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.linear;
019
020 import java.text.FieldPosition;
021 import java.text.NumberFormat;
022 import java.text.ParsePosition;
023 import java.util.ArrayList;
024 import java.util.List;
025 import java.util.Locale;
026
027 import org.apache.commons.math3.exception.MathParseException;
028 import org.apache.commons.math3.util.CompositeFormat;
029
030 /**
031 * Formats a vector in components list format "{v0; v1; ...; vk-1}".
032 * <p>The prefix and suffix "{" and "}" and the separator "; " can be replaced by
033 * any user-defined strings. The number format for components can be configured.</p>
034 * <p>White space is ignored at parse time, even if it is in the prefix, suffix
035 * or separator specifications. So even if the default separator does include a space
036 * character that is used at format time, both input string "{1;1;1}" and
037 * " { 1 ; 1 ; 1 } " will be parsed without error and the same vector will be
038 * returned. In the second case, however, the parse position after parsing will be
039 * just after the closing curly brace, i.e. just before the trailing space.</p>
040 *
041 * @version $Id: RealVectorFormat.java 1416643 2012-12-03 19:37:14Z tn $
042 * @since 2.0
043 */
044 public class RealVectorFormat {
045
046 /** The default prefix: "{". */
047 private static final String DEFAULT_PREFIX = "{";
048 /** The default suffix: "}". */
049 private static final String DEFAULT_SUFFIX = "}";
050 /** The default separator: ", ". */
051 private static final String DEFAULT_SEPARATOR = "; ";
052 /** Prefix. */
053 private final String prefix;
054 /** Suffix. */
055 private final String suffix;
056 /** Separator. */
057 private final String separator;
058 /** Trimmed prefix. */
059 private final String trimmedPrefix;
060 /** Trimmed suffix. */
061 private final String trimmedSuffix;
062 /** Trimmed separator. */
063 private final String trimmedSeparator;
064 /** The format used for components. */
065 private final NumberFormat format;
066
067 /**
068 * Create an instance with default settings.
069 * <p>The instance uses the default prefix, suffix and separator:
070 * "{", "}", and "; " and the default number format for components.</p>
071 */
072 public RealVectorFormat() {
073 this(DEFAULT_PREFIX, DEFAULT_SUFFIX, DEFAULT_SEPARATOR,
074 CompositeFormat.getDefaultNumberFormat());
075 }
076
077 /**
078 * Create an instance with a custom number format for components.
079 * @param format the custom format for components.
080 */
081 public RealVectorFormat(final NumberFormat format) {
082 this(DEFAULT_PREFIX, DEFAULT_SUFFIX, DEFAULT_SEPARATOR, format);
083 }
084
085 /**
086 * Create an instance with custom prefix, suffix and separator.
087 * @param prefix prefix to use instead of the default "{"
088 * @param suffix suffix to use instead of the default "}"
089 * @param separator separator to use instead of the default "; "
090 */
091 public RealVectorFormat(final String prefix, final String suffix,
092 final String separator) {
093 this(prefix, suffix, separator,
094 CompositeFormat.getDefaultNumberFormat());
095 }
096
097 /**
098 * Create an instance with custom prefix, suffix, separator and format
099 * for components.
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 * @param format the custom format for components.
104 */
105 public RealVectorFormat(final String prefix, final String suffix,
106 final String separator, final NumberFormat format) {
107 this.prefix = prefix;
108 this.suffix = suffix;
109 this.separator = separator;
110 trimmedPrefix = prefix.trim();
111 trimmedSuffix = suffix.trim();
112 trimmedSeparator = separator.trim();
113 this.format = format;
114 }
115
116 /**
117 * Get the set of locales for which real vectors formats are available.
118 * <p>This is the same set as the {@link NumberFormat} set.</p>
119 * @return available real vector format locales.
120 */
121 public static Locale[] getAvailableLocales() {
122 return NumberFormat.getAvailableLocales();
123 }
124
125 /**
126 * Get the format prefix.
127 * @return format prefix.
128 */
129 public String getPrefix() {
130 return prefix;
131 }
132
133 /**
134 * Get the format suffix.
135 * @return format suffix.
136 */
137 public String getSuffix() {
138 return suffix;
139 }
140
141 /**
142 * Get the format separator between components.
143 * @return format separator.
