/*
* Copyright (C) 2009 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License
*/
package com.android.providers.contacts;
import com.ibm.icu4jni.text.CollationAttribute;
import com.ibm.icu4jni.text.CollationKey; // TODO: java.text.CollationKey post-froyo
import com.ibm.icu4jni.text.Collator;
import com.ibm.icu4jni.text.RuleBasedCollator;
import java.util.Locale;
/**
* Converts a name to a normalized form by removing all non-letter characters and normalizing
* UNICODE according to http://unicode.org/unicode/reports/tr15
*/
public class NameNormalizer {
private static final RuleBasedCollator sCompressingCollator;
static {
sCompressingCollator = (RuleBasedCollator)Collator.getInstance(Locale.getDefault());
sCompressingCollator.setStrength(Collator.PRIMARY);
sCompressingCollator.setDecomposition(Collator.CANONICAL_DECOMPOSITION);
}
private static final RuleBasedCollator sComplexityCollator;
static {
sComplexityCollator = (RuleBasedCollator)Collator.getInstance(Locale.getDefault());
sComplexityCollator.setStrength(Collator.TERTIARY);
sComplexityCollator.setAttribute(CollationAttribute.CASE_FIRST,
CollationAttribute.VALUE_LOWER_FIRST);
}
/**
* Converts the supplied name to a string that can be used to perform approximate matching
* of names. It ignores non-letter characters and removes accents.
*/
public static String normalize(String name) {
CollationKey key = sCompressingCollator.getCollationKey(lettersAndDigitsOnly(name));
return Hex.encodeHex(key.toByteArray(), true);
}
/**
* Compares "complexity" of two names, which is determined by the presence
* of mixed case characters, accents and, if all else is equal, length.
*/
public static int compareComplexity(String name1, String name2) {
int diff = sComplexityCollator.compare(lettersAndDigitsOnly(name1),
lettersAndDigitsOnly(name2));
if (diff != 0) {
return diff;
}
return name1.length() - name2.length();
}
/**
* Returns a string containing just the letters from the original string.
*/
private static String lettersAndDigitsOnly(String name) {
char[] letters = name.toCharArray();
int length = 0;
for (int i = 0; i < letters.length; i++) {
final char c = letters[i];
if (Character.isLetterOrDigit(c)) {
letters[length++] = c;
}
}
if (length != letters.length) {
return new String(letters, 0, length);
}
return name;
}
}