/*

 * Copyright (c) 1996, 2017, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

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 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

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/*

 * (C) Copyright Taligent, Inc. 1996, 1997 - All Rights Reserved

 * (C) Copyright IBM Corp. 1996 - 1998 - 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.

 *

 */

package java.text;

import java.io.InvalidObjectException;

import java.io.IOException;

import java.io.ObjectInputStream;

import java.text.DecimalFormat;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Date;

import java.util.List;

import java.util.Locale;

/**

 * <code>MessageFormat</code> provides a means to produce concatenated

 * messages in a language-neutral way. Use this to construct messages

 * displayed for end users.

 *

 * <p>

 * <code>MessageFormat</code> takes a set of objects, formats them, then

 * inserts the formatted strings into the pattern at the appropriate places.

 *

 * <p>

 * <strong>Note:</strong>

 * <code>MessageFormat</code> differs from the other <code>Format</code>

 * classes in that you create a <code>MessageFormat</code> object with one

 * of its constructors (not with a <code>getInstance</code> style factory

 * method). The factory methods aren't necessary because <code>MessageFormat</code>

 * itself doesn't implement locale specific behavior. Any locale specific

 * behavior is defined by the pattern that you provide as well as the

 * subformats used for inserted arguments.

 *

 * <h3><a id="patterns">Patterns and Their Interpretation</a></h3>

 *

 * <code>MessageFormat</code> uses patterns of the following form:

 * <blockquote><pre>

 * <i>MessageFormatPattern:</i>

 *         <i>String</i>

 *         <i>MessageFormatPattern</i> <i>FormatElement</i> <i>String</i>

 *

 * <i>FormatElement:</i>

 *         { <i>ArgumentIndex</i> }

 *         { <i>ArgumentIndex</i> , <i>FormatType</i> }

 *         { <i>ArgumentIndex</i> , <i>FormatType</i> , <i>FormatStyle</i> }

 *

 * <i>FormatType: one of </i>

 *         number date time choice

 *

 * <i>FormatStyle:</i>

 *         short

 *         medium

 *         long

 *         full

 *         integer

 *         currency

 *         percent

 *         <i>SubformatPattern</i>

 * </pre></blockquote>

 *

 * <p>Within a <i>String</i>, a pair of single quotes can be used to

 * quote any arbitrary characters except single quotes. For example,

 * pattern string <code>"'{0}'"</code> represents string

 * <code>"{0}"</code>, not a <i>FormatElement</i>. A single quote itself

 * must be represented by doubled single quotes {@code ''} throughout a

 * <i>String</i>.  For example, pattern string <code>"'{''}'"</code> is

 * interpreted as a sequence of <code>'{</code> (start of quoting and a

 * left curly brace), <code>''</code> (a single quote), and

 * <code>}'</code> (a right curly brace and end of quoting),

 * <em>not</em> <code>'{'</code> and <code>'}'</code> (quoted left and

 * right curly braces): representing string <code>"{'}"</code>,

 * <em>not</em> <code>"{}"</code>.

 *

 * <p>A <i>SubformatPattern</i> is interpreted by its corresponding

 * subformat, and subformat-dependent pattern rules apply. For example,

 * pattern string <code>"{1,number,<u>$'#',##</u>}"</code>

 * (<i>SubformatPattern</i> with underline) will produce a number format

 * with the pound-sign quoted, with a result such as: {@code

 * "$#31,45"}. Refer to each {@code Format} subclass documentation for

 * details.

 *

 * <p>Any unmatched quote is treated as closed at the end of the given

 * pattern. For example, pattern string {@code "'{0}"} is treated as

 * pattern {@code "'{0}'"}.

 *

 * <p>Any curly braces within an unquoted pattern must be balanced. For

 * example, <code>"ab {0} de"</code> and <code>"ab '}' de"</code> are

 * valid patterns, but <code>"ab {0'}' de"</code>, <code>"ab } de"</code>

 * and <code>"''{''"</code> are not.

 *

 * <dl><dt><b>Warning:</b><dd>The rules for using quotes within message

 * format patterns unfortunately have shown to be somewhat confusing.

