Generalize SAML 2.0 Assertion Validation Support

Closes gh-8970

Author: jzheaux

saml2/saml2-service-provider/src/main/java/org/springframework/security/saml2/core/Saml2ResponseValidatorResult.java

@@ -0,0 +1,121 @@
+/*
+ * Copyright 2002-2020 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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.springframework.security.saml2.core;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+
+import org.springframework.util.Assert;
+
+/**
+ * A result emitted from a SAML 2.0 Response validation attempt
+ *
+ * @author Josh Cummings
+ * @since 5.4
+ */
+public final class Saml2ResponseValidatorResult {
+	static final Saml2ResponseValidatorResult NO_ERRORS = new Saml2ResponseValidatorResult(Collections.emptyList());
+
+	private final Collection<Saml2Error> errors;
+
+	private Saml2ResponseValidatorResult(Collection<Saml2Error> errors) {
+		Assert.notNull(errors, "errors cannot be null");
+		this.errors = new ArrayList<>(errors);
+	}
+
+	/**
+	 * Say whether this result indicates success
+	 *
+	 * @return whether this result has errors
+	 */
+	public boolean hasErrors() {
+		return !this.errors.isEmpty();
+	}
+
+	/**
+	 * Return error details regarding the validation attempt
+	 *
+	 * @return the collection of results in this result, if any; returns an empty list otherwise
+	 */
+	public Collection<Saml2Error> getErrors() {
+		return Collections.unmodifiableCollection(this.errors);
+	}
+
+	/**
+	 * Return a new {@link Saml2ResponseValidatorResult} that contains
+	 * both the given {@link Saml2Error} and the errors from the result
+	 *
+	 * @param error the {@link Saml2Error} to append
+	 * @return a new {@link Saml2ResponseValidatorResult} for further reporting
+	 */
+	public Saml2ResponseValidatorResult concat(Saml2Error error) {
+		Assert.notNull(error, "error cannot be null");
+		Collection<Saml2Error> errors = new ArrayList<>(this.errors);
+		errors.add(error);
+		return failure(errors);
+	}
+
+	/**
+	 * Return a new {@link Saml2ResponseValidatorResult} that contains
+	 * the errors from the given {@link Saml2ResponseValidatorResult} as well
+	 * as this result.
+	 *
+	 * @param result the {@link Saml2ResponseValidatorResult} to merge with this one
+	 * @return a new {@link Saml2ResponseValidatorResult} for further reporting
+	 */
+	public Saml2ResponseValidatorResult concat(Saml2ResponseValidatorResult result) {
+		Assert.notNull(result, "result cannot be null");
+		Collection<Saml2Error> errors = new ArrayList<>(this.errors);
+		errors.addAll(result.getErrors());
+		return failure(errors);
+	}
+
+	/**
+	 * Construct a successful {@link Saml2ResponseValidatorResult}
+	 *
+	 * @return an {@link Saml2ResponseValidatorResult} with no errors
+	 */
+	public static Saml2ResponseValidatorResult success() {
+		return NO_ERRORS;
+	}
+
+	/**
+	 * Construct a failure {@link Saml2ResponseValidatorResult} with the provided detail
+	 *
+	 * @param errors the list of errors
+	 * @return an {@link Saml2ResponseValidatorResult} with the errors specified
+	 */
+	public static Saml2ResponseValidatorResult failure(Saml2Error... errors) {
+		return failure(Arrays.asList(errors));
+	}
+
+	/**
+	 * Construct a failure {@link Saml2ResponseValidatorResult} with the provided detail
+	 *
+	 * @param errors the list of errors
+	 * @return an {@link Saml2ResponseValidatorResult} with the errors specified
+	 */
+	public static Saml2ResponseValidatorResult failure(Collection<Saml2Error> errors) {
+		if (errors.isEmpty()) {
+			return NO_ERRORS;
+		}
+
+		return new Saml2ResponseValidatorResult(errors);
+	}
+}