/*
* Copyright 2004-2023 H2 Group. Multiple-Licensed under the MPL 2.0,
* and the EPL 1.0 (https://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.value;
import java.lang.reflect.Method;
import java.text.Collator;
import java.util.Comparator;
import java.util.Locale;
import org.h2.message.DbException;
import org.h2.util.JdbcUtils;
import org.h2.util.StringUtils;
/**
* An implementation of CompareMode that uses the ICU4J Collator.
*/
public class CompareModeIcu4J extends CompareMode {
private final Comparator<String> collator;
private volatile CompareModeIcu4J caseInsensitive;
protected CompareModeIcu4J(String name, int strength) {
super(name, strength);
collator = getIcu4jCollator(name, strength);
}
@Override
public int compareString(String a, String b, boolean ignoreCase) {
if (ignoreCase && getStrength() > Collator.SECONDARY) {
CompareModeIcu4J i = caseInsensitive;
if (i == null) {
caseInsensitive = i = new CompareModeIcu4J(getName(), Collator.SECONDARY);
}
return i.compareString(a, b, false);
}
return collator.compare(a, b);
}
@Override
public boolean equalsChars(String a, int ai, String b, int bi,
boolean ignoreCase) {
return compareString(a.substring(ai, ai + 1), b.substring(bi, bi + 1),
ignoreCase) == 0;
}
@SuppressWarnings("unchecked")
private static Comparator<String> getIcu4jCollator(String name, int strength) {
try {
Comparator<String> result = null;
Class<?> collatorClass = JdbcUtils.loadUserClass(
"com.ibm.icu.text.Collator");
Method getInstanceMethod = collatorClass.getMethod(
"getInstance", Locale.class);
int length = name.length();
if (length == 2) {
Locale locale = new Locale(StringUtils.toLowerEnglish(name), "");
if (compareLocaleNames(locale, name)) {
result = (Comparator<String>) getInstanceMethod.invoke(null, locale);
}
} else if (length == 5) {
// LL_CC (language_country)
int idx = name.indexOf('_');
if (idx >= 0) {
String language = StringUtils.toLowerEnglish(name.substring(0, idx));
String country = name.substring(idx + 1);
Locale locale = new Locale(language, country);
if (compareLocaleNames(locale, name)) {
result = (Comparator<String>) getInstanceMethod.invoke(null, locale);
}
}
}
if (result == null) {
for (Locale locale : (Locale[]) collatorClass.getMethod(
"getAvailableLocales").invoke(null)) {
if (compareLocaleNames(locale, name)) {
result = (Comparator<String>) getInstanceMethod.invoke(null, locale);
break;
}
}
}
if (result == null) {
throw DbException.getInvalidValueException("collator", name);
}
collatorClass.getMethod("setStrength", int.class).invoke(result, strength);
return result;
} catch (Exception e) {
throw DbException.convert(e);
}
}
}