 * In particular, it isn't always obvious to localizers whether single

 * quotes need to be doubled or not. Make sure to inform localizers about

 * the rules, and tell them (for example, by using comments in resource

 * bundle source files) which strings will be processed by {@code MessageFormat}.

 * Note that localizers may need to use single quotes in translated

 * strings where the original version doesn't have them.

 * </dl>

 * <p>

 * The <i>ArgumentIndex</i> value is a non-negative integer written

 * using the digits {@code '0'} through {@code '9'}, and represents an index into the

 * {@code arguments} array passed to the {@code format} methods

 * or the result array returned by the {@code parse} methods.

 * <p>

 * The <i>FormatType</i> and <i>FormatStyle</i> values are used to create

 * a {@code Format} instance for the format element. The following

 * table shows how the values map to {@code Format} instances. Combinations not

 * shown in the table are illegal. A <i>SubformatPattern</i> must

 * be a valid pattern string for the {@code Format} subclass used.

 *

 * <table class="plain">

 * <caption style="display:none">Shows how FormatType and FormatStyle values map to Format instances</caption>

 * <thead>

 *    <tr>

 *       <th scope="col" class="TableHeadingColor">FormatType

 *       <th scope="col" class="TableHeadingColor">FormatStyle

 *       <th scope="col" class="TableHeadingColor">Subformat Created

 * </thead>

 * <tbody>

 *    <tr>

 *       <th scope="row" style="text-weight: normal"><i>(none)</i>

 *       <th scope="row" style="text-weight: normal"><i>(none)</i>

 *       <td>{@code null}

 *    <tr>

 *       <th scope="row" style="text-weight: normal" rowspan=5>{@code number}

 *       <th scope="row" style="text-weight: normal"><i>(none)</i>

 *       <td>{@link NumberFormat#getInstance(Locale) NumberFormat.getInstance}{@code (getLocale())}

 *    <tr>

 *       <th scope="row" style="text-weight: normal">{@code integer}

 *       <td>{@link NumberFormat#getIntegerInstance(Locale) NumberFormat.getIntegerInstance}{@code (getLocale())}

 *    <tr>

 *       <th scope="row" style="text-weight: normal">{@code currency}

 *       <td>{@link NumberFormat#getCurrencyInstance(Locale) NumberFormat.getCurrencyInstance}{@code (getLocale())}

 *    <tr>

 *       <th scope="row" style="text-weight: normal">{@code percent}

 *       <td>{@link NumberFormat#getPercentInstance(Locale) NumberFormat.getPercentInstance}{@code (getLocale())}

 *    <tr>

 *       <th scope="row" style="text-weight: normal"><i>SubformatPattern</i>

 *       <td>{@code new} {@link DecimalFormat#DecimalFormat(String,DecimalFormatSymbols) DecimalFormat}{@code (subformatPattern,} {@link DecimalFormatSymbols#getInstance(Locale) DecimalFormatSymbols.getInstance}{@code (getLocale()))}

 *    <tr>

 *       <th scope="row" style="text-weight: normal" rowspan=6>{@code date}

 *       <th scope="row" style="text-weight: normal"><i>(none)</i>

 *       <td>{@link DateFormat#getDateInstance(int,Locale) DateFormat.getDateInstance}{@code (}{@link DateFormat#DEFAULT}{@code , getLocale())}

 *    <tr>

 *       <th scope="row" style="text-weight: normal">{@code short}

 *       <td>{@link DateFormat#getDateInstance(int,Locale) DateFormat.getDateInstance}{@code (}{@link DateFormat#SHORT}{@code , getLocale())}

 *    <tr>

 *       <th scope="row" style="text-weight: normal">{@code medium}

 *       <td>{@link DateFormat#getDateInstance(int,Locale) DateFormat.getDateInstance}{@code (}{@link DateFormat#DEFAULT}{@code , getLocale())}

 *    <tr>

 *       <th scope="row" style="text-weight: normal">{@code long}

 *       <td>{@link DateFormat#getDateInstance(int,Locale) DateFormat.getDateInstance}{@code (}{@link DateFormat#LONG}{@code , getLocale())}

 *    <tr>

 *       <th scope="row" style="text-weight: normal">{@code full}

 *       <td>{@link DateFormat#getDateInstance(int,Locale) DateFormat.getDateInstance}{@code (}{@link DateFormat#FULL}{@code , getLocale())}

