Use java.util.Function instead of Converter

Fixes gh-4323

config/src/main/java/org/springframework/security/config/annotation/web/configurers/oauth2/client/AuthorizationCodeAuthenticationFilterConfigurer.java

@@ -15,7 +15,6 @@
  */
 package org.springframework.security.config.annotation.web.configurers.oauth2.client;
 
-import org.springframework.core.convert.converter.Converter;
 import org.springframework.http.client.ClientHttpResponse;
 import org.springframework.security.config.annotation.web.HttpSecurityBuilder;
 import org.springframework.security.config.annotation.web.configurers.AbstractAuthenticationFilterConfigurer;
@@ -34,6 +33,7 @@ import org.springframework.util.Assert;
 import java.net.URI;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.function.Function;
 
 /**
  * @author Joe Grandja
@@ -43,7 +43,7 @@ final class AuthorizationCodeAuthenticationFilterConfigurer<H extends HttpSecuri
 
 	private AuthorizationGrantTokenExchanger<AuthorizationCodeAuthenticationToken> authorizationCodeTokenExchanger;
 	private OAuth2UserService userInfoService;
-	private Map<URI, Converter<ClientHttpResponse, ? extends OAuth2User>> userInfoTypeConverters = new HashMap<>();
+	private Map<URI, Function<ClientHttpResponse, ? extends OAuth2User>> userInfoTypeConverters = new HashMap<>();
 
 
 	AuthorizationCodeAuthenticationFilterConfigurer() {
@@ -71,7 +71,7 @@ final class AuthorizationCodeAuthenticationFilterConfigurer<H extends HttpSecuri
 		return this;
 	}
 
-	AuthorizationCodeAuthenticationFilterConfigurer<H> userInfoTypeConverter(Converter<ClientHttpResponse, ? extends OAuth2User> userInfoConverter, URI userInfoUri) {
+	AuthorizationCodeAuthenticationFilterConfigurer<H> userInfoTypeConverter(Function<ClientHttpResponse, ? extends OAuth2User> userInfoConverter, URI userInfoUri) {
 		Assert.notNull(userInfoConverter, "userInfoConverter cannot be null");
 		Assert.notNull(userInfoUri, "userInfoUri cannot be null");
 		this.userInfoTypeConverters.put(userInfoUri, userInfoConverter);

config/src/main/java/org/springframework/security/config/annotation/web/configurers/oauth2/client/OAuth2LoginConfigurer.java

@@ -16,7 +16,6 @@
 package org.springframework.security.config.annotation.web.configurers.oauth2.client;
 
 import org.springframework.context.ApplicationContext;
-import org.springframework.core.convert.converter.Converter;
 import org.springframework.http.client.ClientHttpResponse;
 import org.springframework.security.config.annotation.web.HttpSecurityBuilder;
 import org.springframework.security.config.annotation.web.configurers.AbstractHttpConfigurer;
@@ -36,6 +35,7 @@ import org.springframework.util.CollectionUtils;
 import java.net.URI;
 import java.util.Arrays;
 import java.util.Map;
+import java.util.function.Function;
 import java.util.stream.Collectors;
 
 /**
@@ -95,7 +95,7 @@ public final class OAuth2LoginConfigurer<B extends HttpSecurityBuilder<B>> exten
 			return this.and();
 		}
 
-		public OAuth2LoginConfigurer<B> userInfoTypeConverter(Converter<ClientHttpResponse, ? extends OAuth2User> userInfoConverter, URI userInfoUri) {
+		public OAuth2LoginConfigurer<B> userInfoTypeConverter(Function<ClientHttpResponse, ? extends OAuth2User> userInfoConverter, URI userInfoUri) {
 			Assert.notNull(userInfoConverter, "userInfoConverter cannot be null");
 			Assert.notNull(userInfoUri, "userInfoUri cannot be null");
 			OAuth2LoginConfigurer.this.authorizationCodeAuthenticationFilterConfigurer.userInfoTypeConverter(userInfoConverter, userInfoUri);

oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/authentication/AuthorizationCodeAuthenticationProcessingFilter.java

