Move Builder to Authentication

Leaving the Builder in Authentication allows
authentication implementations to implement Builder
without needing to implement BuildableAuthentication.

Issue gh-18052

core/src/main/java/org/springframework/security/authentication/AbstractAuthenticationToken.java

@@ -28,7 +28,6 @@ import org.jspecify.annotations.Nullable;
 
 import org.springframework.security.core.AuthenticatedPrincipal;
 import org.springframework.security.core.Authentication;
-import org.springframework.security.core.BuildableAuthentication;
 import org.springframework.security.core.CredentialsContainer;
 import org.springframework.security.core.GrantedAuthority;
 import org.springframework.security.core.authority.AuthorityUtils;
@@ -199,15 +198,15 @@ public abstract class AbstractAuthenticationToken implements Authentication, Cre
 	}
 
 	/**
-	 * A common abstract implementation of {@link BuildableAuthentication.Builder}. It
-	 * implements the builder methods that correspond to the {@link Authentication}
-	 * methods that {@link AbstractAuthenticationToken} implements
+	 * A common abstract implementation of {@link Authentication.Builder}. It implements
+	 * the builder methods that correspond to the {@link Authentication} methods that
+	 * {@link AbstractAuthenticationToken} implements
 	 *
 	 * @param <B>
 	 * @since 7.0
 	 */
 	protected abstract static class AbstractAuthenticationBuilder<B extends AbstractAuthenticationBuilder<B>>
-			implements BuildableAuthentication.Builder<B> {
+			implements Authentication.Builder<B> {
 
 		private boolean authenticated;
 

core/src/main/java/org/springframework/security/core/Authentication.java

@@ -19,6 +19,9 @@ package org.springframework.security.core;
 import java.io.Serializable;
 import java.security.Principal;
 import java.util.Collection;
+import java.util.Set;
+import java.util.function.Consumer;
+import java.util.stream.Collectors;
 
 import org.jspecify.annotations.Nullable;
 
@@ -136,4 +139,112 @@ public interface Authentication extends Principal, Serializable {
 	 */
 	void setAuthenticated(boolean isAuthenticated) throws IllegalArgumentException;
 
