choiceformat.java

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/*
 * @(#)ChoiceFormat.java	1.11 97/02/06
 *
 * (C) Copyright Taligent, Inc. 1996-1997 - All Rights Reserved
 * (C) Copyright IBM Corp. 1996-1997 - All Rights Reserved
 *
 * Portions copyright (c) 1996-1997 Sun Microsystems, Inc. All Rights Reserved.
 *
 *   The original version of this source code and documentation is copyrighted
 * and owned by Taligent, Inc., a wholly-owned subsidiary of IBM. These
 * materials are provided under terms of a License Agreement between Taligent
 * and Sun. This technology is protected by multiple US and International
 * patents. This notice and attribution to Taligent may not be removed.
 *   Taligent is a registered trademark of Taligent, Inc.
 *
 * Permission to use, copy, modify, and distribute this software
 * and its documentation for NON-COMMERCIAL purposes and without
 * fee is hereby granted provided that this copyright notice
 * appears in all copies. Please refer to the file "copyright.html"
 * for further important copyright and licensing information.
 *
 * SUN MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF
 * THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
 * TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE, OR NON-INFRINGEMENT. SUN SHALL NOT BE LIABLE FOR
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
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 */

package java.text;
import java.text.Utility;

/**
 * A <code>ChoiceFormat</code> allows you to attach a format to a range of numbers.
 * It is generally used in a <code>MessageFormat</code> for handling plurals.
 * The choice is specified with an ascending list of doubles, where each item
 * specifies a half-open interval up to the next item:
 * <blockquote>
 * <pre>
 * X matches j if and only if limit[j] <= X < limit[j+1]
 * </pre>
 * </blockquote>
 * If there is no match, then either the first or last index is used, depending
 * on whether the number (X) is too low or too high.
 *
 * <p>
 * <strong>Note:</strong>
 * <code>ChoiceFormat</code> differs from the other <code>Format</code>
 * classes in that you create a <code>ChoiceFormat</code> object with a
 * constructor (not with a <code>getInstance</code> style factory
 * method). The factory methods aren't necessary because <code>ChoiceFormat</code>
 * doesn't require any complex setup for a given locale. In fact,
 * <code>ChoiceFormat</code> doesn't implement any locale specific behavior.
 *
 * <p>
 * When creating a <code>ChoiceFormat</code>, you must specify an array of formats
 * and an array of limits. The length of these arrays must be the same.
 * For example,
 * <ul>
 * <li>
 *     <em>limits</em> = {1,2,3,4,5,6,7}<br>
 *     <em>formats</em> = {"Sun","Mon","Tue","Wed","Thur","Fri","Sat"}
 * <lie>
 *     <em>limits</em> = {0, 1, ChoiceFormat.nextDouble(1)}<br>
 *     <em>formats</em> = {"no files", "one file", "many files"}<br>
 *     (<code>nextDouble</code> can be used to get the next higher double, to
 *     make the half-open interval.)
 * </ul>
 *
 * <p>
 * Here is a simple example that shows formatting and parsing:
 * <blockquote>
 * <pre>
 * double[] limits = {1,2,3,4,5,6,7};
 * String[] monthNames = {"Sun","Mon","Tue","Wed","Thur","Fri","Sat"};
 * ChoiceFormat form = new ChoiceFormat(limits, monthNames);
 * ParsePosition status = new ParsePosition(0);
 * for (double i = 0.0; i <= 8.0; ++i) {
 *     status.setIndex(0);
 *     System.out.println(i + " -> " + form.format(i) + " -> "
 *                              + form.parse(form.format(i),status));
 * }
 * </pre>
 * </blockquote>
 * Here is a more complex example, with a pattern format:
 * <blockquote>
 * <pre>
 * double[] filelimits = {0,1,2};
 * String[] filepart = {"are no files","is one file","are {2} files"};
 * ChoiceFormat fileform = new ChoiceFormat(filelimits, filepart);
 * Format[] testFormats = {fileform, null, NumberFormat.getInstance()};
 * MessageFormat pattform = new MessageFormat("There {0} on {1}");
 * pattform.setFormats(testFormats);
 * Object[] testArgs = {null, "ADisk", null};
 * for (int i = 0; i < 4; ++i) {
 *     testArgs[0] = new Integer(i);
 *     testArgs[2] = testArgs[0];
 *     System.out.println(pattform.format(testArgs));
 * }
 * </pre>
 * </blockquote>
 * @see          DecimalFormat
 * @see          MessageFormat
 * @version      1.11 02/06/97
 * @author       Mark Davis
 */
public class ChoiceFormat extends NumberFormat {
    /**
     * Sets the pattern.
     * @param newPattern See the class description.
     */
    public void applyPattern(String newPattern) {
            StringBuffer[] segments = new StringBuffer[2];
            for (int i = 0; i < segments.length; ++i) {
                segments[i] = new StringBuffer();       // later, use single
            }
            double[] newChoiceLimits = new double[30];	// current limit
            String[] newChoiceFormats = new String[30];   // later, use Vectors
            int count = 0;
            int part = 0;
            double startValue = 0;
            double oldStartValue = Double.NaN;
            boolean inQuote = false;
            for (int i = 0; i < newPattern.length(); ++i) {
                char ch = newPattern.charAt(i);
                if (ch == '<' || ch == '#' || ch == '\u2264') {
                    if (segments[0].equals("")) {
                        throw new IllegalArgumentException();
                    }
                    try {
                        startValue = Double.valueOf(segments[0].toString()).doubleValue();
                    } catch (Exception e) {
                        throw new IllegalArgumentException();
                    }
                    if (ch == '<') {
                        startValue = nextDouble(startValue);
                    }
                    if (startValue <= oldStartValue) {
                        throw new IllegalArgumentException();
                    }
                    segments[0].setLength(0);
                    part = 1;
                } else if (ch == '|') {
				//System.out.println("***" + startValue + "," + segments[1].toString());
                    newChoiceLimits[count] = startValue;
                    newChoiceFormats[count] = segments[1].toString();
                    ++count;
                    oldStartValue = startValue;
                    segments[1].setLength(0);
                    part = 0;
                } else {
                    segments[part].append(ch);
                }
            }
            // clean up last one
            if (part == 1) {
                newChoiceLimits[count] = startValue;
     		newChoiceFormats[count] = segments[1].toString();
                //System.out.println("***" + newChoiceLimits[count] + "," + newChoiceFormats[count]);
                ++count;
            }
            // compact arrays
            //System.out.println("***" + count);
            choiceLimits = new double[count];
            System.arraycopy(newChoiceLimits, 0, choiceLimits, 0, count);
            choiceFormats = new String[count];
            System.arraycopy(newChoiceFormats, 0, choiceFormats, 0, count);
            //for (int i = 0; i < choiceLimits.length; ++i) {
            //System.out.println("&&<" + choiceLimits[i]);
            //System.out.println("&&>" + choiceFormats[i]);
            //}
    }
    /**
     * Gets the pattern.
     */

