[Core] Rework backend (#1776)

Introduces the backend module. With this module backend
implementations only need to use dependencies from
`io.cucumber.core.backend`. This will allow us to introduce the
module system later on 

The implementation is not yet perfect. Classpath scanning and
resource loading is located in other modules. Removing this
depends on #1526 and removal of type registry configurer which
depends on #1768 .

Fixes #1386 because steps can now see if an exception came from
user code or actual backend.
Removes timeout which would close #1695 earlier then expected.

Author: mpkorstanje

CHANGELOG.md

@@ -25,7 +25,6 @@ Please see [CONTRIBUTING.md](https://github.com/cucumber/cucumber/blob/master/CO
     - cucumber.execution.dry-run
     - cucumber.execution.limit
     - cucumber.execution.order
-    - cucumber.execution.parallel.config.fixed.parallelism
     - cucumber.execution.strict
     - cucumber.execution.wip
     - cucumber.feature
@@ -74,18 +73,16 @@ Please see [CONTRIBUTING.md](https://github.com/cucumber/cucumber/blob/master/CO
     - Adds dedicated `io.cucumber.docstring.DocString` object to use in step definitions
     - Adds `TypeRegistry.defineDocStringType`
     - Adds `@DocStringType` alternative for `TypeRegistry.defineDocStringType`
-
-### Deprecated
- * [Core] Deprecate `timeout` ([#1506](https://github.com/cucumber/cucumber-jvm/issues/1506), [#1694](https://github.com/cucumber/cucumber-jvm/issues/1694) M.P. Korstanje)
-   - Prefer using library based solutions
-    * [JUnit 5 `Assertions.assertTimeout*`](https://junit.org/junit5/docs/5.0.1/api/org/junit/jupiter/api/Assertions.html#assertTimeout-java.time.Duration-org.junit.jupiter.api.function.Executable-)
-    * [Awaitility](https://github.com/awaitility/awaitility)
-    * [Guava `TimeLimiter`](https://github.com/google/guava/blob/master/guava/src/com/google/common/util/concurrent/TimeLimiter.java)
 
 ### Removed
  - [Core] Remove deprecated tag syntax. 
  - [Core] Remove `StepDefinitionReporter` ([#1635](https://github.com/cucumber/cucumber-jvm/issues/1635) M.P. Korstanje, Tim te Beek)
    - Listen `StepDefined` events instead
+ * [Core] Remove `timeout` ([#1506](https://github.com/cucumber/cucumber-jvm/issues/1506), [#1694](https://github.com/cucumber/cucumber-jvm/issues/1694) M.P. Korstanje)
+   - Prefer using library based solutions
+    * [JUnit 5 `Assertions.assertTimeout*`](https://junit.org/junit5/docs/5.0.1/api/org/junit/jupiter/api/Assertions.html#assertTimeout-java.time.Duration-org.junit.jupiter.api.function.Executable-)
+    * [Awaitility](https://github.com/awaitility/awaitility)
+    * [Guava `TimeLimiter`](https://github.com/google/guava/blob/master/guava/src/com/google/common/util/concurrent/TimeLimiter.java)
 
 ### Fixed
  - [Java8] Set default before hook order to the same after hook (1000) 

core/src/main/java/io/cucumber/core/backend/Backend.java

@@ -19,7 +19,7 @@ public interface Backend {
      * Invoked before a new scenario starts. Implementations should do any necessary
      * setup of new, isolated state here. Additional scenario scoped step definitions
      * can be loaded here. These step definitions should implement
-     * {@link io.cucumber.core.runner.ScenarioScoped}
+     * {@link ScenarioScoped}
      */
     void buildWorld();
 

core/src/main/java/io/cucumber/core/backend/BackendProviderService.java

@@ -1,11 +1,12 @@
 package io.cucumber.core.backend;
 
-import io.cucumber.core.io.ResourceLoader;
 import org.apiguardian.api.API;
 
+import java.util.function.Supplier;
+
 @API(status = API.Status.STABLE)
 public interface BackendProviderService {
 
-    Backend create(Lookup lookup, Container container, ResourceLoader resourceLoader);
+    Backend create(Lookup lookup, Container container, Supplier<ClassLoader> classLoader);
 
