content: /*
   * Copyright (C) 2010-2101 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.
   */
  
  package com.alibaba.otter.shared.common.utils;
  
  import java.util.Map;
  
  import org.apache.commons.lang.StringUtils;
  import org.apache.oro.text.regex.MalformedPatternException;
  import org.apache.oro.text.regex.Pattern;
  import org.apache.oro.text.regex.PatternCompiler;
  import org.apache.oro.text.regex.PatternMatcher;
  import org.apache.oro.text.regex.Perl5Compiler;
  import org.apache.oro.text.regex.Perl5Matcher;
  
  import com.google.common.base.Function;
  import com.google.common.collect.OtterMigrateMap;
  
  /**
   * @author simon 2012-9-25 下午5:01:48
   * @version 4.1.0
   */
  public class RegexUtils {
  
      private static Map<String, Pattern> patterns = null;
  
      static {
          patterns = OtterMigrateMap.makeSoftValueComputingMap(new Function<String, Pattern>() {
  
              public Pattern apply(String pattern) {
                  try {
                      PatternCompiler pc = new Perl5Compiler();
                      return pc.compile(pattern, Perl5Compiler.CASE_INSENSITIVE_MASK | Perl5Compiler.READ_ONLY_MASK);
                  } catch (MalformedPatternException e) {
                      throw new RuntimeException("Regex failed!", e);
                  }
              }
          });
      }
  
      public static String findFirst(String originalStr, String regex) {
          if (StringUtils.isBlank(originalStr) || StringUtils.isBlank(regex)) {
              return StringUtils.EMPTY;
          }
  
          PatternMatcher matcher = new Perl5Matcher();
          if (matcher.contains(originalStr, patterns.get(regex))) {
              return StringUtils.trimToEmpty(matcher.getMatch().group(0));
          }
          return StringUtils.EMPTY;
      }
  }
  