 *    <tr>

 *       <th scope="row" style="text-weight: normal"><i>SubformatPattern</i>

 *       <td>{@code new} {@link SimpleDateFormat#SimpleDateFormat(String,Locale) SimpleDateFormat}{@code (subformatPattern, getLocale())}

 *    <tr>

 *       <th scope="row" style="text-weight: normal" rowspan=6>{@code time}

 *       <th scope="row" style="text-weight: normal"><i>(none)</i>

 *       <td>{@link DateFormat#getTimeInstance(int,Locale) DateFormat.getTimeInstance}{@code (}{@link DateFormat#DEFAULT}{@code , getLocale())}

 *    <tr>

 *       <th scope="row" style="text-weight: normal">{@code short}

 *       <td>{@link DateFormat#getTimeInstance(int,Locale) DateFormat.getTimeInstance}{@code (}{@link DateFormat#SHORT}{@code , getLocale())}

 *    <tr>

 *       <th scope="row" style="text-weight: normal">{@code medium}

 *       <td>{@link DateFormat#getTimeInstance(int,Locale) DateFormat.getTimeInstance}{@code (}{@link DateFormat#DEFAULT}{@code , getLocale())}

 *    <tr>

 *       <th scope="row" style="text-weight: normal">{@code long}

 *       <td>{@link DateFormat#getTimeInstance(int,Locale) DateFormat.getTimeInstance}{@code (}{@link DateFormat#LONG}{@code , getLocale())}

 *    <tr>

 *       <th scope="row" style="text-weight: normal">{@code full}

 *       <td>{@link DateFormat#getTimeInstance(int,Locale) DateFormat.getTimeInstance}{@code (}{@link DateFormat#FULL}{@code , getLocale())}

 *    <tr>

 *       <th scope="row" style="text-weight: normal"><i>SubformatPattern</i>

 *       <td>{@code new} {@link SimpleDateFormat#SimpleDateFormat(String,Locale) SimpleDateFormat}{@code (subformatPattern, getLocale())}

 *    <tr>

 *       <th scope="row" style="text-weight: normal">{@code choice}

 *       <th scope="row" style="text-weight: normal"><i>SubformatPattern</i>

 *       <td>{@code new} {@link ChoiceFormat#ChoiceFormat(String) ChoiceFormat}{@code (subformatPattern)}

 * </tbody>

 * </table>

 *

 * <h4>Usage Information</h4>

 *

 * <p>

 * Here are some examples of usage.

 * In real internationalized programs, the message format pattern and other

 * static strings will, of course, be obtained from resource bundles.

 * Other parameters will be dynamically determined at runtime.

 * <p>

 * The first example uses the static method <code>MessageFormat.format</code>,

 * which internally creates a <code>MessageFormat</code> for one-time use:

 * <blockquote><pre>

 * int planet = 7;

 * String event = "a disturbance in the Force";

 *

 * String result = MessageFormat.format(

 *     "At {1,time} on {1,date}, there was {2} on planet {0,number,integer}.",

 *     planet, new Date(), event);

 * </pre></blockquote>

 * The output is:

 * <blockquote><pre>

 * At 12:30 PM on Jul 3, 2053, there was a disturbance in the Force on planet 7.

 * </pre></blockquote>

 *

 * <p>

 * The following example creates a <code>MessageFormat</code> instance that

 * can be used repeatedly:

 * <blockquote><pre>

 * int fileCount = 1273;

 * String diskName = "MyDisk";

 * Object[] testArgs = {new Long(fileCount), diskName};

 *

 * MessageFormat form = new MessageFormat(

 *     "The disk \"{1}\" contains {0} file(s).");

 *

 * System.out.println(form.format(testArgs));

 * </pre></blockquote>

 * The output with different values for <code>fileCount</code>:

 * <blockquote><pre>

 * The disk "MyDisk" contains 0 file(s).

 * The disk "MyDisk" contains 1 file(s).

 * The disk "MyDisk" contains 1,273 file(s).