 }

core/src/main/java/io/cucumber/core/backend/CucumberBackendException.java

@@ -0,0 +1,12 @@
+package io.cucumber.core.backend;
+
+public class CucumberBackendException extends RuntimeException {
+
+    public CucumberBackendException(String message) {
+        super(message);
+    }
+
+    public CucumberBackendException(String message, Throwable cause) {
+        super(message, cause);
+    }
+}

core/src/main/java/io/cucumber/core/backend/CucumberInvocationTargetException.java

@@ -0,0 +1,22 @@
+package io.cucumber.core.backend;
+
+import java.lang.reflect.InvocationTargetException;
+
+public class CucumberInvocationTargetException extends RuntimeException   {
+
+    private final Located located;
+    private final InvocationTargetException invocationTargetException;
+
+    public CucumberInvocationTargetException(Located located, InvocationTargetException invocationTargetException) {
+        this.located = located;
+        this.invocationTargetException = invocationTargetException;
+    }
+
+    public Throwable getInvocationTargetExceptionCause() {
+        return invocationTargetException.getCause();
+    }
+
+    public Located getLocated() {
+        return located;
+    }
+}

core/src/main/java/io/cucumber/core/backend/DataTableTypeDefinition.java

@@ -4,15 +4,7 @@
 import org.apiguardian.api.API;
 
 @API(status = API.Status.STABLE)
-public interface DataTableTypeDefinition {
+public interface DataTableTypeDefinition extends Located {
 
     DataTableType dataTableType();
-
-    /**
-     * The source line where the data table type is defined.
-     * Example: com/example/app/Cucumber.test():42
-     *
-     * @return The source line of the step definition.
-     */
-    String getLocation();
 }

core/src/main/java/io/cucumber/core/backend/DefaultDataTableCellTransformerDefinition.java

@@ -4,16 +4,8 @@
 import org.apiguardian.api.API;
 
 @API(status = API.Status.STABLE)
-public interface DefaultDataTableCellTransformerDefinition {
+public interface DefaultDataTableCellTransformerDefinition extends Located {
 
     TableCellByTypeTransformer tableCellByTypeTransformer();
 
-    /**
-     * The source line where the default data table cell  is defined.
-     * Example: com/example/app/Cucumber.test():42
-     *
-     * @return The source line of the step definition.
-     */
-    String getLocation();
-
 }

core/src/main/java/io/cucumber/core/backend/DefaultDataTableEntryTransformerDefinition.java

@@ -4,17 +4,10 @@
 import org.apiguardian.api.API;
 
 @API(status = API.Status.STABLE)
-public interface DefaultDataTableEntryTransformerDefinition {
+public interface DefaultDataTableEntryTransformerDefinition extends Located {
 
     boolean headersToProperties();
 
     TableEntryByTypeTransformer tableEntryByTypeTransformer();
 
-    /**
-     * The source line where the default table entry transformer is defined.
-     * Example: com/example/app/Cucumber.test():42
-     *
-     * @return The source line of the step definition.
-     */
-    String getLocation();
 }

core/src/main/java/io/cucumber/core/backend/DefaultParameterTransformerDefinition.java

@@ -4,15 +4,7 @@
 import org.apiguardian.api.API;
 
 @API(status = API.Status.STABLE)
-public interface DefaultParameterTransformerDefinition {
+public interface DefaultParameterTransformerDefinition extends Located{
 
     ParameterByTypeTransformer parameterByTypeTransformer();
-
-    /**
-     * The source line where the default parameter transformer is defined.
-     * Example: com/example/app/Cucumber.test():42
-     *
-     * @return The source line of the step definition.
-     */
-    String getLocation();
 }

core/src/main/java/io/cucumber/core/backend/DocStringTypeDefinition.java

@@ -4,15 +4,8 @@
 import org.apiguardian.api.API;
 
 @API(status = API.Status.EXPERIMENTAL)
-public interface DocStringTypeDefinition {
+public interface DocStringTypeDefinition extends Located{
 
     DocStringType docStringType();
 
-    /**
-     * The source line where the parameter type is defined.
-     * Example: com/example/app/Cucumber.test():42
-     *
-     * @return The source line of the step definition.
-     */
-    String getLocation();
 }

core/src/main/java/io/cucumber/core/backend/HookDefinition.java

@@ -3,16 +3,9 @@
 import org.apiguardian.api.API;
 
