GH-29 Add @autoconstruct (#29)

* Add @autoconstruct * Bump version * Fux AutoConstruct targets * Fix targets again * Fix @autoconstruct on methods/constructors parameters * Improve javadocs of @autoconstruct * Improve auto construct bind
FunnyGuilds · Jul 15, 2023 · 73ba49f · 73ba49f
1 parent d9e7961
commit 73ba49f
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Showing 7 changed files with 133 additions and 9 deletions.
diff --git a/di/src/main/java/org/panda_lang/utilities/inject/DefaultInjector.java b/di/src/main/java/org/panda_lang/utilities/inject/DefaultInjector.java
@@ -120,7 +120,7 @@ public MethodInjector forGeneratedMethod(Method method) throws Exception {
     }
 
     @Override
-    public <T> @Nullable T invokeParameter(Parameter parameter, Object... injectorArgs) throws Exception {
+    public <T> @Nullable T invokeParameter(Parameter parameter, Object... injectorArgs) throws Throwable {
         return ObjectUtils.cast(processor.tryFetchValue(processor, new PropertyParameter(parameter), injectorArgs));
     }
 

diff --git a/di/src/main/java/org/panda_lang/utilities/inject/DependencyInjectionException.java b/di/src/main/java/org/panda_lang/utilities/inject/DependencyInjectionException.java
@@ -22,6 +22,10 @@ public final class DependencyInjectionException extends RuntimeException {
         super(message);
     }
 
+    DependencyInjectionException(Throwable cause) {
+        super(cause);
+    }
+
     DependencyInjectionException(String message, Throwable cause) {
         super(message, cause);
     }

diff --git a/di/src/main/java/org/panda_lang/utilities/inject/FieldsInjector.java b/di/src/main/java/org/panda_lang/utilities/inject/FieldsInjector.java
@@ -5,8 +5,8 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import org.panda_lang.utilities.inject.annotations.AutoConstruct;
 import org.panda_lang.utilities.inject.annotations.Inject;
-import org.panda_lang.utilities.inject.annotations.PostConstruct;
 
 public final class FieldsInjector<T> {
 
@@ -22,7 +22,7 @@ public T newInstance(Object... injectorArgs) throws Throwable {
         T instance = constructorInjector.newInstance(injectorArgs);
 
         for (Field field : getAllFields(instance.getClass())) {
-            if (!field.isAnnotationPresent(Inject.class)) {
+            if (!field.isAnnotationPresent(Inject.class) && !field.isAnnotationPresent(AutoConstruct.class)) {
                 continue;
             }
 

diff --git a/di/src/main/java/org/panda_lang/utilities/inject/InjectorProcessor.java b/di/src/main/java/org/panda_lang/utilities/inject/InjectorProcessor.java
@@ -17,6 +17,7 @@
 package org.panda_lang.utilities.inject;
 
 import org.jetbrains.annotations.Nullable;
+import org.panda_lang.utilities.inject.annotations.AutoConstruct;
 import org.panda_lang.utilities.inject.annotations.Injectable;
 import panda.std.Option;
 import panda.utilities.ObjectUtils;
@@ -37,8 +38,19 @@ final class InjectorProcessor {
     private final Injector injector;
     private final Map<Executable, Annotation[]> injectableCache = new HashMap<>();
 
+    private final Bind<Annotation> autoConstructBind;
+
     InjectorProcessor(Injector injector) {
         this.injector = injector;
+
+        this.autoConstructBind = new DefaultBind<>(AutoConstruct.class);
+        this.autoConstructBind.assignHandler((property, annotation, injectorArgs) -> {
+            try {
+                return injector.newInstanceWithFields(property.getType(), injectorArgs);
+            } catch (Throwable ex) {
+                throw new DependencyInjectionException(ex);
+            }
+        });
     }
 
     protected Object[] fetchValues(InjectorCache cache, Object... injectorArgs) throws Exception {
@@ -132,9 +144,12 @@ protected Bind<Annotation>[] fetchBinds(Annotation[] annotations, Executable exe
             Parameter parameter = parameters[index];
 
             Class<?> requiredType = annotation != null ? annotation.annotationType() : parameter.getType();
-            Option<Bind<Annotation>> bindValue = resources.getBind(requiredType);
+            Bind<Annotation> bind = resources.getBind(requiredType).orNull();
+            if (bind == null && parameter.getAnnotation(AutoConstruct.class) != null) {
+                bind = this.autoConstructBind;
+            }
 