144 */
145 public String getSeparator() {
146 return separator;
147 }
148
149 /**
150 * Get the components format.
151 * @return components format.
152 */
153 public NumberFormat getFormat() {
154 return format;
155 }
156
157 /**
158 * Returns the default real vector format for the current locale.
159 * @return the default real vector format.
160 */
161 public static RealVectorFormat getInstance() {
162 return getInstance(Locale.getDefault());
163 }
164
165 /**
166 * Returns the default real vector format for the given locale.
167 * @param locale the specific locale used by the format.
168 * @return the real vector format specific to the given locale.
169 */
170 public static RealVectorFormat getInstance(final Locale locale) {
171 return new RealVectorFormat(CompositeFormat.getDefaultNumberFormat(locale));
172 }
173
174 /**
175 * This method calls {@link #format(RealVector,StringBuffer,FieldPosition)}.
176 *
177 * @param v RealVector object to format.
178 * @return a formatted vector.
179 */
180 public String format(RealVector v) {
181 return format(v, new StringBuffer(), new FieldPosition(0)).toString();
182 }
183
184 /**
185 * Formats a {@link RealVector} object to produce a string.
186 * @param vector the object to format.
187 * @param toAppendTo where the text is to be appended
188 * @param pos On input: an alignment field, if desired. On output: the
189 * offsets of the alignment field
190 * @return the value passed in as toAppendTo.
191 */
192 public StringBuffer format(RealVector vector, StringBuffer toAppendTo,
193 FieldPosition pos) {
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 < vector.getDimension(); ++i) {
203 if (i > 0) {
204 toAppendTo.append(separator);
205 }
206 CompositeFormat.formatDouble(vector.getEntry(i), format, toAppendTo, pos);
207 }
208
209 // format suffix
210 toAppendTo.append(suffix);
211
212 return toAppendTo;
213 }
214
215 /**
216 * Parse a string to produce a {@link RealVector} object.
217 *
218 * @param source String to parse.
219 * @return the parsed {@link RealVector} object.
220 * @throws MathParseException if the beginning of the specified string
221 * cannot be parsed.
222 */
223 public ArrayRealVector parse(String source) {
224 final ParsePosition parsePosition = new ParsePosition(0);
225 final ArrayRealVector result = parse(source, parsePosition);
226 if (parsePosition.getIndex() == 0) {
227 throw new MathParseException(source,
228 parsePosition.getErrorIndex(),
229 ArrayRealVector.class);
230 }
231 return result;
232 }
233
234 /**
235 * Parse a string to produce a {@link RealVector} object.
236 *
237 * @param source String to parse.
238 * @param pos input/ouput parsing parameter.
239 * @return the parsed {@link RealVector} object.
240 */
241 public ArrayRealVector parse(String source, ParsePosition pos) {
242 int initialIndex = pos.getIndex();
243
244 // parse prefix
245 CompositeFormat.parseAndIgnoreWhitespace(source, pos);
246 if (!CompositeFormat.parseFixedstring(source, trimmedPrefix, pos)) {
247 return null;
248 }
249
250 // parse components
251 List<Number> components = new ArrayList<Number>();
252 for (boolean loop = true; loop;){
253
254 if (!components.isEmpty()) {
255 CompositeFormat.parseAndIgnoreWhitespace(source, pos);
256 if (!CompositeFormat.parseFixedstring(source, trimmedSeparator, pos)) {
257 loop = false;
258 }
259 }
260
261 if (loop) {
262 CompositeFormat.parseAndIgnoreWhitespace(source, pos);
263 Number component = CompositeFormat.parseNumber(source, format, pos);
264 if (component != null) {
265 components.add(component);
266 } else {
267 // invalid component
268 // set index back to initial, error index should already be set
269 pos.setIndex(initialIndex);
270 return null;
271 }
272 }
273
274 }
275
276 // parse suffix
277 CompositeFormat.parseAndIgnoreWhitespace(source, pos);
278 if (!CompositeFormat.parseFixedstring(source, trimmedSuffix, pos)) {
279 return null;
280 }
281
282 // build vector
283 double[] data = new double[components.size()];
284 for (int i = 0; i < data.length; ++i) {
285 data[i] = components.get(i).doubleValue();
286 }
287 return new ArrayRealVector(data, false);
288 }
289 }