 @API(status = API.Status.STABLE)
-public interface HookDefinition {
-    /**
-     * The source line where the step definition is defined.
-     * Example: com/example/app/Cucumber.test():42
-     *
-     * @return The source line where the step definition is defined.
-     */
-    String getLocation();
+public interface HookDefinition extends Located {
 
-    void execute(Scenario scenario) throws Throwable;
+    void execute(Scenario scenario);
 
     String getTagExpression();
 

core/src/main/java/io/cucumber/core/backend/Located.java

@@ -0,0 +1,23 @@
+package io.cucumber.core.backend;
+
+import org.apiguardian.api.API;
+
+@API(status = API.Status.STABLE)
+public interface Located {
+
+    /**
+     * @param stackTraceElement The location of the step.
+     * @return Return true if this matches the location. This is used to filter
+     * stack traces.
+     */
+    boolean isDefinedAt(StackTraceElement stackTraceElement);
+
+    /**
+     * The source line where the step definition is defined.
+     * Example: com/example/app/Cucumber.test():42
+     *
+     * @return The source line of the step definition.
+     */
+    String getLocation();
+
+}

core/src/main/java/io/cucumber/core/backend/ParameterTypeDefinition.java

@@ -4,15 +4,8 @@
 import org.apiguardian.api.API;
 
 @API(status = API.Status.EXPERIMENTAL)
-public interface ParameterTypeDefinition {
+public interface ParameterTypeDefinition extends Located {
 
     ParameterType<?> parameterType();
 
-    /**
-     * The source line where the parameter type is defined.
-     * Example: com/example/app/Cucumber.test():42
-     *
-     * @return The source line of the step definition.
-     */
-    String getLocation();
 }

core/src/main/java/io/cucumber/core/backend/ScenarioScoped.java

@@ -0,0 +1,12 @@
+package io.cucumber.core.backend;
+
+/**
+ * Marks a glue class as being scenario scoped.
+ * <p>
+ * Instances of scenario scoped glue can not be used between scenarios and will
+ * be removed from the glue. This is useful when the glue holds a reference to
+ * a scenario scoped object (e.g. a method closure).
+ */
+public interface ScenarioScoped {
+
+}

core/src/main/java/io/cucumber/core/backend/Status.java

@@ -11,21 +11,4 @@ public enum Status {
     AMBIGUOUS,
     FAILED,
     UNUSED;
-
-    public boolean is(Status status) {
-        return this == status;
-    }
-
-    public boolean isOk(boolean isStrict) {
-        return hasAlwaysOkStatus() || !isStrict && hasOkWhenNotStrictStatus();
-    }
-
-    private boolean hasAlwaysOkStatus() {
-        return is(PASSED) || is(SKIPPED);
-    }
-
-    private boolean hasOkWhenNotStrictStatus() {
-        return is(UNDEFINED) || is(PENDING);
-    }
-
 }

core/src/main/java/io/cucumber/core/backend/StepDefinition.java

@@ -5,37 +5,23 @@
 import java.util.List;
 
 @API(status = API.Status.STABLE)
-public interface StepDefinition {
+public interface StepDefinition extends Located {
 
     /**
      * Invokes the step definition. The method should raise a Throwable
      * if the invocation fails, which will cause the step to fail.
      *
      * @param args The arguments for the step
-     * @throws Throwable in case of step failure.
+     * @throws CucumberBackendException          of a failure to invoke the step
+     * @throws CucumberInvocationTargetException in case of a failure in the step.
      */
-    void execute(Object[] args) throws Throwable;
-
-    /**
-     * @param stackTraceElement The location of the step.
-     * @return Return true if this matches the location. This is used to filter
-     * stack traces.
-     */
-    boolean isDefinedAt(StackTraceElement stackTraceElement);
+    void execute(Object[] args) throws CucumberBackendException, CucumberInvocationTargetException;
 
     /**
      * @return parameter information or null when the language does not provide parameter information
      */
     List<ParameterInfo> parameterInfos();
 
