Add equals/hashCode methods to ProblemDetail

Closes gh-29606

spring-web/src/main/java/org/springframework/http/ProblemDetail.java

@@ -22,6 +22,7 @@
 
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
+import org.springframework.util.ObjectUtils;
 
 /**
  * Representation for an RFC 7807 problem detail. Includes spec-defined
@@ -40,8 +41,8 @@
  * {@link org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler}.
  *
  * @author Rossen Stoyanchev
+ * @author Juergen Hoeller
  * @since 6.0
- *
  * @see <a href="https://datatracker.ietf.org/doc/html/rfc7807">RFC 7807</a>
  * @see org.springframework.web.ErrorResponse
  * @see org.springframework.web.ErrorResponseException
@@ -108,6 +109,13 @@ public void setType(URI type) {
 		this.type = type;
 	}
 
+	/**
+	 * Return the configured {@link #setType(URI) problem type}.
+	 */
+	public URI getType() {
+		return this.type;
+	}
+
 	/**
 	 * Setter for the {@link #getTitle() problem title}.
 	 * <p>By default, if not explicitly set and the status is well-known, this
@@ -118,6 +126,20 @@ public void setTitle(@Nullable String title) {
 		this.title = title;
 	}
 
+	/**
+	 * Return the configured {@link #setTitle(String) problem title}.
+	 */
+	@Nullable
+	public String getTitle() {
+		if (this.title == null) {
+			HttpStatus httpStatus = HttpStatus.resolve(this.status);
+			if (httpStatus != null) {
+				return httpStatus.getReasonPhrase();
+			}
+		}
+		return this.title;
+	}
+
 	/**
 	 * Setter for the {@link #getStatus() problem status}.
 	 * @param httpStatus the problem status
@@ -134,6 +156,14 @@ public void setStatus(int status) {
 		this.status = status;
 	}
 
+	/**
+	 * Return the status associated with the problem, provided either to the
+	 * constructor or configured via {@link #setStatus(int)}.
+	 */
+	public int getStatus() {
+		return this.status;
+	}
+
 	/**
 	 * Setter for the {@link #getDetail() problem detail}.
 	 * <p>By default, this is not set.
@@ -143,6 +173,14 @@ public void setDetail(@Nullable String detail) {
 		this.detail = detail;
 	}
 
+	/**
+	 * Return the configured {@link #setDetail(String) problem detail}.
+	 */
+	@Nullable
+	public String getDetail() {
+		return this.detail;
+	}
+
 	/**
 	 * Setter for the {@link #getInstance() problem instance}.
 	 * <p>By default, when {@code ProblemDetail} is returned from an
@@ -153,6 +191,14 @@ public void setInstance(@Nullable URI instance) {
 		this.instance = instance;
 	}
 
+	/**
+	 * Return the configured {@link #setInstance(URI) problem instance}.
+	 */
+	@Nullable
+	public URI getInstance() {
+		return this.instance;
+	}
+
 	/**
 	 * Set a "dynamic" property to be added to a generic {@link #getProperties()
 	 * properties map}.
@@ -168,52 +214,6 @@ public void setProperty(String name, Object value) {
 		this.properties.put(name, value);
 	}
 
-
-	/**
-	 * Return the configured {@link #setType(URI) problem type}.
-	 */
-	public URI getType() {
-		return this.type;
-	}
-
-	/**
-	 * Return the configured {@link #setTitle(String) problem title}.
-	 */
-	@Nullable
-	public String getTitle() {
-		if (this.title == null) {
-			HttpStatus httpStatus = HttpStatus.resolve(this.status);
-			if (httpStatus != null) {
-				return httpStatus.getReasonPhrase();
-			}
-		}
-		return this.title;
-	}
-
-	/**
-	 * Return the status associated with the problem, provided either to the
-	 * constructor or configured via {@link #setStatus(int)}.
-	 */
-	public int getStatus() {
-		return this.status;
-	}
-
-	/**
-	 * Return the configured {@link #setDetail(String) problem detail}.
-	 */
-	@Nullable
-	public String getDetail() {
-		return this.detail;
-	}
-
-	/**
-	 * Return the configured {@link #setInstance(URI) problem instance}.
-	 */
-	@Nullable
-	public URI getInstance() {
-		return this.instance;
-	}
-
 	/**
 	 * Return a generic map of properties that are not known ahead of time,
 	 * possibly {@code null} if no properties have been added. To add a property,
@@ -229,6 +229,33 @@ public Map<String, Object> getProperties() {
 	}
 
