Added specific token extractor for OAuth 2.0

src/main/java/org/scribe/extractors/TokenExtractor20Impl.java

@@ -0,0 +1,35 @@
+package org.scribe.extractors;
+
+import java.util.regex.*;
+
+import org.scribe.exceptions.*;
+import org.scribe.model.*;
+import org.scribe.utils.*;
+
+/**
+ * Default implementation of {@AccessTokenExtractor}. Conforms to OAuth 2.0
+ *
+ */
+public class TokenExtractor20Impl implements AccessTokenExtractor
+{
+  private static final String TOKEN_REGEX = "access_token=(\\S*?)(&(\\S*))?";
+  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.matches())
+    {
+      String token = URLUtils.percentDecode(matcher.group(1));
+      return new Token(token, EMPTY_SECRET);
+    } else
+    {
+      throw new OAuthException("Response body is incorrect. Can't extract a token from this: '" + response + "'", null);
+    }
+  }
+}

src/test/java/org/scribe/extractors/TokenExtractor20Test.java

@@ -0,0 +1,59 @@
+package org.scribe.extractors;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.scribe.exceptions.OAuthException;
+import org.scribe.model.Token;
+
+public class TokenExtractor20Test
+{
+
+  private TokenExtractor20Impl extractor;
+
+  @Before
+  public void setup()
+  {
+    extractor = new TokenExtractor20Impl();
+  }
+
+  @Test
+  public void shouldExtractTokenFromOAuthStandardResponse()
+  {
+    String response = "access_token=166942940015970|2.2ltzWXYNDjCtg5ZDVVJJeg__.3600.1295816400-548517159|RsXNdKrpxg8L6QNLWcs2TVTmcaE";
+    Token extracted = extractor.extract(response);
+    assertEquals("166942940015970|2.2ltzWXYNDjCtg5ZDVVJJeg__.3600.1295816400-548517159|RsXNdKrpxg8L6QNLWcs2TVTmcaE", extracted.getToken());
+    assertEquals("", extracted.getSecret());
+  }
+
+  @Test
+  public void shouldExtractTokenFromResponseWithExpiresParam()
+  {
+    String response = "access_token=166942940015970|2.2ltzWXYNDjCtg5ZDVVJJeg__.3600.1295816400-548517159|RsXNdKrpxg8L6QNLWcs2TVTmcaE&expires=5108";
+    Token extracted = extractor.extract(response);
+    assertEquals("166942940015970|2.2ltzWXYNDjCtg5ZDVVJJeg__.3600.1295816400-548517159|RsXNdKrpxg8L6QNLWcs2TVTmcaE", extracted.getToken());
+    assertEquals("", extracted.getSecret());
+  }
+
+  @Test(expected = OAuthException.class)
+  public void shouldThrowExceptionIfTokenIsAbsent()
+  {
+    String response = "&expires=5108";
+    extractor.extract(response);
+  }
+
+  @Test(expected = IllegalArgumentException.class)
+  public void shouldThrowExceptionIfResponseIsNull()
+  {
+    String response = null;
+    extractor.extract(response);
+  }
+
+  @Test(expected = IllegalArgumentException.class)
+  public void shouldThrowExceptionIfResponseIsEmptyString()
+  {
+    String response = "";
+    extractor.extract(response);
+  }
+}