+	/**
+	 * A builder based on a given {@link BuildableAuthentication} instance
+	 *
+	 * @author Josh Cummings
+	 * @since 7.0
+	 */
+	interface Builder<B extends Builder<B>> {
+
+		/**
+		 * Apply this authentication instance
+		 * <p>
+		 * By default, merges the authorities in the provided {@code authentication} with
+		 * the authentication being built. Only those authorities that haven't already
+		 * been specified to the builder will be added.
+		 * </p>
+		 * @param authentication the {@link Authentication} to appluy
+		 * @return the {@link Builder} for additional configuration
+		 * @see BuildableAuthentication#getAuthorities
+		 */
+		default B authentication(Authentication authentication) {
+			return authorities((a) -> {
+				Set<String> newAuthorities = a.stream()
+					.map(GrantedAuthority::getAuthority)
+					.collect(Collectors.toUnmodifiableSet());
+				for (GrantedAuthority currentAuthority : authentication.getAuthorities()) {
+					if (!newAuthorities.contains(currentAuthority.getAuthority())) {
+						a.add(currentAuthority);
+					}
+				}
+			});
+		}
+
+		/**
+		 * Mutate the authorities with this {@link Consumer}.
+		 * <p>
+		 * Note that since a non-empty set of authorities implies an
+		 * {@link Authentication} is authenticated, this method also marks the
+		 * authentication as {@link #authenticated} by default.
+		 * </p>
+		 * @param authorities a consumer that receives the full set of authorities
+		 * @return the {@link Builder} for additional configuration
+		 * @see Authentication#getAuthorities
+		 */
+		B authorities(Consumer<Collection<GrantedAuthority>> authorities);
+
+		/**
+		 * Use this credential.
+		 * <p>
+		 * Note that since some credentials are insecure to store, this method is
+		 * implemented as unsupported by default. Only implement or use this method if you
+		 * support secure storage of the credential or if your implementation also
+		 * implements {@link CredentialsContainer} and the credentials are thereby erased.
+		 * </p>
+		 * @param credentials the credentials to use
+		 * @return the {@link Builder} for additional configuration
+		 * @see Authentication#getCredentials
+		 */
+		default B credentials(@Nullable Object credentials) {
+			throw new UnsupportedOperationException(
+					String.format("%s does not store credentials", this.getClass().getSimpleName()));
+		}
+
+		/**
+		 * Use this details object.
+		 * <p>
+		 * Implementations may choose to use these {@code details} in combination with any
+		 * principal from the pre-existing {@link Authentication} instance.
+		 * </p>
+		 * @param details the details to use
+		 * @return the {@link Builder} for additional configuration
+		 * @see Authentication#getDetails
+		 */
+		B details(@Nullable Object details);
+
+		/**
+		 * Use this principal.
+		 * <p>
+		 * Note that in many cases, the principal is strongly-typed. Implementations may
+		 * choose to do a type check and are not necessarily expected to allow any object
+		 * as a principal.
+		 * </p>
+		 * <p>
+		 * Implementations may choose to use this {@code principal} in combination with
+		 * any principal from the pre-existing {@link Authentication} instance.
+		 * </p>
+		 * @param principal the principal to use
+		 * @return the {@link Builder} for additional configuration
+		 * @see Authentication#getPrincipal
+		 */
+		B principal(@Nullable Object principal);
+
+		/**
+		 * Mark this authentication as authenticated or not
+		 * @param authenticated whether this is an authenticated {@link Authentication}
+		 * instance
+		 * @return the {@link Builder} for additional configuration
+		 * @see Authentication#isAuthenticated
+		 */
+		B authenticated(boolean authenticated);
+
+		/**
+		 * Build an {@link Authentication} instance
+		 * @return the {@link Authentication} instance
+		 */
+		Authentication build();
+
+	}
+
 }

core/src/main/java/org/springframework/security/core/BuildableAuthentication.java

@@ -16,42 +16,11 @@
 
 package org.springframework.security.core;
 
-import java.util.Collection;
-import java.util.Set;
-import java.util.function.Consumer;
-import java.util.stream.Collectors;
-
-import org.jspecify.annotations.Nullable;
-
-import org.springframework.security.authentication.AuthenticationManager;
-import org.springframework.security.core.context.SecurityContextHolder;
-
 /**
- * Represents the token for an authentication request or for an authenticated principal
- * once the request has been processed by the
- * {@link AuthenticationManager#authenticate(Authentication)} method.
- * <p>
- * Once the request has been authenticated, the <tt>Authentication</tt> will usually be
- * stored in a thread-local <tt>SecurityContext</tt> managed by the
- * {@link SecurityContextHolder} by the authentication mechanism which is being used. An
- * explicit authentication can be achieved, without using one of Spring Security's
- * authentication mechanisms, by creating an <tt>Authentication</tt> instance and using
- * the code:
- *
- * <pre>
- * SecurityContext context = SecurityContextHolder.createEmptyContext();
- * context.setAuthentication(anAuthentication);
- * SecurityContextHolder.setContext(context);
- * </pre>
+ * An {@link Authentication} that is also buildable.
  *
- * Note that unless the <tt>Authentication</tt> has the <tt>authenticated</tt> property
- * set to <tt>true</tt>, it will still be authenticated by any security interceptor (for
- * method or web invocations) which encounters it.
- * <p>
- * In most cases, the framework transparently takes care of managing the security context
- * and authentication objects for you.
- *
- * @author Ben Alex
+ * @author Josh Cummings
+ * @since 7.0
  */
 public interface BuildableAuthentication extends Authentication {
 
@@ -69,118 +38,9 @@ public interface BuildableAuthentication extends Authentication {
 	 * {@link Authentication} interface and that custom information is often contained in
 	 * the {@link Authentication#getPrincipal} value.
 	 * </p>
-	 * @return an {@link Builder} for building a new {@link BuildableAuthentication} based
-	 * on this instance
-	 * @since 7.0
+	 * @return an {@link Builder} for building a new {@link Authentication} based on this
+	 * instance
 	 */
 	Builder<?> toBuilder();
 