@@ -123,7 +123,7 @@ public class AuthorizationCodeAuthenticationProcessingFilter extends AbstractAut
 	public Authentication attemptAuthentication(HttpServletRequest request, HttpServletResponse response)
 			throws AuthenticationException, IOException, ServletException {
 
-		ErrorResponseAttributes authorizationError = this.errorResponseConverter.convert(request);
+		ErrorResponseAttributes authorizationError = this.errorResponseConverter.apply(request);
 		if (authorizationError != null) {
 			OAuth2Error oauth2Error = new OAuth2Error(authorizationError.getErrorCode(),
 					authorizationError.getDescription(), authorizationError.getUri());
@@ -144,7 +144,7 @@ public class AuthorizationCodeAuthenticationProcessingFilter extends AbstractAut
 		}
 
 		AuthorizationCodeAuthorizationResponseAttributes authorizationCodeResponseAttributes =
-				this.authorizationCodeResponseConverter.convert(request);
+				this.authorizationCodeResponseConverter.apply(request);
 
 		AuthorizationCodeAuthenticationToken authRequest = new AuthorizationCodeAuthenticationToken(
 				authorizationCodeResponseAttributes.getCode(), clientRegistration);

oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/user/converter/AbstractOAuth2UserConverter.java

@@ -15,7 +15,6 @@
  */
 package org.springframework.security.oauth2.client.user.converter;
 
-import org.springframework.core.convert.converter.Converter;
 import org.springframework.http.client.ClientHttpResponse;
 import org.springframework.http.converter.HttpMessageConverter;
 import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
@@ -23,9 +22,10 @@ import org.springframework.security.oauth2.core.user.OAuth2User;
 
 import java.io.IOException;
 import java.util.Map;
+import java.util.function.Function;
 
 /**
- * Base implementation of a {@link Converter} that converts a {@link ClientHttpResponse}
+ * Base implementation of a <code>Function</code> that converts a {@link ClientHttpResponse}
  * to a specific type of {@link OAuth2User}.
  *
  * @author Joe Grandja
@@ -33,14 +33,14 @@ import java.util.Map;
  * @see OAuth2User
  * @see ClientHttpResponse
  */
-public abstract class AbstractOAuth2UserConverter<T extends OAuth2User> implements Converter<ClientHttpResponse, T> {
+public abstract class AbstractOAuth2UserConverter<R extends OAuth2User> implements Function<ClientHttpResponse, R> {
 	private final HttpMessageConverter jackson2HttpMessageConverter = new MappingJackson2HttpMessageConverter();
 
 	protected AbstractOAuth2UserConverter() {
 	}
 
 	@Override
-	public final T convert(ClientHttpResponse clientHttpResponse) {
+	public final R apply(ClientHttpResponse clientHttpResponse) {
 		Map<String, Object> userAttributes;
 
 		try {
@@ -49,9 +49,9 @@ public abstract class AbstractOAuth2UserConverter<T extends OAuth2User> implemen
 			throw new IllegalArgumentException("An error occurred reading the UserInfo response: " + ex.getMessage(), ex);
 		}
 
-		return this.convert(userAttributes);
+		return this.apply(userAttributes);
 	}
 
-	protected abstract T convert(Map<String, Object> userAttributes);
+	protected abstract R apply(Map<String, Object> userAttributes);
 
 }

oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/user/converter/CustomOAuth2UserConverter.java

@@ -15,16 +15,17 @@
  */
 package org.springframework.security.oauth2.client.user.converter;
 
-import org.springframework.core.convert.converter.Converter;
 import org.springframework.http.client.ClientHttpResponse;
 import org.springframework.http.converter.HttpMessageConverter;
 import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
 import org.springframework.security.oauth2.core.user.OAuth2User;
+import org.springframework.util.Assert;
 
 import java.io.IOException;
+import java.util.function.Function;
 
