[Payment Request] Update the CurrencyStringFormatter to call the native impl.

chrome/android/java/src/org/chromium/chrome/browser/payments/CurrencyStringFormatter.java

-// Copyright 2016 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-package org.chromium.chrome.browser.payments;
-
-import java.text.DecimalFormatSymbols;
-import java.util.Currency;
-import java.util.Locale;
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
-
-/**
- * Formatter for currency strings that can be too large to parse into numbers.
- * https://w3c.github.io/browser-payment-api/specs/paymentrequest.html#currencyamount
- */
-public class CurrencyStringFormatter {
-    // Amount value pattern and capture group numbers.
-    private static final String AMOUNT_VALUE_PATTERN = "^(-?)([0-9]+)(\\.([0-9]+))?$";
-    private static final int OPTIONAL_NEGATIVE_GROUP = 1;
-    private static final int DIGITS_BETWEEN_NEGATIVE_AND_PERIOD_GROUP = 2;
-    private static final int DIGITS_AFTER_PERIOD_GROUP = 4;
-
-    // Max currency code length. Maximum length of currency code can be at most 2048.
-    private static final int MAX_CURRENCY_CODE_LEN = 2048;
-
-    // Currency code exceeding 6 chars will be ellipsized during formatting for display.
-    private static final int MAX_CURRENCY_CHARS = 6;
-
-    // Unicode character for ellipsis.
-    private static final String ELLIPSIS = "\u2026";
-
-    // Formatting constants.
-    private static final int DIGIT_GROUPING_SIZE = 3;
-
-    private final Pattern mAmountValuePattern;
-
-    /**
-     * The currency formatted for display. Currency can be any string of at most
-     * 2048 characters.Currency code more than 6 character is formatted to first
-     * 5 characters and ellipsis.
-     */
-    public final String mFormattedCurrencyCode;
-
-    /**
-     * The symbol for the currency specified on the bill. For example, the symbol for "USD" is "$".
-     */
-    private final String mCurrencySymbol;
-
-    /**
-     * The number of digits after the decimal separator for the currency specified on the bill. For
-     * example, 2 for "USD" and 0 for "JPY".
-     */
-    private final int mDefaultFractionDigits;
-
-    /**
-     * The number grouping separator for the current locale. For example, "," in US. 3-digit groups
-     * are assumed.
-     */
-    private final char mGroupingSeparator;
-
-    /**
-     * The monetary decimal separator for the current locale. For example, "." in US and "," in
-     * France.
-     */
-    private final char mMonetaryDecimalSeparator;
-
-    /**
-     * Builds the formatter for the given currency code and the current user locale.
-     *
-     * @param currencyCode The currency code. Most commonly, this follows ISO 4217 format: 3 upper
-     *                     case ASCII letters. For example, "USD". Format is not restricted. Should
-     *                     not be null.
-     * @param userLocale User's current locale. Should not be null.
-     */
-    public CurrencyStringFormatter(String currencyCode, Locale userLocale) {
-        assert currencyCode != null : "currencyCode should not be null";
-        assert userLocale != null : "userLocale should not be null";
-
-        mAmountValuePattern = Pattern.compile(AMOUNT_VALUE_PATTERN);
-
-        mFormattedCurrencyCode = currencyCode.length() <= MAX_CURRENCY_CHARS
-                ? currencyCode
-                : currencyCode.substring(0, MAX_CURRENCY_CHARS - 1) + ELLIPSIS;
-
-        String currencySymbol;
-        int defaultFractionDigits;
-        try {
-            Currency currency = Currency.getInstance(currencyCode);
-            currencySymbol = currency.getSymbol();
-            defaultFractionDigits = currency.getDefaultFractionDigits();
-        } catch (IllegalArgumentException e) {
-            // The spec does not limit the currencies to official ISO 4217 currency code list, which
-            // is used by java.util.Currency. For example, "BTX" (bitcoin) is not an official ISO
-            // 4217 currency code, but is allowed by the spec.
-            currencySymbol = "";
-            defaultFractionDigits = 0;
-        }
-
-        // If the prefix of the currency symbol matches the prefix of the currency code, remove the
-        // matching prefix from the symbol. The UI already shows the currency code, so there's no
-        // need to show duplicate information.
-        String symbol = "";
-        for (int i = 0; i < currencySymbol.length(); i++) {
-            if (i >= currencyCode.length() || currencySymbol.charAt(i) != currencyCode.charAt(i)) {
-                symbol = currencySymbol.substring(i);
-                break;
-            }
-        }
-        mCurrencySymbol = symbol;
-
-        mDefaultFractionDigits = defaultFractionDigits;
-
-        // Use the symbols from user's current locale. For example, use "," for decimal separator in
-        // France, even if paying in "USD".
-        DecimalFormatSymbols symbols = new DecimalFormatSymbols(userLocale);
-        mGroupingSeparator = symbols.getGroupingSeparator();
-        mMonetaryDecimalSeparator = symbols.getMonetaryDecimalSeparator();
-    }
-
-    /**
-     * Returns true if the amount value string is in valid format.
-     *
-     * @param amountValue The number to check for validity.
-     * @return Whether the number is in valid format.
-     */
-    public boolean isValidAmountValue(String amountValue) {
-        return amountValue != null && mAmountValuePattern.matcher(amountValue).matches();
-    }
-
-    /**
-     * Returns true if the currency code string is in valid format.
-     *
-     * @param amountCurrencyCode The currency code to check for validity.
-     * @return Whether the currency code is in valid format.
-     */
-    public boolean isValidAmountCurrencyCode(String amountCurrencyCode) {
-        return amountCurrencyCode != null && amountCurrencyCode.length() <= MAX_CURRENCY_CODE_LEN;
-    }
-
-    /** @return The currency code formatted for display. */
-    public String getFormattedCurrencyCode() {
-        return mFormattedCurrencyCode;
-    }
-
-    /**
-     * Formats the currency string for display. Does not parse the string into a number, because it
-     * might be too large. The number is formatted for the current locale and follows the symbol of
-     * the currency code.
-     *
-     * @param amountValue The number to format. Should be in "^-?[0-9]+(\.[0-9]+)?$" format. Should
-     *                    not be null.
-     * @return The currency symbol followed by a space and the formatted number.
-     */
-    public String format(String amountValue) {
-        assert amountValue != null : "amountValue should not be null";
-
-        Matcher m = mAmountValuePattern.matcher(amountValue);
-
-        // Required to capture the groups.
-        boolean matches = m.matches();
-        assert matches;
-
-        StringBuilder result = new StringBuilder(m.group(OPTIONAL_NEGATIVE_GROUP));
-        result.append(mCurrencySymbol);
-        int digitStart = result.length();
-
-        result.append(m.group(DIGITS_BETWEEN_NEGATIVE_AND_PERIOD_GROUP));
-        for (int i = result.length() - DIGIT_GROUPING_SIZE; i > digitStart;
-                i -= DIGIT_GROUPING_SIZE) {
-            result.insert(i, mGroupingSeparator);
-        }
-
-        String decimals = m.group(DIGITS_AFTER_PERIOD_GROUP);
-        int numberOfDecimals = decimals == null ? 0 : decimals.length();
-
-        if (numberOfDecimals > 0 || mDefaultFractionDigits > 0) {
-            result.append(mMonetaryDecimalSeparator);
-            if (null != decimals) result.append(decimals);
-
-            for (int i = numberOfDecimals; i < mDefaultFractionDigits; i++) {
-                result.append("0");
-            }
-        }
-
-        return result.toString();
-    }
-}