8308108: Support Unicode extension for collation settings

Reviewed-by: iris, rriggs, jlu, alanb

src/java.base/share/classes/java/text/Collator.java

@@ -226,7 +226,43 @@ public static synchronized Collator getInstance() {
     }
 
     /**
-     * Gets the Collator for the desired locale.
+     * Gets the Collator for the desired locale. If the desired locale
+     * has the "{@code ks}" and/or the "{@code kk}"
+     * <a href="https://www.unicode.org/reports/tr35/tr35-collation.html#Setting_Options">
+     * Unicode collation settings</a>, this method will call {@linkplain #setStrength(int)}
+     * and/or {@linkplain #setDecomposition(int)} on the created instance, if the specified
+     * Unicode collation settings are recognized based on the following mappings:
+     * <table class="striped">
+     * <caption style="display:none">Strength/Decomposition mappings</caption>
+     * <thead>
+     * <tr><th scope="col">BCP 47 values for strength (ks)</th>
+     *     <th scope="col">Collator constants for strength</th></tr>
+     * </thead>
+     * <tbody>
+     * <tr><th scope="row" style="text-align:left">level1</th>
+     *     <td>PRIMARY</td></tr>
+     * <tr><th scope="row" style="text-align:left">level2</th>
+     *     <td>SECONDARY</td></tr>
+     * <tr><th scope="row" style="text-align:left">level3</th>
+     *     <td>TERTIARY</td></tr>
+     * <tr><th scope="row" style="text-align:left">identic</th>
+     *     <td>IDENTICAL</td></tr>
+     * </tbody>
+     * <thead>
+     * <tr><th scope="col">BCP 47 values for normalization (kk)</th>
+     *     <th scope="col">Collator constants for decomposition</th></tr>
+     * </thead>
+     * <tbody>
+     * <tr><th scope="row" style="text-align:left">true</th>
+     *     <td>CANONICAL_DECOMPOSITION</td></tr>
+     * <tr><th scope="row" style="text-align:left">false</th>
+     *     <td>NO_DECOMPOSITION</td></tr>
+     * </tbody>
+     * </table>
+     * If the specified setting value is not recognized, the strength and/or
+     * decomposition will not be overridden, as if there were no BCP 47 collation
+     * options in the desired locale.
+     *
      * @apiNote Implementations of {@code Collator} class may produce
      * different instances based on the "{@code co}"
      * <a href="https://www.unicode.org/reports/tr35/#UnicodeCollationIdentifier">
@@ -258,6 +294,27 @@ public static Collator getInstance(Locale desiredLocale) {
                 result = LocaleProviderAdapter.forJRE()
                              .getCollatorProvider().getInstance(desiredLocale);
             }
+
+            // Override strength and decomposition with `desiredLocale`, if any
+            var strength = desiredLocale.getUnicodeLocaleType("ks");
+            if (strength != null) {
+                strength = strength.toLowerCase(Locale.ROOT);
+                switch (strength) {
+                    case "level1" -> result.setStrength(PRIMARY);
+                    case "level2" -> result.setStrength(SECONDARY);
+                    case "level3" -> result.setStrength(TERTIARY);
+                    case "identic" -> result.setStrength(IDENTICAL);
+                }
+            }
+            var norm = desiredLocale.getUnicodeLocaleType("kk");
+            if (norm != null) {
+                norm = norm.toLowerCase(Locale.ROOT);
+                switch (norm) {
+                    case "true" -> result.setDecomposition(CANONICAL_DECOMPOSITION);
+                    case "false" -> result.setDecomposition(NO_DECOMPOSITION);
+                }
+            }
+
             while (true) {
                 if (ref != null) {
                     // Remove the empty SoftReference if any

test/jdk/sun/text/resources/Collator/CollationSettingsTests.java

@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) 2023, 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.
+ *
+ * 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
+ * accompanied this code).
+ *
+ * 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,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8308108
+ * @summary Tests for BCP 47 collation settings
+ * @run junit CollationSettingsTests
+ */
+
+import java.text.Collator;
+import java.util.Locale;
+import java.util.stream.Stream;
+import static java.text.Collator.*;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class CollationSettingsTests {
+    private static final Collator ENG_DEF = Collator.getInstance(Locale.ENGLISH);
+
+    private static Stream<Arguments> strengthData() {
+        return Stream.of(
+            Arguments.of(Locale.forLanguageTag("en-u-ks-level1"), PRIMARY),
+            Arguments.of(Locale.forLanguageTag("en-u-ks-level2"), SECONDARY),
+            Arguments.of(Locale.forLanguageTag("en-u-ks-level3"), TERTIARY),
+            Arguments.of(Locale.forLanguageTag("en-u-ks-identic"), IDENTICAL),
+            Arguments.of(Locale.forLanguageTag("en-u-ks-LEVEL1"), PRIMARY),
+            Arguments.of(Locale.forLanguageTag("en-u-ks-LEVEL2"), SECONDARY),
+            Arguments.of(Locale.forLanguageTag("en-u-ks-LEVEL3"), TERTIARY),
+            Arguments.of(Locale.forLanguageTag("en-u-ks-IDENTIC"), IDENTICAL),
+            // unrecognized setting value
+            Arguments.of(Locale.forLanguageTag("en-u-ks-foo"), ENG_DEF.getStrength()),
+            Arguments.of(Locale.forLanguageTag("en-u-ks-level4"), ENG_DEF.getStrength()),
+            Arguments.of(Locale.forLanguageTag("en-u-ks-identical"), ENG_DEF.getStrength())
+        );
+    }
+
+    private static Stream<Arguments> decompData() {
+        return Stream.of(
+            Arguments.of(Locale.forLanguageTag("en-u-kk-true"), CANONICAL_DECOMPOSITION),
+            Arguments.of(Locale.forLanguageTag("en-u-kk-false"), NO_DECOMPOSITION),
+            Arguments.of(Locale.forLanguageTag("en-u-kk-TRUE"), CANONICAL_DECOMPOSITION),
+            Arguments.of(Locale.forLanguageTag("en-u-kk-FALSE"), NO_DECOMPOSITION),
+            // unrecognized setting value
+            Arguments.of(Locale.forLanguageTag("en-u-kk-foo"), ENG_DEF.getDecomposition()),
+            Arguments.of(Locale.forLanguageTag("en-u-kk-truetrue"), ENG_DEF.getDecomposition())
+        );
+    }
+
+    @ParameterizedTest
+    @MethodSource("strengthData")
+    public void testStrength(Locale l, int expected) {
+        assertEquals(expected, Collator.getInstance(l).getStrength());
+    }
+
+    @ParameterizedTest
+    @MethodSource("decompData")
+    public void testDecomposition(Locale l, int expected) {
+        assertEquals(expected, Collator.getInstance(l).getDecomposition());
+    }
+}