-    /**
-     * The source line where the step definition is defined.
-     * Example: com/example/app/Cucumber.test():42
-     *
-     * @return The source line of the step definition.
-     */
-    String getLocation();
-
     /**
      * @return the pattern associated with this instance. Used for error reporting only.
      */

core/src/main/java/io/cucumber/core/options/Constants.java

@@ -44,14 +44,6 @@ public final class Constants {
      */
     public static final String EXECUTION_ORDER_PROPERTY_NAME = "cucumber.execution.order";
 
-    /**
-     * Property name used to determine the desired parallelism for the
-     * {@link Runtime} configuration: {@value}
-     * <p>
-     * No default value; must be an integer.
-     */
-    public static final String EXECUTION_PARALLEL_CONFIG_FIXED_PARALLELISM_PROPERTY_NAME = "cucumber.execution.parallel.config.fixed.parallelism";
-
     /**
      * Property name used to enable strict execution: {@value}
      * <p>

core/src/main/java/io/cucumber/core/options/CucumberPropertiesParser.java

@@ -19,7 +19,6 @@
 import static io.cucumber.core.options.Constants.EXECUTION_DRY_RUN_PROPERTY_NAME;
 import static io.cucumber.core.options.Constants.EXECUTION_LIMIT_PROPERTY_NAME;
 import static io.cucumber.core.options.Constants.EXECUTION_ORDER_PROPERTY_NAME;
-import static io.cucumber.core.options.Constants.EXECUTION_PARALLEL_CONFIG_FIXED_PARALLELISM_PROPERTY_NAME;
 import static io.cucumber.core.options.Constants.EXECUTION_STRICT_PROPERTY_NAME;
 import static io.cucumber.core.options.Constants.FEATURES_PROPERTY_NAME;
 import static io.cucumber.core.options.Constants.FILTER_NAME_PROPERTY_NAME;
@@ -85,12 +84,6 @@ public RuntimeOptionsBuilder parse(Map<String, String> properties) {
             builder::setPickleOrder
         );
 
-        parse(properties,
-            EXECUTION_PARALLEL_CONFIG_FIXED_PARALLELISM_PROPERTY_NAME,
-            Integer::parseInt,
-            builder::setThreads
-        );
-
         parse(properties,
             EXECUTION_STRICT_PROPERTY_NAME,
             Boolean::parseBoolean,

core/src/main/java/io/cucumber/core/reflection/Reflections.java

@@ -1,11 +1,11 @@
 package io.cucumber.core.reflection;
 
-import io.cucumber.core.io.ClassFinder;
 import io.cucumber.core.exception.CucumberException;
+import io.cucumber.core.io.ClassFinder;
 
 import java.lang.reflect.Constructor;
-import java.net.URI;
 import java.lang.reflect.Modifier;
+import java.net.URI;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.HashSet;
@@ -18,7 +18,7 @@ public Reflections(ClassFinder classFinder) {
         this.classFinder = classFinder;
     }
 
-    public static boolean isInstantiable(Class<?> clazz) {
+    static boolean isInstantiable(Class<?> clazz) {
         boolean isNonStaticInnerClass = !Modifier.isStatic(clazz.getModifiers()) && clazz.getEnclosingClass() != null;
         return Modifier.isPublic(clazz.getModifiers()) && !Modifier.isAbstract(clazz.getModifiers()) && !isNonStaticInnerClass;
     }
@@ -28,7 +28,7 @@ public <T> T instantiateExactlyOneSubclass(Class<T> parentType, List<URI> packag
         if (instances.size() == 1) {
             return instances.iterator().next();
         } else if (instances.isEmpty()) {
-            if(fallback != null) {
+            if (fallback != null) {
                 return fallback;
             }
             throw new NoInstancesException(parentType);

core/src/main/java/io/cucumber/core/runner/AmbiguousPickleStepDefinitionsMatch.java

@@ -13,12 +13,12 @@ final class AmbiguousPickleStepDefinitionsMatch extends PickleStepDefinitionMatc
     }
 
     @Override
-    public void runStep(Scenario scenario) {
+    public void runStep(Scenario scenario) throws AmbiguousStepDefinitionsException {
         throw exception;
     }
 
     @Override
-    public void dryRunStep(Scenario scenario) {
+    public void dryRunStep(Scenario scenario) throws AmbiguousStepDefinitionsException {
         runStep(scenario);
     }