 /**
- * An implementation of a {@link Converter} that converts a {@link ClientHttpResponse}
+ * A <code>Function</code> that converts a {@link ClientHttpResponse}
  * to a custom type of {@link OAuth2User}, as supplied via the constructor.
  *
  * @author Joe Grandja
@@ -32,20 +33,21 @@ import java.io.IOException;
  * @see OAuth2User
  * @see ClientHttpResponse
  */
-public final class CustomOAuth2UserConverter<T extends OAuth2User> implements Converter<ClientHttpResponse, T> {
+public final class CustomOAuth2UserConverter<R extends OAuth2User> implements Function<ClientHttpResponse, R> {
 	private final HttpMessageConverter jackson2HttpMessageConverter = new MappingJackson2HttpMessageConverter();
-	private final Class<T> customType;
+	private final Class<R> customType;
 
-	public CustomOAuth2UserConverter(Class<T> customType) {
+	public CustomOAuth2UserConverter(Class<R> customType) {
+		Assert.notNull(customType, "customType cannot be null");
 		this.customType = customType;
 	}
 
 	@Override
-	public T convert(ClientHttpResponse clientHttpResponse) {
-		T user;
+	public R apply(ClientHttpResponse clientHttpResponse) {
+		R user;
 
 		try {
-			user = (T) this.jackson2HttpMessageConverter.read(this.customType, clientHttpResponse);
+			user = (R) this.jackson2HttpMessageConverter.read(this.customType, clientHttpResponse);
 		} catch (IOException ex) {
 			throw new IllegalArgumentException("An error occurred reading the UserInfo response: " + ex.getMessage(), ex);
 		}

oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/user/converter/OAuth2UserConverter.java

@@ -40,7 +40,7 @@ public final class OAuth2UserConverter extends AbstractOAuth2UserConverter<OAuth
 	}
 
 	@Override
-	protected OAuth2User convert(Map<String, Object> userAttributes) {
+	protected OAuth2User apply(Map<String, Object> userAttributes) {
 		return new DefaultOAuth2User(userAttributes, this.nameAttributeKey);
 	}
 }

oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/user/converter/UserInfoConverter.java

@@ -33,7 +33,7 @@ import java.util.Map;
 public final class UserInfoConverter extends AbstractOAuth2UserConverter<UserInfo> {
 
 	@Override
-	protected UserInfo convert(Map<String, Object> userAttributes) {
+	protected UserInfo apply(Map<String, Object> userAttributes) {
 		return new DefaultUserInfo(userAttributes);
 	}
 }

oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/user/converter/package-info.java

@@ -14,7 +14,6 @@
  * limitations under the License.
  */
 /**
- * {@link org.springframework.core.convert.converter.Converter} implementations
- * for {@link org.springframework.security.oauth2.core.user.OAuth2User}.
+ * Support classes for converting to {@link org.springframework.security.oauth2.core.user.OAuth2User}.
  */
 package org.springframework.security.oauth2.client.user.converter;

oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/user/nimbus/NimbusOAuth2UserService.java

@@ -22,7 +22,6 @@ import com.nimbusds.oauth2.sdk.http.HTTPResponse;
 import com.nimbusds.oauth2.sdk.token.BearerAccessToken;
 import com.nimbusds.openid.connect.sdk.UserInfoErrorResponse;
 import com.nimbusds.openid.connect.sdk.UserInfoRequest;
-import org.springframework.core.convert.converter.Converter;
 import org.springframework.http.MediaType;
 import org.springframework.http.client.ClientHttpResponse;
 import org.springframework.security.authentication.AuthenticationServiceException;
@@ -40,13 +39,14 @@ import java.io.IOException;
 import java.net.URI;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.function.Function;
 
