/*
 * (C) 2007-2012 Alibaba Group Holding Limited.
 * 
 * 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.
 * Authors:
 *   wuhua <wq163@163.com> , boyan <killme2008@gmail.com>
 */
package com.taobao.metamorphosis.utils;

import java.util.ArrayList;
import java.util.regex.Matcher;
import java.util.regex.Pattern;


public class PatternUtils {
    /**
     * ��pattern.split���ƣ����Dz���������еĿ��ַ���
     * 
     * @param pattern
     * @param input
     * @return
     */
    public static String[] split(final Pattern pattern, final CharSequence input) {
        return split(pattern, input, 0);
    }


    /**
     * ��pattern.split���ƣ����Dz���������еĿ��ַ���
     * 
     * @param pattern
     * @param input
     * @param limit
     * @return
     */
    public static String[] split(final Pattern pattern, final CharSequence input, final int limit) {
        int index = 0;
        final boolean matchLimited = limit > 0;
        final ArrayList<String> matchList = new ArrayList<String>();
        final Matcher m = pattern.matcher(input);

        // Add segments before each match found
        while (m.find()) {
            if (!matchLimited || matchList.size() < limit - 1) {
                final String match = input.subSequence(index, m.start()).toString();
                matchList.add(match);
                index = m.end();
            }
            else if (matchList.size() == limit - 1) { // last one
                final String match = input.subSequence(index, input.length()).toString();
                matchList.add(match);
                index = m.end();
            }
        }

        // If no match was found, return this
        if (index == 0) {
            return new String[] { input.toString() };
        }

        // Add remaining segment
        if (!matchLimited || matchList.size() < limit) {
            matchList.add(input.subSequence(index, input.length()).toString());
        }

        // Construct result
        final int resultSize = matchList.size();
        // if (limit == 0) {
        // while (resultSize > 0 && matchList.get(resultSize - 1).equals("")) {
        // resultSize--;
        // }
        // }
        final String[] result = new String[resultSize];
        return matchList.subList(0, resultSize).toArray(result);
    }

}