    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    }