 * </pre></blockquote>

 *

 * <p>

 * For more sophisticated patterns, you can use a <code>ChoiceFormat</code>

 * to produce correct forms for singular and plural:

 * <blockquote><pre>

 * MessageFormat form = new MessageFormat("The disk \"{1}\" contains {0}.");

 * double[] filelimits = {0,1,2};

 * String[] filepart = {"no files","one file","{0,number} files"};

 * ChoiceFormat fileform = new ChoiceFormat(filelimits, filepart);

 * form.setFormatByArgumentIndex(0, fileform);

 *

 * int fileCount = 1273;

 * String diskName = "MyDisk";

 * Object[] testArgs = {new Long(fileCount), diskName};

 *

 * System.out.println(form.format(testArgs));

 * </pre></blockquote>

 * The output with different values for <code>fileCount</code>:

 * <blockquote><pre>

 * The disk "MyDisk" contains no files.

 * The disk "MyDisk" contains one file.

 * The disk "MyDisk" contains 1,273 files.

 * </pre></blockquote>

 *

 * <p>

 * You can create the <code>ChoiceFormat</code> programmatically, as in the

 * above example, or by using a pattern. See {@link ChoiceFormat}

 * for more information.

 * <blockquote><pre>{@code

 * form.applyPattern(

 *    "There {0,choice,0#are no files|1#is one file|1<are {0,number,integer} files}.");

 * }</pre></blockquote>

 *

 * <p>

 * <strong>Note:</strong> As we see above, the string produced

 * by a <code>ChoiceFormat</code> in <code>MessageFormat</code> is treated as special;

 * occurrences of '{' are used to indicate subformats, and cause recursion.

 * If you create both a <code>MessageFormat</code> and <code>ChoiceFormat</code>

 * programmatically (instead of using the string patterns), then be careful not to

 * produce a format that recurses on itself, which will cause an infinite loop.

 * <p>

 * When a single argument is parsed more than once in the string, the last match

 * will be the final result of the parsing.  For example,

 * <blockquote><pre>

 * MessageFormat mf = new MessageFormat("{0,number,#.##}, {0,number,#.#}");

 * Object[] objs = {new Double(3.1415)};

 * String result = mf.format( objs );

 * // result now equals "3.14, 3.1"

 * objs = null;

 * objs = mf.parse(result, new ParsePosition(0));

 * // objs now equals {new Double(3.1)}

 * </pre></blockquote>

 *

 * <p>

 * Likewise, parsing with a {@code MessageFormat} object using patterns containing

 * multiple occurrences of the same argument would return the last match.  For

 * example,

 * <blockquote><pre>

 * MessageFormat mf = new MessageFormat("{0}, {0}, {0}");

 * String forParsing = "x, y, z";

 * Object[] objs = mf.parse(forParsing, new ParsePosition(0));

 * // result now equals {new String("z")}

 * </pre></blockquote>

 *

 * <h4><a id="synchronization">Synchronization</a></h4>

 *

 * <p>

 * Message formats are not synchronized.

 * It is recommended to create separate format instances for each thread.

 * If multiple threads access a format concurrently, it must be synchronized

 * externally.

 *

 * @see          java.util.Locale

 * @see          Format

 * @see          NumberFormat

 * @see          DecimalFormat

 * @see          DecimalFormatSymbols

 * @see          ChoiceFormat

 * @see          DateFormat

 * @see          SimpleDateFormat

 *

 * @author       Mark Davis

 * @since 1.1

 */

public class MessageFormat extends Format {

    private static final long serialVersionUID = 6479157306784022952L;

    /**

     * Constructs a MessageFormat for the default

     * {@link java.util.Locale.Category#FORMAT FORMAT} locale and the

     * specified pattern.

     * The constructor first sets the locale, then parses the pattern and

     * creates a list of subformats for the format elements contained in it.

     * Patterns and their interpretation are specified in the

     * <a href="#patterns">class description</a>.

     *

     * @param pattern the pattern for this message format

     * @exception IllegalArgumentException if the pattern is invalid

     * @exception NullPointerException if {@code pattern} is

     *            {@code null}

     */

    public MessageFormat(String pattern) {

        this.locale = Locale.getDefault(Locale.Category.FORMAT);

        applyPattern(pattern);

    }

    /**

     * Constructs a MessageFormat for the specified locale and

     * pattern.

     * The constructor first sets the locale, then parses the pattern and

     * creates a list of subformats for the format elements contained in it.