 /**
  * An implementation of an {@link OAuth2UserService} that uses the <b>Nimbus OAuth 2.0 SDK</b> internally.
  *
  * <p>
- * This implementation uses a <code>Map</code> of <code>Converter</code>'s <i>keyed</i> by <code>URI</code>.
- * The <code>URI</code> represents the <i>UserInfo Endpoint</i> address and the mapped <code>Converter</code>
+ * This implementation uses a <code>Map</code> of converter's <i>keyed</i> by <code>URI</code>.
+ * The <code>URI</code> represents the <i>UserInfo Endpoint</i> address and the mapped <code>Function</code>
  * is capable of converting the <i>UserInfo Response</i> to either an
  * {@link OAuth2User} (for a standard <i>OAuth 2.0 Provider</i>) or
  * {@link UserInfo} (for an <i>OpenID Connect 1.0 Provider</i>).
@@ -57,14 +57,13 @@ import java.util.Map;
  * @see AuthenticatedPrincipal
  * @see OAuth2User
  * @see UserInfo
- * @see Converter
  * @see <a target="_blank" href="https://connect2id.com/products/nimbus-oauth-openid-connect-sdk">Nimbus OAuth 2.0 SDK</a>
  */
 public class NimbusOAuth2UserService implements OAuth2UserService {
 	private static final String INVALID_USER_INFO_RESPONSE_ERROR_CODE = "invalid_user_info_response";
-	private final Map<URI, Converter<ClientHttpResponse, ? extends OAuth2User>> userInfoTypeConverters;
+	private final Map<URI, Function<ClientHttpResponse, ? extends OAuth2User>> userInfoTypeConverters;
 
-	public NimbusOAuth2UserService(Map<URI, Converter<ClientHttpResponse, ? extends OAuth2User>> userInfoTypeConverters) {
+	public NimbusOAuth2UserService(Map<URI, Function<ClientHttpResponse, ? extends OAuth2User>> userInfoTypeConverters) {
 		Assert.notEmpty(userInfoTypeConverters, "userInfoTypeConverters cannot be empty");
 		this.userInfoTypeConverters = new HashMap<>(userInfoTypeConverters);
 	}
@@ -84,7 +83,7 @@ public class NimbusOAuth2UserService implements OAuth2UserService {
 					clientRegistration.getProviderDetails().getUserInfoUri(), ex);
 			}
 
-			Converter<ClientHttpResponse, ? extends OAuth2User> userInfoConverter = this.userInfoTypeConverters.get(userInfoUri);
+			Function<ClientHttpResponse, ? extends OAuth2User> userInfoConverter = this.userInfoTypeConverters.get(userInfoUri);
 			if (userInfoConverter == null) {
 				throw new IllegalArgumentException("There is no available User Info converter for " + userInfoUri.toString());
 			}
@@ -118,7 +117,7 @@ public class NimbusOAuth2UserService implements OAuth2UserService {
 				throw new OAuth2AuthenticationException(oauth2Error, oauth2Error.toString());
 			}
 
-			user = userInfoConverter.convert(new NimbusClientHttpResponse(httpResponse));
+			user = userInfoConverter.apply(new NimbusClientHttpResponse(httpResponse));
 
 		} catch (ParseException ex) {
 			// This error occurs if the User Info Response is not well-formed or invalid

oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/web/converter/AuthorizationCodeAuthorizationResponseAttributesConverter.java

@@ -15,15 +15,15 @@
  */
 package org.springframework.security.oauth2.client.web.converter;
 
-import org.springframework.core.convert.converter.Converter;
 import org.springframework.security.oauth2.core.endpoint.AuthorizationCodeAuthorizationResponseAttributes;
 import org.springframework.security.oauth2.core.endpoint.OAuth2Parameter;
 import org.springframework.util.Assert;
 
 import javax.servlet.http.HttpServletRequest;
+import java.util.function.Function;
 
 /**
- * An implementation of a {@link Converter} that converts an <i>OAuth 2.0 Authorization Code Grant Response</i>
+ * A <code>Function</code> that converts an <i>OAuth 2.0 Authorization Code Grant Response</i>
  * (in the form of a {@link HttpServletRequest}) to a {@link AuthorizationCodeAuthorizationResponseAttributes}.
  *
  * @author Joe Grandja
@@ -31,10 +31,10 @@ import javax.servlet.http.HttpServletRequest;
  * @see AuthorizationCodeAuthorizationResponseAttributes
  * @see <a target="_blank" href="https://tools.ietf.org/html/rfc6749#section-4.1.2">Section 4.1.2 Authorization Code Grant Response</a>
  */
-public final class AuthorizationCodeAuthorizationResponseAttributesConverter implements Converter<HttpServletRequest, AuthorizationCodeAuthorizationResponseAttributes> {
+public final class AuthorizationCodeAuthorizationResponseAttributesConverter implements Function<HttpServletRequest, AuthorizationCodeAuthorizationResponseAttributes> {
 