-            binds[index] = bindValue.orThrow(() -> {
+            if (bind == null) {
                 String simplifiedParameters = Joiner.on(", ").join(Arrays.stream(executable.getParameters())
                         .map(p -> p.getType().getSimpleName() + " " + p.getName())
                         .collect(Collectors.toList()))
@@ -148,17 +163,24 @@ protected Bind<Annotation>[] fetchBinds(Annotation[] annotations, Executable exe
                         "    in executable: " + executable.getDeclaringClass().getSimpleName() + "#" + executable.getName() + "(" + simplifiedParameters + ")" +
                         System.lineSeparator()
                 );
-            });
+            }
+            binds[index] = bind;
         }
 
         return binds;
     }
 
     protected Bind<Annotation> fetchBind(@Nullable Annotation annotation, Property property) {
         Class<?> requiredType = annotation != null ? annotation.annotationType() : property.getType();
-        return injector.getResources().getBind(requiredType).orThrow(() -> {
+        Bind<Annotation> bind = this.injector.getResources().getBind(requiredType).orNull();
+        if (bind == null && property.getAnnotation(AutoConstruct.class) != null) {
+            bind = this.autoConstructBind;
+        }
+
+        if (bind == null) {
             throw new DependencyInjectionException("Cannot find proper bind for " + property + " property (type " + property.getType() + ")");
-        });
+        }
+        return bind;
     }
 
     protected Collection<BindHandler<Annotation, Object, ?>>[] fetchHandlers(Executable executable) {

diff --git a/di/src/main/java/org/panda_lang/utilities/inject/annotations/AutoConstruct.java b/di/src/main/java/org/panda_lang/utilities/inject/annotations/AutoConstruct.java
@@ -0,0 +1,15 @@
+package org.panda_lang.utilities.inject.annotations;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Marks field/parameter that value instance should be constructed, if no other bind was found
+ */
+@Target({ ElementType.FIELD, ElementType.PARAMETER })
+@Retention(RetentionPolicy.RUNTIME)
+public @interface AutoConstruct {
+
+}
diff --git a/di/src/test/java/org/panda_lang/utilities/inject/annotation/AutoConstructTest.java b/di/src/test/java/org/panda_lang/utilities/inject/annotation/AutoConstructTest.java
@@ -0,0 +1,81 @@
+package org.panda_lang.utilities.inject.annotation;
+
+import org.junit.jupiter.api.Test;
+import org.panda_lang.utilities.inject.DependencyInjection;
+import org.panda_lang.utilities.inject.Injector;
+import org.panda_lang.utilities.inject.annotations.AutoConstruct;
+import org.panda_lang.utilities.inject.annotations.Inject;
+import org.panda_lang.utilities.inject.annotations.PostConstruct;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+final class AutoConstructTest {
+
+    static class Service {
+
+        @AutoConstruct
+        private Repository repository;
+
+        @PostConstruct
+        private void construct() {
+            assertNotNull(this.repository);
+        }
+
+        public void testMethod(@AutoConstruct DataProvider dataProvider) {
+            assertNotNull(dataProvider);
+        }
+
+    }
+
+    static class Repository {
+
+        @AutoConstruct
+        private DataProvider dataProvider;
+
+        @Inject
+        private String testValue;
+
+        @PostConstruct
+        private void construct() {
+            assertEquals("TestString", this.testValue);
+            assertNotNull(this.dataProvider);
+        }
+
+    }
+
+    static class DataProvider {
+
+        @Inject
+        private String testValue;
+
+        @PostConstruct
+        private void construct() {
+            assertEquals("TestString", this.testValue);
+        }
+
+    }
+
+    @Test
+    void shouldCreateInstances() throws Throwable {
+        Injector injector = DependencyInjection.createInjector(resources -> {
+            resources.on(String.class).assignInstance("TestString");
+        });
+
+        injector.newInstanceWithFields(DataProvider.class);
+        injector.newInstanceWithFields(Repository.class);
+        injector.newInstanceWithFields(Service.class);
+    }
+
+    @Test
+    void shouldRunMethod() throws Throwable {
+        Injector injector = DependencyInjection.createInjector(resources -> {
+            resources.on(String.class).assignInstance("TestString");
+        });
+
+        Service service = injector.newInstanceWithFields(Service.class);
+        injector.invokeMethod(Service.class.getMethod("testMethod", DataProvider.class), service);
+    }
+
+}
diff --git a/...g/utilities/inject/PostConstructTest.java → .../inject/annotation/PostConstructTest.java b/...g/utilities/inject/PostConstructTest.java → .../inject/annotation/PostConstructTest.java
@@ -1,6 +1,8 @@
-package org.panda_lang.utilities.inject;
+package org.panda_lang.utilities.inject.annotation;
 
 import org.junit.jupiter.api.Test;
+import org.panda_lang.utilities.inject.DependencyInjection;
+import org.panda_lang.utilities.inject.Injector;
 import org.panda_lang.utilities.inject.annotations.Inject;
 import org.panda_lang.utilities.inject.annotations.PostConstruct;
 import static org.junit.jupiter.api.Assertions.assertEquals;