-	/**
-	 * A builder based on a given {@link BuildableAuthentication} instance
-	 *
-	 * @author Josh Cummings
-	 * @since 7.0
-	 */
-	interface Builder<B extends Builder<B>> {
-
-		/**
-		 * Apply this authentication instance
-		 * <p>
-		 * By default, merges the authorities in the provided {@code authentication} with
-		 * the authentication being built. Only those authorities that haven't already
-		 * been specified to the builder will be added.
-		 * </p>
-		 * @param authentication the {@link Authentication} to appluy
-		 * @return the {@link Builder} for additional configuration
-		 * @see BuildableAuthentication#getAuthorities
-		 */
-		default B authentication(Authentication authentication) {
-			return authorities((a) -> {
-				Set<String> newAuthorities = a.stream()
-					.map(GrantedAuthority::getAuthority)
-					.collect(Collectors.toUnmodifiableSet());
-				for (GrantedAuthority currentAuthority : authentication.getAuthorities()) {
-					if (!newAuthorities.contains(currentAuthority.getAuthority())) {
-						a.add(currentAuthority);
-					}
-				}
-			});
-		}
-
-		/**
-		 * Mutate the authorities with this {@link Consumer}.
-		 * <p>
-		 * Note that since a non-empty set of authorities implies an
-		 * {@link Authentication} is authenticated, this method also marks the
-		 * authentication as {@link #authenticated} by default.
-		 * </p>
-		 * @param authorities a consumer that receives the full set of authorities
-		 * @return the {@link Builder} for additional configuration
-		 * @see Authentication#getAuthorities
-		 */
-		B authorities(Consumer<Collection<GrantedAuthority>> authorities);
-
-		/**
-		 * Use this credential.
-		 * <p>
-		 * Note that since some credentials are insecure to store, this method is
-		 * implemented as unsupported by default. Only implement or use this method if you
-		 * support secure storage of the credential or if your implementation also
-		 * implements {@link CredentialsContainer} and the credentials are thereby erased.
-		 * </p>
-		 * @param credentials the credentials to use
-		 * @return the {@link Builder} for additional configuration
-		 * @see Authentication#getCredentials
-		 */
-		default B credentials(@Nullable Object credentials) {
-			throw new UnsupportedOperationException(
-					String.format("%s does not store credentials", this.getClass().getSimpleName()));
-		}
-
-		/**
-		 * Use this details object.
-		 * <p>
-		 * Implementations may choose to use these {@code details} in combination with any
-		 * principal from the pre-existing {@link Authentication} instance.
-		 * </p>
-		 * @param details the details to use
-		 * @return the {@link Builder} for additional configuration
-		 * @see Authentication#getDetails
-		 */
-		B details(@Nullable Object details);
-
-		/**
-		 * Use this principal.
-		 * <p>
-		 * Note that in many cases, the principal is strongly-typed. Implementations may
-		 * choose to do a type check and are not necessarily expected to allow any object
-		 * as a principal.
-		 * </p>
-		 * <p>
-		 * Implementations may choose to use this {@code principal} in combination with
-		 * any principal from the pre-existing {@link Authentication} instance.
-		 * </p>
-		 * @param principal the principal to use
-		 * @return the {@link Builder} for additional configuration
-		 * @see Authentication#getPrincipal
-		 */
-		B principal(@Nullable Object principal);
-
-		/**
-		 * Mark this authentication as authenticated or not
-		 * @param authenticated whether this is an authenticated {@link Authentication}
-		 * instance
-		 * @return the {@link Builder} for additional configuration
-		 * @see Authentication#isAuthenticated
-		 */
-		B authenticated(boolean authenticated);
-
-		/**
-		 * Build an {@link Authentication} instance
-		 * @return the {@link Authentication} instance
-		 */
-		Authentication build();
-
-	}
-
 }