Introduce ProblemStatus as object to assign both title and status at once

Author: malczuuu

src/main/java/io/github/malczuuu/problem4j/core/ProblemBuilder.java

@@ -12,6 +12,8 @@ public interface ProblemBuilder {
 
   ProblemBuilder status(int status);
 
+  ProblemBuilder status(ProblemStatus status);
+
   ProblemBuilder detail(String detail);
 
   ProblemBuilder instance(URI instance);

src/main/java/io/github/malczuuu/problem4j/core/ProblemBuilderImpl.java

@@ -3,6 +3,7 @@
 import java.net.URI;
 import java.util.LinkedHashMap;
 import java.util.Map;
+import java.util.Optional;
 
 final class ProblemBuilderImpl implements ProblemBuilder {
 
@@ -38,6 +39,13 @@ public ProblemBuilder status(int status) {
     return this;
   }
 
+  @Override
+  public ProblemBuilder status(ProblemStatus status) {
+    this.title = status.getTitle();
+    this.status = status.getStatus();
+    return this;
+  }
+
   @Override
   public ProblemBuilder detail(String detail) {
     this.detail = detail;
@@ -62,6 +70,13 @@ public ProblemBuilder extension(String name, Object value) {
   }
 
   public Problem build() {
+    String title = this.title;
+    if (title == null) {
+      Optional<ProblemStatus> status = StatusCode.findValue(this.status);
+      if (status.isPresent()) {
+        title = status.get().getTitle();
+      }
+    }
     return new Problem(type, title, status, detail, instance, extensions);
   }
 }

src/main/java/io/github/malczuuu/problem4j/core/ProblemStatus.java

@@ -0,0 +1,8 @@
+package io.github.malczuuu.problem4j.core;
+
+public interface ProblemStatus {
+
+  String getTitle();
+
+  int getStatus();
+}

src/main/java/io/github/malczuuu/problem4j/core/StatusCode.java

@@ -0,0 +1,110 @@
+package io.github.malczuuu.problem4j.core;
+
+import java.util.Arrays;
+import java.util.Map;
+import java.util.Optional;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+/**
+ * Represents a generic status code, similar to HTTP status codes.
+ *
+ * <p>This enum can be used to represent response status codes in a library-agnostic way, without
+ * introducing dependencies on specific frameworks like Spring.
+ *
+ * @see <a href="https://datatracker.ietf.org/doc/html/rfc9110#name-status-codes">RFC9110 - HTTP
+ *     Semantics</a>
+ * @see <a href="https://http.cat/">HTTP Cats</a>
+ * @see <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Status">HTTP response
+ *     status codes - HTTP | MDN</a>
+ */
+public enum StatusCode implements ProblemStatus {
+  CONTINUE(100, "Continue"),
+  SWITCHING_PROTOCOLS(101, "Switching Protocols"),
+  PROCESSING(102, "Processing"),
+  CHECKPOINT(103, "Checkpoint"),
+  OK(200, "OK"),
+  CREATED(201, "Created"),
+  ACCEPTED(202, "Accepted"),
+  NON_AUTHORITATIVE_INFORMATION(203, "Non-Authoritative Information"),
+  NO_CONTENT(204, "No Content"),
+  RESET_CONTENT(205, "Reset Content"),
+  PARTIAL_CONTENT(206, "Partial Content"),
+  MULTI_STATUS(207, "Multi-Status"),
+  ALREADY_REPORTED(208, "Already Reported"),
+  IM_USED(226, "IM Used"),
+  MULTIPLE_CHOICES(300, "Multiple Choices"),
+  MOVED_PERMANENTLY(301, "Moved Permanently"),
+  FOUND(302, "Found"),
+  SEE_OTHER(303, "See Other"),
+  NOT_MODIFIED(304, "Not Modified"),
+  USE_PROXY(305, "Use Proxy"),
+  TEMPORARY_REDIRECT(307, "Temporary Redirect"),
+  PERMANENT_REDIRECT(308, "Permanent Redirect"),
+  BAD_REQUEST(400, "Bad Request"),
+  UNAUTHORIZED(401, "Unauthorized"),
+  PAYMENT_REQUIRED(402, "Payment Required"),
+  FORBIDDEN(403, "Forbidden"),
+  NOT_FOUND(404, "Not Found"),
+  METHOD_NOT_ALLOWED(405, "Method Not Allowed"),
+  NOT_ACCEPTABLE(406, "Not Acceptable"),
+  PROXY_AUTHENTICATION_REQUIRED(407, "Proxy Authentication Required"),
+  REQUEST_TIMEOUT(408, "Request Timeout"),
+  CONFLICT(409, "Conflict"),
+  GONE(410, "Gone"),
+  LENGTH_REQUIRED(411, "Length Required"),
+  PRECONDITION_FAILED(412, "Precondition Failed"),
+  REQUEST_ENTITY_TOO_LARGE(413, "Request Entity Too Large"),
+  REQUEST_URI_TOO_LONG(414, "Request-URI Too Long"),
+  UNSUPPORTED_MEDIA_TYPE(415, "Unsupported Media Type"),
+  REQUESTED_RANGE_NOT_SATISFIABLE(416, "Requested Range Not Satisfiable"),
+  EXPECTATION_FAILED(417, "Expectation Failed"),
+  I_AM_A_TEAPOT(418, "I'm a teapot"),
+  UNPROCESSABLE_ENTITY(422, "Unprocessable Entity"),
+  LOCKED(423, "Locked"),
+  FAILED_DEPENDENCY(424, "Failed Dependency"),
+  UPGRADE_REQUIRED(426, "Upgrade Required"),
+  PRECONDITION_REQUIRED(428, "Precondition Required"),
+  TOO_MANY_REQUESTS(429, "Too Many Requests"),
+  REQUEST_HEADER_FIELDS_TOO_LARGE(431, "Request Header Fields Too Large"),
+  UNAVAILABLE_FOR_LEGAL_REASONS(451, "Unavailable For Legal Reasons"),
+  INTERNAL_SERVER_ERROR(500, "Internal Server Error"),
+  NOT_IMPLEMENTED(501, "Not Implemented"),
+  BAD_GATEWAY(502, "Bad Gateway"),
+  SERVICE_UNAVAILABLE(503, "Service Unavailable"),
+  GATEWAY_TIMEOUT(504, "Gateway Timeout"),
+  HTTP_VERSION_NOT_SUPPORTED(505, "HTTP Version Not Supported"),
+  VARIANT_ALSO_NEGOTIATES(506, "Variant Also Negotiates"),
+  INSUFFICIENT_STORAGE(507, "Insufficient Storage"),
+  LOOP_DETECTED(508, "Loop Detected"),
+  BANDWIDTH_LIMIT_EXCEEDED(509, "Bandwidth Limit Exceeded"),
+  NOT_EXTENDED(510, "Not Extended"),
+  NETWORK_AUTHENTICATION_REQUIRED(511, "Network Authentication Required"),
+  ;
+
+  private static final Map<Integer, StatusCode> STATUSES =
+      Arrays.stream(values())
+          .collect(Collectors.toMap(ProblemStatus::getStatus, Function.identity()));
+
+  public static Optional<ProblemStatus> findValue(int status) {
+    return Optional.ofNullable(STATUSES.get(status));
+  }
+
+  private final String title;
+  private final int status;
+
+  StatusCode(int status, String title) {
+    this.title = title;
+    this.status = status;
+  }
+
+  @Override
+  public String getTitle() {
+    return title;
+  }
+
+  @Override
+  public int getStatus() {
+    return status;
+  }
+}