org.h2.value.CompareModeDefault Maven / Gradle / Ivy
/*
* Copyright 2004-2022 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.text.CollationKey;
import java.text.Collator;
import org.h2.engine.SysProperties;
import org.h2.message.DbException;
import org.h2.util.SmallLRUCache;
/**
* The default implementation of CompareMode. It uses java.text.Collator.
*/
public class CompareModeDefault extends CompareMode {
private final Collator collator;
private final SmallLRUCache collationKeys;
private volatile CompareModeDefault caseInsensitive;
protected CompareModeDefault(String name, int strength) {
super(name, strength);
collator = CompareMode.getCollator(name);
if (collator == null) {
throw DbException.getInternalError(name);
}
collator.setStrength(strength);
int cacheSize = SysProperties.COLLATOR_CACHE_SIZE;
if (cacheSize != 0) {
collationKeys = SmallLRUCache.newInstance(cacheSize);
} else {
collationKeys = null;
}
}
@Override
public int compareString(String a, String b, boolean ignoreCase) {
if (ignoreCase && getStrength() > Collator.SECONDARY) {
CompareModeDefault i = caseInsensitive;
if (i == null) {
caseInsensitive = i = new CompareModeDefault(getName(), Collator.SECONDARY);
}
return i.compareString(a, b, false);
}
int comp;
if (collationKeys != null) {
CollationKey aKey = getKey(a);
CollationKey bKey = getKey(b);
comp = aKey.compareTo(bKey);
} else {
comp = collator.compare(a, b);
}
return comp;
}
@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;
}
private CollationKey getKey(String a) {
synchronized (collationKeys) {
CollationKey key = collationKeys.get(a);
if (key == null) {
key = collator.getCollationKey(a);
collationKeys.put(a, key);
}
return key;
}
}
}