content: /*
   * Copyright 2013 Agorava
   *
   * 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 org.agorava.oauth.helpers.extractors;
  
  import org.agorava.api.exception.AgoravaException;
  import org.agorava.api.extractor.TokenExtractor;
  import org.agorava.api.oauth.OAuth;
  import org.agorava.api.oauth.Token;
  import org.agorava.api.service.OAuthEncoder;
  import org.agorava.api.service.Preconditions;
  
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  import static org.agorava.api.oauth.OAuth.OAuthVersion.TWO_FINAL;
  
  /**
   * @author Antoine Sabot-Durand
   */
  @OAuth(TWO_FINAL)
  public class TokenExtractor20Final implements TokenExtractor {
  
      private static final String TOKEN_REGEX = "\"access_token\":\"([^\"]+)";
  
      private static final String EMPTY_SECRET = "";
  
      /**
       * {@inheritDoc}
       */
      public Token extract(String response) {
          Preconditions.checkEmptyString(response, "Response body is incorrect. Can't extract a token from an empty string");
  
          Matcher matcher = Pattern.compile(TOKEN_REGEX).matcher(response);
          if (matcher.find()) {
              String token = OAuthEncoder.decode(matcher.group(1));
              return new Token(token, EMPTY_SECRET);
          } else {
              throw new AgoravaException("Response body is incorrect. Can't extract a token from this: '" + response + "'", null);
          }
  
      }
  }
  