instance with a custom number format for components.
092 * @param format the custom format for components.
093 */
094 public RealVectorFormat(final NumberFormat format) {
095 this(DEFAULT_PREFIX, DEFAULT_SUFFIX, DEFAULT_SEPARATOR, format);
096 }
097
098 /**
099 * Create an instance with custom prefix, suffix and separator.
100 * @param prefix prefix to use instead of the default "{"
101 * @param suffix suffix to use instead of the default "}"
102 * @param separator separator to use instead of the default "; "
103 */
104 public RealVectorFormat(final String prefix, final String suffix,
105 final String separator) {
106 this(prefix, suffix, separator, getDefaultNumberFormat());
107 }
108
109 /**
110 * Create an instance with custom prefix, suffix, separator and format
111 * for components.
112 * @param prefix prefix to use instead of the default "{"
113 * @param suffix suffix to use instead of the default "}"
114 * @param separator separator to use instead of the default "; "
115 * @param format the custom format for components.
116 */
117 public RealVectorFormat(final String prefix, final String suffix,
118 final String separator, final NumberFormat format) {
119 this.prefix = prefix;
120 this.suffix = suffix;
121 this.separator = separator;
122 trimmedPrefix = prefix.trim();
123 trimmedSuffix = suffix.trim();
124 trimmedSeparator = separator.trim();
125 this.format = format;
126 }
127
128 /**
129 * Get the set of locales for which real vectors formats are available.
130 * <p>This is the same set as the {@link NumberFormat} set.</p>
131 * @return available real vector format locales.
132 */
133 public static Locale[] getAvailableLocales() {
134 return NumberFormat.getAvailableLocales();
135 }
136
137 /**
138 * Get the format prefix.
139 * @return format prefix.
140 */
141 public String getPrefix() {
142 return prefix;
143 }
144
145 /**
146 * Get the format suffix.
147 * @return format suffix.
148 */
149 public String getSuffix() {
150 return suffix;
151 }
152
153 /**
154 * Get the format separator between components.
155 * @return format separator.
156 */
157 public String getSeparator() {
158 return separator;
159 }
160
161 /**
162 * Get the components format.
163 * @return components format.
164 */
165 public NumberFormat getFormat() {
166 return format;
167 }
168
169 /**
170 * Returns the default real vector format for the current locale.
171 * @return the default real vector format.
172 */
173 public static RealVectorFormat getInstance() {
174 return getInstance(Locale.getDefault());
175 }
176
177 /**
178 * Returns the default real vector format for the given locale.
179 * @param locale the specific locale used by the format.
180 * @return the real vector format specific to the given locale.
181 */
182 public static RealVectorFormat getInstance(final Locale locale) {
183 return new RealVectorFormat(getDefaultNumberFormat(locale));
184 }
185
186 /**
187 * This static method calls {@link #format(Object)} on a default instance of
188 * RealVectorFormat.
189 *
190 * @param v RealVector object to format
191 * @return A formatted vector
192 */
193 public static String formatRealVector(RealVector v) {
194 return getInstance().format(v);
195 }
196
197 /**
198 * Formats a {@link RealVector} object to produce a string.
199 * @param vector the object to format.
200 * @param toAppendTo where the text is to be appended
201 * @param pos On input: an alignment field, if desired. On output: the
202 * offsets of the alignment field
203 * @return the value passed in as toAppendTo.
204 */
205 public StringBuffer format(RealVector vector, StringBuffer toAppendTo,
206 FieldPosition pos) {
207
208 pos.setBeginIndex(0);
209 pos.setEndIndex(0);
210
211 // format prefix
212 toAppendTo.append(prefix);
213
214 // format components
215 for (int i = 0; i < vector.getDimension(); ++i) {
216 if (i > 0) {
217 toAppendTo.append(separator);
218 }
219 formatDouble(vector.getEntry(i), format, toAppendTo, pos);
220 }
221
222 // format suffix
223 toAppendTo.append(suffix);
224
225 return toAppendTo;
226
227 }
228
229 /**
230 * Formats a object to produce a string.