 
+	@Override
+	public boolean equals(@Nullable Object other) {
+		if (this == other) {
+			return true;
+		}
+		if (!(other instanceof ProblemDetail otherDetail)) {
+			return false;
+		}
+		return (this.type.equals(otherDetail.type) &&
+				ObjectUtils.nullSafeEquals(this.title, otherDetail.title) &&
+				this.status == otherDetail.status &&
+				ObjectUtils.nullSafeEquals(this.detail, otherDetail.detail) &&
+				ObjectUtils.nullSafeEquals(this.instance, otherDetail.instance) &&
+				ObjectUtils.nullSafeEquals(this.properties, otherDetail.properties));
+	}
+
+	@Override
+	public int hashCode() {
+		int result = this.type.hashCode();
+		result = 31 * result + ObjectUtils.nullSafeHashCode(this.title);
+		result = 31 * result + this.status;
+		result = 31 * result + ObjectUtils.nullSafeHashCode(this.detail);
+		result = 31 * result + ObjectUtils.nullSafeHashCode(this.instance);
+		result = 31 * result + ObjectUtils.nullSafeHashCode(this.properties);
+		return result;
+	}
+
 	@Override
 	public String toString() {
 		return getClass().getSimpleName() + "[" + initToStringContent() + "]";
@@ -239,7 +266,7 @@ public String toString() {
 	 * Subclasses can override this to append additional fields.
 	 */
 	protected String initToStringContent() {
-		return "type='" + this.type + "'" +
+		return "type='" + getType() + "'" +
 				", title='" + getTitle() + "'" +
 				", status=" + getStatus() +
 				", detail='" + getDetail() + "'" +

spring-web/src/test/java/org/springframework/http/ProblemDetailTests.java

@@ -0,0 +1,53 @@
+/*
+ * Copyright 2002-2022 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.http;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Unit tests for {@link ProblemDetail}.
+ *
+ * @author Juergen Hoeller
+ */
+class ProblemDetailTests {
+
+	@Test
+	void equalsAndHashCode() {
+		ProblemDetail pd1 = ProblemDetail.forStatus(500);
+		ProblemDetail pd2 = ProblemDetail.forStatus(HttpStatus.INTERNAL_SERVER_ERROR);
+		ProblemDetail pd3 = ProblemDetail.forStatus(HttpStatus.NOT_FOUND);
+		ProblemDetail pd4 = ProblemDetail.forStatusAndDetail(HttpStatus.NOT_FOUND, "some detail");
+
+		assertThat(pd1).isEqualTo(pd2);
+		assertThat(pd2).isEqualTo(pd1);
+		assertThat(pd1.hashCode()).isEqualTo(pd2.hashCode());
+
+		assertThat(pd3).isNotEqualTo(pd4);
+		assertThat(pd4).isNotEqualTo(pd3);
+		assertThat(pd3.hashCode()).isNotEqualTo(pd4.hashCode());
+
+		assertThat(pd1).isNotEqualTo(pd3);
+		assertThat(pd1).isNotEqualTo(pd4);
+		assertThat(pd2).isNotEqualTo(pd3);
+		assertThat(pd2).isNotEqualTo(pd4);
+		assertThat(pd1.hashCode()).isNotEqualTo(pd3.hashCode());
+		assertThat(pd1.hashCode()).isNotEqualTo(pd4.hashCode());
+	}
+
+}