 	@Override
-	public AuthorizationCodeAuthorizationResponseAttributes convert(HttpServletRequest request) {
+	public AuthorizationCodeAuthorizationResponseAttributes apply(HttpServletRequest request) {
 		AuthorizationCodeAuthorizationResponseAttributes response;
 
 		String code = request.getParameter(OAuth2Parameter.CODE);

oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/web/converter/ErrorResponseAttributesConverter.java

@@ -15,25 +15,25 @@
  */
 package org.springframework.security.oauth2.client.web.converter;
 
-import org.springframework.core.convert.converter.Converter;
 import org.springframework.security.oauth2.core.endpoint.ErrorResponseAttributes;
 import org.springframework.security.oauth2.core.endpoint.OAuth2Parameter;
 import org.springframework.util.StringUtils;
 
 import javax.servlet.http.HttpServletRequest;
+import java.util.function.Function;
 
 /**
- * An implementation of a {@link Converter} that converts an <i>OAuth 2.0 Error Response</i>
+ * A <code>Function</code> that converts an <i>OAuth 2.0 Error Response</i>
  * (in the form of a {@link HttpServletRequest}) to a {@link ErrorResponseAttributes}.
  *
  * @author Joe Grandja
  * @since 5.0
  * @see ErrorResponseAttributes
  */
-public final class ErrorResponseAttributesConverter implements Converter<HttpServletRequest, ErrorResponseAttributes> {
+public final class ErrorResponseAttributesConverter implements Function<HttpServletRequest, ErrorResponseAttributes> {
 
 	@Override
-	public ErrorResponseAttributes convert(HttpServletRequest request) {
+	public ErrorResponseAttributes apply(HttpServletRequest request) {
 		ErrorResponseAttributes response;
 
 		String errorCode = request.getParameter(OAuth2Parameter.ERROR);

oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/web/converter/package-info.java

@@ -14,7 +14,6 @@
  * limitations under the License.
  */
 /**
- * {@link org.springframework.core.convert.converter.Converter} implementations
- * for <i>OAuth 2.0 Protocol Endpoint Messages</i>.
+ * Support classes for converting <i>OAuth 2.0 Protocol Endpoint Messages</i>.
  */
 package org.springframework.security.oauth2.client.web.converter;

samples/boot/oauth2login/README.adoc

@@ -410,9 +410,9 @@ NOTE: Non-standard scopes may be defined by a standard _OAuth 2.0 Provider_. Ple
 - *authorization-uri* - the URI used by the client to redirect the end-user's user-agent to the _Authorization Server_ in order to obtain authorization from the end-user (the _Resource Owner_).
 - *token-uri* - the URI used by the client when exchanging an _Authorization Grant_ (for example, Authorization Code) for an _Access Token_ at the _Authorization Server_.
 - *user-info-uri* - the URI used by the client to access the protected resource *UserInfo Endpoint*, in order to obtain attributes of the end-user.
-- *user-info-converter* - the `Converter` implementation class used to convert the *UserInfo Response* to a `UserInfo` (_OpenID Connect 1.0 Provider_) or `OAuth2User` instance (_Standard OAuth 2.0 Provider_).
+- *user-info-converter* - the `java.util.function.Function` implementation class used to convert the *UserInfo Response* to a `UserInfo` (_OpenID Connect 1.0 Provider_) or `OAuth2User` instance (_Standard OAuth 2.0 Provider_).
 
