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Diffstat (limited to 'src/main/java/org/apache/commons/math3/geometry/VectorFormat.java')
-rw-r--r-- | src/main/java/org/apache/commons/math3/geometry/VectorFormat.java | 307 |
1 files changed, 307 insertions, 0 deletions
diff --git a/src/main/java/org/apache/commons/math3/geometry/VectorFormat.java b/src/main/java/org/apache/commons/math3/geometry/VectorFormat.java new file mode 100644 index 0000000..7c6d0c5 --- /dev/null +++ b/src/main/java/org/apache/commons/math3/geometry/VectorFormat.java @@ -0,0 +1,307 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.commons.math3.geometry; + +import org.apache.commons.math3.exception.MathParseException; +import org.apache.commons.math3.util.CompositeFormat; + +import java.text.FieldPosition; +import java.text.NumberFormat; +import java.text.ParsePosition; +import java.util.Locale; + +/** + * Formats a vector in components list format "{x; y; ...}". + * + * <p>The prefix and suffix "{" and "}" and the separator "; " can be replaced by any user-defined + * strings. The number format for components can be configured. + * + * <p>White space is ignored at parse time, even if it is in the prefix, suffix or separator + * specifications. So even if the default separator does include a space character that is used at + * format time, both input string "{1;1;1}" and " { 1 ; 1 ; 1 } " will be parsed without error and + * the same vector will be returned. In the second case, however, the parse position after parsing + * will be just after the closing curly brace, i.e. just before the trailing space. + * + * <p><b>Note:</b> using "," as a separator may interfere with the grouping separator of the default + * {@link NumberFormat} for the current locale. Thus it is advised to use a {@link NumberFormat} + * instance with disabled grouping in such a case. + * + * @param <S> Type of the space. + * @since 3.0 + */ +public abstract class VectorFormat<S extends Space> { + + /** The default prefix: "{". */ + public static final String DEFAULT_PREFIX = "{"; + + /** The default suffix: "}". */ + public static final String DEFAULT_SUFFIX = "}"; + + /** The default separator: ", ". */ + public static final String DEFAULT_SEPARATOR = "; "; + + /** Prefix. */ + private final String prefix; + + /** Suffix. */ + private final String suffix; + + /** Separator. */ + private final String separator; + + /** Trimmed prefix. */ + private final String trimmedPrefix; + + /** Trimmed suffix. */ + private final String trimmedSuffix; + + /** Trimmed separator. */ + private final String trimmedSeparator; + + /** The format used for components. */ + private final NumberFormat format; + + /** + * Create an instance with default settings. + * + * <p>The instance uses the default prefix, suffix and separator: "{", "}", and "; " and the + * default number format for components. + */ + protected VectorFormat() { + this( + DEFAULT_PREFIX, + DEFAULT_SUFFIX, + DEFAULT_SEPARATOR, + CompositeFormat.getDefaultNumberFormat()); + } + + /** + * Create an instance with a custom number format for components. + * + * @param format the custom format for components. + */ + protected VectorFormat(final NumberFormat format) { + this(DEFAULT_PREFIX, DEFAULT_SUFFIX, DEFAULT_SEPARATOR, format); + } + + /** + * Create an instance with custom prefix, suffix and separator. + * + * @param prefix prefix to use instead of the default "{" + * @param suffix suffix to use instead of the default "}" + * @param separator separator to use instead of the default "; " + */ + protected VectorFormat(final String prefix, final String suffix, final String separator) { + this(prefix, suffix, separator, CompositeFormat.getDefaultNumberFormat()); + } + + /** + * Create an instance with custom prefix, suffix, separator and format for components. + * + * @param prefix prefix to use instead of the default "{" + * @param suffix suffix to use instead of the default "}" + * @param separator separator to use instead of the default "; " + * @param format the custom format for components. + */ + protected VectorFormat( + final String prefix, + final String suffix, + final String separator, + final NumberFormat format) { + this.prefix = prefix; + this.suffix = suffix; + this.separator = separator; + trimmedPrefix = prefix.trim(); + trimmedSuffix = suffix.trim(); + trimmedSeparator = separator.trim(); + this.format = format; + } + + /** + * Get the set of locales for which point/vector formats are available. + * + * <p>This is the same set as the {@link NumberFormat} set. + * + * @return available point/vector format locales. + */ + public static Locale[] getAvailableLocales() { + return NumberFormat.getAvailableLocales(); + } + + /** + * Get the format prefix. + * + * @return format prefix. + */ + public String getPrefix() { + return prefix; + } + + /** + * Get the format suffix. + * + * @return format suffix. + */ + public String getSuffix() { + return suffix; + } + + /** + * Get the format separator between components. + * + * @return format separator. + */ + public String getSeparator() { + return separator; + } + + /** + * Get the components format. + * + * @return components format. + */ + public NumberFormat getFormat() { + return format; + } + + /** + * Formats a {@link Vector} object to produce a string. + * + * @param vector the object to format. + * @return a formatted string. + */ + public String format(Vector<S> vector) { + return format(vector, new StringBuffer(), new FieldPosition(0)).toString(); + } + + /** + * Formats a {@link Vector} object to produce a string. + * + * @param vector the object to format. + * @param toAppendTo where the text is to be appended + * @param pos On input: an alignment field, if desired. On output: the offsets of the alignment + * field + * @return the value passed in as toAppendTo. + */ + public abstract StringBuffer format( + Vector<S> vector, StringBuffer toAppendTo, FieldPosition pos); + + /** + * Formats the coordinates of a {@link Vector} to produce a string. + * + * @param toAppendTo where the text is to be appended + * @param pos On input: an alignment field, if desired. On output: the offsets of the alignment + * field + * @param coordinates coordinates of the object to format. + * @return the value passed in as toAppendTo. + */ + protected StringBuffer format( + StringBuffer toAppendTo, FieldPosition pos, double... coordinates) { + + pos.setBeginIndex(0); + pos.setEndIndex(0); + + // format prefix + toAppendTo.append(prefix); + + // format components + for (int i = 0; i < coordinates.length; ++i) { + if (i > 0) { + toAppendTo.append(separator); + } + CompositeFormat.formatDouble(coordinates[i], format, toAppendTo, pos); + } + + // format suffix + toAppendTo.append(suffix); + + return toAppendTo; + } + + /** + * Parses a string to produce a {@link Vector} object. + * + * @param source the string to parse + * @return the parsed {@link Vector} object. + * @throws MathParseException if the beginning of the specified string cannot be parsed. + */ + public abstract Vector<S> parse(String source) throws MathParseException; + + /** + * Parses a string to produce a {@link Vector} object. + * + * @param source the string to parse + * @param pos input/output parsing parameter. + * @return the parsed {@link Vector} object. + */ + public abstract Vector<S> parse(String source, ParsePosition pos); + + /** + * Parses a string to produce an array of coordinates. + * + * @param dimension dimension of the space + * @param source the string to parse + * @param pos input/output parsing parameter. + * @return coordinates array. + */ + protected double[] parseCoordinates(int dimension, String source, ParsePosition pos) { + + int initialIndex = pos.getIndex(); + double[] coordinates = new double[dimension]; + + // parse prefix + CompositeFormat.parseAndIgnoreWhitespace(source, pos); + if (!CompositeFormat.parseFixedstring(source, trimmedPrefix, pos)) { + return null; + } + + for (int i = 0; i < dimension; ++i) { + + // skip whitespace + CompositeFormat.parseAndIgnoreWhitespace(source, pos); + + // parse separator + if (i > 0 && !CompositeFormat.parseFixedstring(source, trimmedSeparator, pos)) { + return null; + } + + // skip whitespace + CompositeFormat.parseAndIgnoreWhitespace(source, pos); + + // parse coordinate + Number c = CompositeFormat.parseNumber(source, format, pos); + if (c == null) { + // invalid coordinate + // set index back to initial, error index should already be set + pos.setIndex(initialIndex); + return null; + } + + // store coordinate + coordinates[i] = c.doubleValue(); + } + + // parse suffix + CompositeFormat.parseAndIgnoreWhitespace(source, pos); + if (!CompositeFormat.parseFixedstring(source, trimmedSuffix, pos)) { + return null; + } + + return coordinates; + } +} |