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/*
 * 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.linear;

import java.text.FieldPosition;
import java.text.NumberFormat;
import java.text.ParsePosition;
import java.util.ArrayList;
import java.util.List;
import java.util.Locale;

import org.apache.commons.math3.exception.MathParseException;
import org.apache.commons.math3.util.CompositeFormat;

/**
 * Formats a vector in components list format "{v0; v1; ...; vk-1}".
 * 

The prefix and suffix "{" and "}" and the separator "; " can be replaced by * any user-defined strings. The number format for components can be configured.

*

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.

* * @since 2.0 */ public class RealVectorFormat { /** The default prefix: "{". */ private static final String DEFAULT_PREFIX = "{"; /** The default suffix: "}". */ private static final String DEFAULT_SUFFIX = "}"; /** The default separator: ", ". */ private 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. *

The instance uses the default prefix, suffix and separator: * "{", "}", and "; " and the default number format for components.

*/ public RealVectorFormat() { 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. */ public RealVectorFormat(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 "; " */ public RealVectorFormat(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. */ public RealVectorFormat(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 real vectors formats are available. *

This is the same set as the {@link NumberFormat} set.

* @return available real 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; } /** * Returns the default real vector format for the current locale. * @return the default real vector format. */ public static RealVectorFormat getInstance() { return getInstance(Locale.getDefault()); } /** * Returns the default real vector format for the given locale. * @param locale the specific locale used by the format. * @return the real vector format specific to the given locale. */ public static RealVectorFormat getInstance(final Locale locale) { return new RealVectorFormat(CompositeFormat.getDefaultNumberFormat(locale)); } /** * This method calls {@link #format(RealVector,StringBuffer,FieldPosition)}. * * @param v RealVector object to format. * @return a formatted vector. */ public String format(RealVector v) { return format(v, new StringBuffer(), new FieldPosition(0)).toString(); } /** * Formats a {@link RealVector} 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 StringBuffer format(RealVector vector, StringBuffer toAppendTo, FieldPosition pos) { pos.setBeginIndex(0); pos.setEndIndex(0); // format prefix toAppendTo.append(prefix); // format components for (int i = 0; i < vector.getDimension(); ++i) { if (i > 0) { toAppendTo.append(separator); } CompositeFormat.formatDouble(vector.getEntry(i), format, toAppendTo, pos); } // format suffix toAppendTo.append(suffix); return toAppendTo; } /** * Parse a string to produce a {@link RealVector} object. * * @param source String to parse. * @return the parsed {@link RealVector} object. * @throws MathParseException if the beginning of the specified string * cannot be parsed. */ public ArrayRealVector parse(String source) { final ParsePosition parsePosition = new ParsePosition(0); final ArrayRealVector result = parse(source, parsePosition); if (parsePosition.getIndex() == 0) { throw new MathParseException(source, parsePosition.getErrorIndex(), ArrayRealVector.class); } return result; } /** * Parse a string to produce a {@link RealVector} object. * * @param source String to parse. * @param pos input/ouput parsing parameter. * @return the parsed {@link RealVector} object. */ public ArrayRealVector parse(String source, ParsePosition pos) { int initialIndex = pos.getIndex(); // parse prefix CompositeFormat.parseAndIgnoreWhitespace(source, pos); if (!CompositeFormat.parseFixedstring(source, trimmedPrefix, pos)) { return null; } // parse components List components = new ArrayList(); for (boolean loop = true; loop;){ if (!components.isEmpty()) { CompositeFormat.parseAndIgnoreWhitespace(source, pos); if (!CompositeFormat.parseFixedstring(source, trimmedSeparator, pos)) { loop = false; } } if (loop) { CompositeFormat.parseAndIgnoreWhitespace(source, pos); Number component = CompositeFormat.parseNumber(source, format, pos); if (component != null) { components.add(component); } else { // invalid component // set index back to initial, error index should already be set pos.setIndex(initialIndex); return null; } } } // parse suffix CompositeFormat.parseAndIgnoreWhitespace(source, pos); if (!CompositeFormat.parseFixedstring(source, trimmedSuffix, pos)) { return null; } // build vector double[] data = new double[components.size()]; for (int i = 0; i < data.length; ++i) { data[i] = components.get(i).doubleValue(); } return new ArrayRealVector(data, false); } }




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