-TIP: The `Converter` implementation class for an _OpenID Connect 1.0 Provider_ is *org.springframework.security.oauth2.client.user.converter.UserInfoConverter*
+TIP: The `java.util.function.Function` implementation class for an _OpenID Connect 1.0 Provider_ is *org.springframework.security.oauth2.client.user.converter.UserInfoConverter*
  and for a standard _OAuth 2.0 Provider_ it's *org.springframework.security.oauth2.client.user.converter.OAuth2UserConverter*.
 
 - *user-info-name-attribute-key* - the _key_ used to retrieve the *Name* of the end-user from the `Map` of available attributes in `UserInfo` or `OAuth2User`.

samples/boot/oauth2login/src/main/java/org/springframework/boot/autoconfigure/security/oauth2/client/OAuth2LoginAutoConfiguration.java

@@ -23,7 +23,6 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean
 import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
 import org.springframework.boot.autoconfigure.security.SecurityAutoConfiguration;
 import org.springframework.context.annotation.Configuration;
-import org.springframework.core.convert.converter.Converter;
 import org.springframework.core.env.Environment;
 import org.springframework.http.client.ClientHttpResponse;
 import org.springframework.security.config.annotation.web.builders.HttpSecurity;
@@ -39,6 +38,7 @@ import org.springframework.util.ClassUtils;
 import java.lang.reflect.Constructor;
 import java.net.URI;
 import java.util.Set;
+import java.util.function.Function;
 
 import static org.springframework.boot.autoconfigure.security.oauth2.client.ClientRegistrationAutoConfiguration.CLIENT_PROPERTY_PREFIX;
 import static org.springframework.boot.autoconfigure.security.oauth2.client.ClientRegistrationAutoConfiguration.resolveClientPropertyKeys;
@@ -87,18 +87,18 @@ public class OAuth2LoginAutoConfiguration {
 				String userInfoUriValue = this.environment.getProperty(fullClientPropertyKey + "." + USER_INFO_URI_PROPERTY);
 				String userInfoConverterTypeValue = this.environment.getProperty(fullClientPropertyKey + "." + USER_INFO_CONVERTER_PROPERTY);
 				if (userInfoUriValue != null && userInfoConverterTypeValue != null) {
-					Class<? extends Converter> userInfoConverterType = ClassUtils.resolveClassName(
-						userInfoConverterTypeValue, this.getClass().getClassLoader()).asSubclass(Converter.class);
-					Converter<ClientHttpResponse, ? extends OAuth2User> userInfoConverter = null;
+					Class<? extends Function> userInfoConverterType = ClassUtils.resolveClassName(
+						userInfoConverterTypeValue, this.getClass().getClassLoader()).asSubclass(Function.class);
+					Function<ClientHttpResponse, ? extends OAuth2User> userInfoConverter = null;
 					if (AbstractOAuth2UserConverter.class.isAssignableFrom(userInfoConverterType)) {
-						Constructor<? extends Converter> oauth2UserConverterConstructor = ClassUtils.getConstructorIfAvailable(userInfoConverterType, String.class);
+						Constructor<? extends Function> oauth2UserConverterConstructor = ClassUtils.getConstructorIfAvailable(userInfoConverterType, String.class);
 						if (oauth2UserConverterConstructor != null) {
 							String userInfoNameAttributeKey = this.environment.getProperty(fullClientPropertyKey + "." + USER_INFO_NAME_ATTR_KEY_PROPERTY);
-							userInfoConverter = (Converter<ClientHttpResponse, ? extends OAuth2User>)oauth2UserConverterConstructor.newInstance(userInfoNameAttributeKey);
+							userInfoConverter = (Function<ClientHttpResponse, ? extends OAuth2User>)oauth2UserConverterConstructor.newInstance(userInfoNameAttributeKey);
 						}
 					}
 					if (userInfoConverter == null) {
-						userInfoConverter = (Converter<ClientHttpResponse, ? extends OAuth2User>)userInfoConverterType.newInstance();
+						userInfoConverter = (Function<ClientHttpResponse, ? extends OAuth2User>)userInfoConverterType.newInstance();
 					}
 					oauth2LoginConfigurer.userInfoEndpoint().userInfoTypeConverter(userInfoConverter, new URI(userInfoUriValue));
 				}