    public String toPattern() {
        StringBuffer result = new StringBuffer();
        //System.out.println("&&&" + choiceLimits.length);
        for (int i = 0; i < choiceLimits.length; ++i) {
            //System.out.println("&&<" + choiceLimits[i] + ";"
            //	+ Long.toString(Double.doubleToLongBits(choiceLimits[i]),16)
            //	+ ";" + choiceFormats[i]);
            if (i != 0) {
                result.append('|');
            }
            // choose based upon which has less precision
            // approximate that by choosing the closest one to an integer.
            // could do better, but it's not worth it.
            double less = previousDouble(choiceLimits[i]);
            double tryLessOrEqual = Math.abs(Math.IEEEremainder(choiceLimits[i], 1.0d));
            double tryLess = Math.abs(Math.IEEEremainder(less, 1.0d));
            if (tryLessOrEqual < tryLess) {
                result.append(""+choiceLimits[i]);
                result.append('#');
            } else {
                result.append(""+less);
                result.append('<');
            }
            result.append(choiceFormats[i].toString());
        }
        return result.toString();
    }

    /**
     * Constructs with limits and corresponding formats based on the pattern.
     */
    public ChoiceFormat(String newPattern)  {
        applyPattern(newPattern);
    }
    /**
     * Constructs with the limits and the corresponding formats.
     * @see #setChoices
     */
    public ChoiceFormat(double[] limits, String[] formats) {
        setChoices(limits, formats);
    }
    /**
     * Set the choices to be used in formatting.
     * @param limits contains the top value that you want
     * parsed with that format,and should be in ascending sorted order. When
     * formatting X, the choice will be the i, where limit[i] <= X < limit[i+1].