231 * <p><code>obj</code> must be a {@link RealVector} object. Any other type of
232 * object will result in an {@link IllegalArgumentException} being thrown.</p>
233 * @param obj the object to format.
234 * @param toAppendTo where the text is to be appended
235 * @param pos On input: an alignment field, if desired. On output: the
236 * offsets of the alignment field
237 * @return the value passed in as toAppendTo.
238 * @see java.text.Format#format(java.lang.Object, java.lang.StringBuffer, java.text.FieldPosition)
239 * @throws IllegalArgumentException is <code>obj</code> is not a valid type.
240 */
241 @Override
242 public StringBuffer format(Object obj, StringBuffer toAppendTo,
243 FieldPosition pos) {
244
245 if (obj instanceof RealVector) {
246 return format( (RealVector)obj, toAppendTo, pos);
247 }
248
249 throw MathRuntimeException.createIllegalArgumentException(
250 LocalizedFormats.CANNOT_FORMAT_INSTANCE_AS_REAL_VECTOR,
251 obj.getClass().getName());
252
253 }
254
255 /**
256 * Parses a string to produce a {@link RealVector} object.
257 * @param source the string to parse
258 * @return the parsed {@link RealVector} object.
259 * @exception ParseException if the beginning of the specified string
260 * cannot be parsed.
261 */
262 public ArrayRealVector parse(String source) throws ParseException {
263 ParsePosition parsePosition = new ParsePosition(0);
264 ArrayRealVector result = parse(source, parsePosition);
265 if (parsePosition.getIndex() == 0) {
266 throw MathRuntimeException.createParseException(
267 parsePosition.getErrorIndex(),
268 LocalizedFormats.UNPARSEABLE_REAL_VECTOR, source);
269 }
270 return result;
271 }
272
273 /**
274 * Parses a string to produce a {@link RealVector} object.
275 * @param source the string to parse
276 * @param pos input/ouput parsing parameter.
277 * @return the parsed {@link RealVector} object.
278 */
279 public ArrayRealVector parse(String source, ParsePosition pos) {
280 int initialIndex = pos.getIndex();
281
282 // parse prefix
283 parseAndIgnoreWhitespace(source, pos);
284 if (!parseFixedstring(source, trimmedPrefix, pos)) {
285 return null;
286 }
287
288 // parse components
289 List<Number> components = new ArrayList<Number>();
290 for (boolean loop = true; loop;){
291
292 if (!components.isEmpty()) {
293 parseAndIgnoreWhitespace(source, pos);
294 if (!parseFixedstring(source, trimmedSeparator, pos)) {
295 loop = false;
296 }
297 }
298
299 if (loop) {
300 parseAndIgnoreWhitespace(source, pos);
301 Number component = parseNumber(source, format, pos);
302 if (component != null) {
303 components.add(component);
304 } else {
305 // invalid component
306 // set index back to initial, error index should already be set
307 pos.setIndex(initialIndex);
308 return null;
309 }
310 }
311
312 }
313
314 // parse suffix
315 parseAndIgnoreWhitespace(source, pos);
316 if (!parseFixedstring(source, trimmedSuffix, pos)) {
317 return null;
318 }
319
320 // build vector
321 double[] data = new double[components.size()];
322 for (int i = 0; i < data.length; ++i) {
323 data[i] = components.get(i).doubleValue();
324 }
325 return new ArrayRealVector(data, false);
326
327 }
328
329 /**
330 * Parses a string to produce a object.
331 * @param source the string to parse
332 * @param pos input/ouput parsing parameter.
333 * @return the parsed object.
334 * @see java.text.Format#parseObject(java.lang.String, java.text.ParsePosition)
335 */
336 @Override
337 public Object parseObject(String source, ParsePosition pos) {
338 return parse(source, pos);
339 }
340
341 }