Make AbstractProblemResolver primary method abstract

Author: damianmalczewski

problem4j-spring-web/src/main/java/io/github/problem4j/spring/web/parameter/Violation.java

@@ -125,6 +125,6 @@ public int hashCode() {
    */
   @Override
   public String toString() {
-    return "Violation{field='" + field + "', error='" + error + "'}";
+    return "Violation[field=" + field + ", error=" + error + "]";
   }
 }

problem4j-spring-web/src/main/java/io/github/problem4j/spring/web/resolver/AbstractProblemResolver.java

@@ -16,13 +16,8 @@
 
 package io.github.problem4j.spring.web.resolver;
 
-import io.github.problem4j.core.Problem;
-import io.github.problem4j.core.ProblemContext;
 import io.github.problem4j.spring.web.ProblemFormat;
 import org.jspecify.annotations.Nullable;
-import org.springframework.http.HttpHeaders;
-import org.springframework.http.HttpStatus;
-import org.springframework.http.HttpStatusCode;
 
 /**
  * Convenience base class for {@link ProblemResolver}-s.
@@ -69,19 +64,6 @@ public Class<? extends Exception> getExceptionClass() {
     return clazz;
   }
 
-  /**
-   * Default implementation returning a {@link Problem} with {@link
-   * HttpStatus#INTERNAL_SERVER_ERROR}. Subclasses override this to populate fields like {@code
-   * type}, {@code title}, {@code detail}, and extensions.
-   *
-   * @since 3.0.0
-   */
-  @Override
-  public Problem resolve(
-      ProblemContext context, Exception ex, HttpHeaders headers, HttpStatusCode status) {
-    return Problem.of(HttpStatus.INTERNAL_SERVER_ERROR.value());
-  }
-
   /**
    * Applies the configured {@link ProblemFormat} to a detail string.
    *

problem4j-spring-web/src/test/java/io/github/problem4j/spring/web/CachingProblemResolverStoreTest.java

@@ -20,6 +20,8 @@
 import static org.junit.jupiter.api.Assertions.assertSame;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import io.github.problem4j.core.Problem;
+import io.github.problem4j.core.ProblemContext;
 import io.github.problem4j.spring.web.resolver.AbstractProblemResolver;
 import io.github.problem4j.spring.web.resolver.ProblemResolver;
 import java.io.IOException;
@@ -33,6 +35,9 @@
 import java.util.concurrent.Future;
 import java.util.concurrent.atomic.AtomicInteger;
 import org.junit.jupiter.api.Test;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.HttpStatusCode;
 
 class CachingProblemResolverStoreTest {
 
@@ -42,6 +47,12 @@ private static class TestResolver extends AbstractProblemResolver {
     TestResolver(Class<? extends Exception> clazz) {
       super(clazz);
     }
+
+    @Override
+    public Problem resolve(
+        ProblemContext context, Exception ex, HttpHeaders headers, HttpStatusCode status) {
+      return Problem.of(HttpStatus.INTERNAL_SERVER_ERROR.value());
+    }
   }
 
   @Test
@@ -93,6 +104,12 @@ private static class DummyResolver extends AbstractProblemResolver {
     DummyResolver(Class<? extends Exception> clazz) {
       super(clazz);
     }
+
+    @Override
+    public Problem resolve(
+        ProblemContext context, Exception ex, HttpHeaders headers, HttpStatusCode status) {
+      return Problem.of(HttpStatus.INTERNAL_SERVER_ERROR.value());
+    }
   }
 
   @Test

problem4j-spring-web/src/test/java/io/github/problem4j/spring/web/DefaultProblemResolverStoreTest.java

@@ -19,12 +19,17 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import io.github.problem4j.core.Problem;
+import io.github.problem4j.core.ProblemContext;
 import io.github.problem4j.spring.web.resolver.AbstractProblemResolver;
 import io.github.problem4j.spring.web.resolver.ProblemResolver;
 import java.util.List;
 import java.util.Optional;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.HttpStatusCode;
 
 class DefaultProblemResolverStoreTest {
 
@@ -40,6 +45,12 @@ private static class TestResolver extends AbstractProblemResolver {
     TestResolver(Class<? extends Exception> clazz) {
       super(clazz);
     }
+
+    @Override
+    public Problem resolve(
+        ProblemContext context, Exception ex, HttpHeaders headers, HttpStatusCode status) {
+      return Problem.of(HttpStatus.INTERNAL_SERVER_ERROR.value());
+    }
   }
 
   private ProblemResolverStore store;

problem4j-spring-web/src/test/java/io/github/problem4j/spring/web/resolver/AbstractProblemResolverTest.java

@@ -38,7 +38,14 @@ public static Stream<Arguments> exceptions() {
   @ParameterizedTest
   @MethodSource("exceptions")
   void givenAnyMapping_shouldReturnExceptionClass(Class<? extends Exception> clazz) {
-    AbstractProblemResolver resolver = new AbstractProblemResolver(clazz) {};
+    AbstractProblemResolver resolver =
+        new AbstractProblemResolver(clazz) {
+          @Override
+          public Problem resolve(
+              ProblemContext context, Exception ex, HttpHeaders headers, HttpStatusCode status) {
+            return Problem.of(HttpStatus.INTERNAL_SERVER_ERROR.value());
+          }
+        };
 
     Class<? extends Exception> exceptionClass = resolver.getExceptionClass();
 
@@ -47,7 +54,14 @@ void givenAnyMapping_shouldReturnExceptionClass(Class<? extends Exception> clazz
 
   @Test
   void givenNoResolveProblemOverride_whenResolve_thenReturnsInternalServerError() {
-    AbstractProblemResolver resolver = new AbstractProblemResolver(RuntimeException.class) {};
+    AbstractProblemResolver resolver =
+        new AbstractProblemResolver(RuntimeException.class) {
+          @Override
+          public Problem resolve(
+              ProblemContext context, Exception ex, HttpHeaders headers, HttpStatusCode status) {
+            return Problem.of(HttpStatus.INTERNAL_SERVER_ERROR.value());
+          }
+        };
 
     Problem problem =
         resolver.resolve(