From 18a7887737e28811a9904a441e775a4a303782c2 Mon Sep 17 00:00:00 2001
From: Michael Schnell <michael@fuin.org>
Date: Sat, 2 Mar 2024 12:36:14 +0100
Subject: [PATCH] Added new exception for constraint violations

---
 .../core/ConstraintViolationException.java    | 40 +++++++++++++++
 .../ConstraintViolationExceptionTest.java     | 51 +++++++++++++++++++
 2 files changed, 91 insertions(+)
 create mode 100644 core/src/main/java/org/fuin/objects4j/core/ConstraintViolationException.java
 create mode 100644 core/src/test/java/org/fuin/objects4j/core/ConstraintViolationExceptionTest.java

diff --git a/core/src/main/java/org/fuin/objects4j/core/ConstraintViolationException.java b/core/src/main/java/org/fuin/objects4j/core/ConstraintViolationException.java
new file mode 100644
index 0000000..8fa4804
--- /dev/null
+++ b/core/src/main/java/org/fuin/objects4j/core/ConstraintViolationException.java
@@ -0,0 +1,40 @@
+package org.fuin.objects4j.core;
+
+import jakarta.validation.ConstraintViolation;
+import jakarta.validation.constraints.NotEmpty;
+import org.fuin.objects4j.common.Contract;
+
+import java.util.Collections;
+import java.util.Objects;
+import java.util.Set;
+
+/**
+ * On or more constraint violations are considered an error.
+ */
+public final class ConstraintViolationException extends Exception {
+
+    private final Set<ConstraintViolation<Object>> violations;
+
+    /**
+     * Constructor with mandatory data.
+     *
+     * @param violations Violations that caused the error.
+     */
+    public ConstraintViolationException(@NotEmpty final Set<ConstraintViolation<Object>> violations) {
+        super(Contract.asString(violations, ", "));
+        this.violations = Objects.requireNonNull(violations, "violations==null)");
+        if (violations.isEmpty()) {
+            throw new IllegalArgumentException("List of violations is empty");
+        }
+    }
+
+    /**
+     * Returns the violations that caused the error.
+     *
+     * @return Immutable set of violations.
+     */
+    @NotEmpty
+    public Set<ConstraintViolation<Object>> getViolations() {
+        return Collections.unmodifiableSet(violations);
+    }
+}
diff --git a/core/src/test/java/org/fuin/objects4j/core/ConstraintViolationExceptionTest.java b/core/src/test/java/org/fuin/objects4j/core/ConstraintViolationExceptionTest.java
new file mode 100644
index 0000000..1a2f870
--- /dev/null
+++ b/core/src/test/java/org/fuin/objects4j/core/ConstraintViolationExceptionTest.java
@@ -0,0 +1,51 @@
+package org.fuin.objects4j.core;
+
+import jakarta.validation.ConstraintViolation;
+import jakarta.validation.Validation;
+import jakarta.validation.Validator;
+import jakarta.validation.ValidatorFactory;
+import jakarta.validation.constraints.NotEmpty;
+import jakarta.validation.constraints.NotNull;
+import org.junit.jupiter.api.Test;
+
+import java.util.Set;
+
+import static org.assertj.core.api.AssertionsForInterfaceTypes.assertThat;
+
+/**
+ * Test for the {@link ConstraintViolationException} class.
+ */
+class ConstraintViolationExceptionTest {
+
+    @Test
+    void testCreate() {
+
+        // GIVEN
+        try (final ValidatorFactory validatorFactory = Validation.buildDefaultValidatorFactory()) {
+            final Validator validator = validatorFactory.getValidator();
+            final Set<ConstraintViolation<Object>> violations = validator.validate(new Example());
+
+            // WHEN
+            final ConstraintViolationException testee = new ConstraintViolationException(violations);
+
+            // THEN
+            assertThat(testee.getViolations()).containsOnly(violations.toArray(new ConstraintViolation[0]));
+            assertThat(testee.getMessage()).contains("Example.name");
+            assertThat(testee.getMessage()).contains("Example.id");
+
+        }
+
+    }
+
+    private static final class Example {
+
+        @NotNull
+        private Integer id;
+
+        @NotEmpty
+        private String name;
+
+    }
+
+
+}