     * Patterns and their interpretation are specified in the

     * <a href="#patterns">class description</a>.

     *

     * @param pattern the pattern for this message format

     * @param locale the locale for this message format

     * @exception IllegalArgumentException if the pattern is invalid

     * @exception NullPointerException if {@code pattern} is

     *            {@code null}

     * @since 1.4

     */

    public MessageFormat(String pattern, Locale locale) {

        this.locale = locale;

        applyPattern(pattern);

    }

    /**

     * Sets the locale to be used when creating or comparing subformats.

     * This affects subsequent calls

     * <ul>

     * <li>to the {@link #applyPattern applyPattern}

     *     and {@link #toPattern toPattern} methods if format elements specify

     *     a format type and therefore have the subformats created in the

     *     <code>applyPattern</code> method, as well as

     * <li>to the <code>format</code> and

     *     {@link #formatToCharacterIterator formatToCharacterIterator} methods

     *     if format elements do not specify a format type and therefore have

     *     the subformats created in the formatting methods.

     * </ul>

     * Subformats that have already been created are not affected.

     *

     * @param locale the locale to be used when creating or comparing subformats

     */

    public void setLocale(Locale locale) {

        this.locale = locale;

    }

    /**

     * Gets the locale that's used when creating or comparing subformats.

     *

     * @return the locale used when creating or comparing subformats

     */

    public Locale getLocale() {

        return locale;

    }

    /**

     * Sets the pattern used by this message format.

     * The method parses the pattern and creates a list of subformats

     * for the format elements contained in it.

     * Patterns and their interpretation are specified in the

     * <a href="#patterns">class description</a>.

     *

     * @param pattern the pattern for this message format

     * @exception IllegalArgumentException if the pattern is invalid

     * @exception NullPointerException if {@code pattern} is

     *            {@code null}

     */

    @SuppressWarnings("fallthrough") // fallthrough in switch is expected, suppress it

    public void applyPattern(String pattern) {

            StringBuilder[] segments = new StringBuilder[4];

            // Allocate only segments[SEG_RAW] here. The rest are

            // allocated on demand.

            segments[SEG_RAW] = new StringBuilder();

            int part = SEG_RAW;

            int formatNumber = 0;

            boolean inQuote = false;

            int braceStack = 0;

            maxOffset = -1;

            for (int i = 0; i < pattern.length(); ++i) {

                char ch = pattern.charAt(i);

                if (part == SEG_RAW) {

                    if (ch == '\'') {

                        if (i + 1 < pattern.length()

                            && pattern.charAt(i+1) == '\'') {

                            segments[part].append(ch);  // handle doubles

                            ++i;

                        } else {

                            inQuote = !inQuote;

                        }

                    } else if (ch == '{' && !inQuote) {

                        part = SEG_INDEX;

                        if (segments[SEG_INDEX] == null) {

                            segments[SEG_INDEX] = new StringBuilder();

                        }

                    } else {

                        segments[part].append(ch);

                    }

                } else  {

                    if (inQuote) {              // just copy quotes in parts

                        segments[part].append(ch);

                        if (ch == '\'') {

                            inQuote = false;

                        }

                    } else {

                        switch (ch) {

                        case ',':

                            if (part < SEG_MODIFIER) {

                                if (segments[++part] == null) {

                                    segments[part] = new StringBuilder();

                                }

                            } else {

                                segments[part].append(ch);

                            }

                            break;

                        case '{':

                            ++braceStack;

                            segments[part].append(ch);

                            break;

                        case '}':

                            if (braceStack == 0) {

                                part = SEG_RAW;

                                makeFormat(i, formatNumber, segments);

                                formatNumber++;

                                // throw away other segments

                                segments[SEG_INDEX] = null;

                                segments[SEG_TYPE] = null;

                                segments[SEG_MODIFIER] = null;

                            } else {

                                --braceStack;

                                segments[part].append(ch);

                            }

                            break;

                        case ' ':

                            // Skip any leading space chars for SEG_TYPE.

                            if (part != SEG_TYPE || segments[SEG_TYPE].length() > 0) {

                                segments[part].append(ch);

                            }

                            break;

                        case '\'':

                            inQuote = true;

                            // fall through, so we keep quotes in other parts