studio.raptor.sqlparser.fast.value.CompareModeDefault Maven / Gradle / Ivy

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/*
 * Copyright 2004-2014 H2 Group. Multiple-Licensed under the MPL 2.0,
 * and the EPL 1.0 (http://h2database.com/html/license.html).
 * Initial Developer: H2 Group
 */
package studio.raptor.sqlparser.fast.value;

import java.text.CollationKey;
import java.text.Collator;
import studio.raptor.sqlparser.fast.engine.SysProperties;
import studio.raptor.sqlparser.fast.message.ParseException;
import studio.raptor.sqlparser.fast.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;

  protected CompareModeDefault(String name, int strength,
      boolean binaryUnsigned) {
    super(name, strength, binaryUnsigned);
    collator = CompareMode.getCollator(name);
    if (collator == null) {
      throw ParseException.throwInternalError(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) {
      // this is locale sensitive
      a = a.toUpperCase();
      b = b.toUpperCase();
    }
    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;
    }
  }

}