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Java example source code file (VectorFormat.java)

This example Java source code file (VectorFormat.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

default_prefix, default_separator, default_suffix, fieldposition, locale, mathparseexception, numberformat, parseposition, space, string, stringbuffer, text, util, vectorformat

The VectorFormat.java Java example source code

/*
 * 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 java.text.FieldPosition;
import java.text.NumberFormat;
import java.text.ParsePosition;
import java.util.Locale;

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

/**
 * 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>
 * <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>
 * <p>Note: 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.</p>
 *
 * @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.</p>
     */
    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; } }

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