initial implementation of EarlyFailingFailureReporter

 * changing ValidationFailureReporter to be an abstract class instead of interface; tracking the current schema here
 * moving some failure() overloads into ValidationFailureReporter from CollectingFailureReporter
 * moving some of the #inContextOfSchema() into ValidationFailureReporter, just to track the context schema change
 * implementing and testing EarlyFailingFailureReporter

Author: erosb

core/src/main/java/org/everit/json/schema/CollectingFailureReporter.java

@@ -1,28 +1,14 @@
 package org.everit.json.schema;
 
-import static java.util.Objects.requireNonNull;
-
 import java.util.ArrayList;
 import java.util.List;
 
-class CollectingFailureReporter implements ValidationFailureReporter {
+class CollectingFailureReporter extends ValidationFailureReporter {
 
     private List<ValidationException> failures = new ArrayList<>(1);
 
-    private Schema schema;
-
     CollectingFailureReporter(Schema schema) {
-        this.schema = requireNonNull(schema, "schema cannot be null");
-    }
-
-    @Override
-    public void failure(String message, String keyword) {
-        failures.add(new ValidationException(schema, message, keyword, schema.getSchemaLocation()));
-    }
-
-    @Override
-    public void failure(Class<?> expectedType, Object actualValue) {
-        failures.add(new ValidationException(schema, expectedType, actualValue, "type", schema.getSchemaLocation()));
+        super(schema);
     }
 
     @Override
@@ -35,12 +21,8 @@ public void validationFinished() {
     }
 
     public ValidationException inContextOfSchema(Schema schema, Runnable task) {
-        requireNonNull(schema, "schema cannot be null");
         int failureCountBefore = failures.size();
-        Schema origSchema = this.schema;
-        this.schema = schema;
-        task.run();
-        this.schema = origSchema;
+        super.inContextOfSchema(schema, task);
         int failureCountAfter = failures.size(), newFailureCount = failureCountAfter - failureCountBefore;
         if (newFailureCount == 0) {
             return null;

core/src/main/java/org/everit/json/schema/EarlyFailingFailureReporter.java

@@ -1,21 +1,13 @@
 package org.everit.json.schema;
 
-public class EarlyFailingFailureReporter implements ValidationFailureReporter {
-
-    @Override public void failure(String message, String keyword) {
-
-    }
-
-    @Override public void failure(Class<?> expectedType, Object actualValue) {
+public class EarlyFailingFailureReporter extends ValidationFailureReporter {
 
+    public EarlyFailingFailureReporter(Schema schema) {
+        super(schema);
     }
 
     @Override public void failure(ValidationException exc) {
-
-    }
-
-    @Override public ValidationException inContextOfSchema(Schema schema, Runnable task) {
-        return null;
+        throw exc;
     }
 
     @Override public void validationFinished() {

core/src/main/java/org/everit/json/schema/ValidationFailureReporter.java

@@ -1,21 +1,40 @@
 package org.everit.json.schema;
 
+import static java.util.Objects.requireNonNull;
+
 /**
  * Internal interface receiving validation failures. Implementations are supposed to throw or collect {@link ValidationException} instances.
  * <p>
- * The validation always happens in the context of some "current schema", tracked by implementations.  This {@link Schema} instance will
+ * The validation always happens in the context of some "current schema". This {@link Schema} instance will
  * be the {@link ValidationException#getViolatedSchema() violated schema} of the {@code ValidationException}s created.
  * </p>
  */
-interface ValidationFailureReporter {
+abstract class ValidationFailureReporter {
+
+    protected Schema schema;
+
+    ValidationFailureReporter(Schema schema) {
+        this.schema = requireNonNull(schema, "schema cannot be null");
+    }
 
-    void failure(String message, String keyword);
+    void failure(String message, String keyword) {
+        failure(new ValidationException(schema, message, keyword, schema.getSchemaLocation()));
+    }
 
-    void failure(Class<?> expectedType, Object actualValue);
+    void failure(Class<?> expectedType, Object actualValue) {
+        failure(new ValidationException(schema, expectedType, actualValue, "type", schema.getSchemaLocation()));
+    }
 
-    void failure(ValidationException exc);
+    abstract void failure(ValidationException exc);
 
-    ValidationException inContextOfSchema(Schema schema, Runnable task);
+    ValidationException inContextOfSchema(Schema schema, Runnable task) {
+        requireNonNull(schema, "schema cannot be null");
+        Schema origSchema = this.schema;
+        this.schema = schema;
+        task.run();
+        this.schema = origSchema;
+        return null;
+    }
 
-    void validationFinished();
+    abstract void validationFinished();
 }

core/src/test/java/org/everit/json/schema/EarlyFailingFailureReporterTest.java

@@ -0,0 +1,32 @@
+package org.everit.json.schema;
+
+import static org.junit.Assert.assertSame;
+import static org.junit.Assert.fail;
+
+import org.junit.Test;
+
+public class EarlyFailingFailureReporterTest {
+
+    private EarlyFailingFailureReporter createSubject() {
+        return new EarlyFailingFailureReporter(NullSchema.INSTANCE);
+    }
+
+    @Test
+    public void testFailure() {
+        EarlyFailingFailureReporter subject = createSubject();
+        ValidationException input = new ValidationException(BooleanSchema.INSTANCE, Boolean.class, "string");
+        try {
+            subject.failure(input);
+            fail();
+        } catch (ValidationException e) {
+            assertSame(input, e);
+        }
+    }
+
+    @Test
+    public void testValidationFinished() {
+        // should be no-op
+        createSubject().validationFinished();
+    }
+
+}