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.ExtractorType;
  import org.agorava.api.extractor.TokenExtractor;
  import org.agorava.api.oauth.Token;
  import org.agorava.api.service.Preconditions;
  
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  import static org.agorava.api.extractor.ExtractorType.Type.TOKEN_JSON;
  
  @ExtractorType(TOKEN_JSON)
  public class JsonTokenExtractor implements TokenExtractor {
      private Pattern accessTokenPattern = Pattern.compile("\"access_token\":\\s*\"(\\S*?)\"");
  
      public Token extract(String response) {
          Preconditions.checkEmptyString(response, "Cannot extract a token from a null or empty String");
          Matcher matcher = accessTokenPattern.matcher(response);
          if (matcher.find()) {
              return new Token(matcher.group(1), "");
          } else {
              throw new AgoravaException("Cannot extract an acces token. Response was: " + response);
          }
      }
  
  }
  