#188 - ENH: Add support for prototype scope (add @prototype)

Field and method injection supported. PreDestroy lifecycle method is not supported and Closable is expected to be handled by application code. PostConstruct lifecycle method will be called.

Author: rbygrave

inject-generator/src/main/java/io/avaje/inject/generator/BeanReader.java

@@ -186,16 +186,29 @@ void buildRegister(Append writer) {
   }
 
   void addLifecycleCallbacks(Append writer, String indent) {
-    if (postConstructMethod != null) {
+    if (postConstructMethod != null && !prototype) {
       writer.append("%s builder.addPostConstruct($bean::%s);", indent, postConstructMethod.getSimpleName()).eol();
     }
     if (preDestroyMethod != null) {
+      prototypeNotSupported(writer, "@PreDestroy");
       writer.append("%s builder.addPreDestroy($bean::%s);", indent, preDestroyMethod.getSimpleName()).eol();
-    } else if (typeReader.isClosable()) {
+    } else if (typeReader.isClosable() && !prototype) {
       writer.append("%s builder.addPreDestroy($bean);", indent).eol();
     }
   }
 
+  void prototypePostConstruct(Append writer, String indent) {
+    if (postConstructMethod != null) {
+      writer.append("%s bean.%s();", indent, postConstructMethod.getSimpleName()).eol();
+    }
+  }
+
+  private void prototypeNotSupported(Append writer, String lifecycle) {
+    if (prototype) {
+      writer.append("        // @Prototype scoped bean does not support %s lifecycle method", lifecycle).eol();
+    }
+  }
+
   private Set<String> importTypes() {
     importTypes.add(Constants.GENERATED);
     importTypes.add(Constants.BUILDER);

inject-generator/src/main/java/io/avaje/inject/generator/FieldReader.java

@@ -29,9 +29,9 @@ void addImports(Set<String> importTypes) {
     importTypes.add(fieldType);
   }
 
-  String builderGetDependency() {
+  String builderGetDependency(String builder) {
     StringBuilder sb = new StringBuilder();
-    sb.append("b.").append(type.getMethod(nullable));
+    sb.append(builder).append(".").append(type.getMethod(nullable));
     sb.append(nm(fieldType)).append(".class");
     if (name != null) {
       sb.append(",\"").append(name).append("\"");

inject-generator/src/main/java/io/avaje/inject/generator/SimpleBeanWriter.java

@@ -16,6 +16,7 @@ class SimpleBeanWriter {
   private static final String CODE_COMMENT = "/**\n * Generated source - dependency injection builder for %s.\n */";
   private static final String CODE_COMMENT_FACTORY = "/**\n * Generated source - dependency injection factory for request scoped %s.\n */";
   private static final String CODE_COMMENT_BUILD = "  /**\n   * Create and register %s.\n   */";
+  private static final String CODE_COMMENT_BUILD_PROVIDER = "  /**\n   * Register %s provider.\n   */";
 
   private final BeanReader beanReader;
   private final ProcessingContext context;
@@ -146,6 +147,7 @@ private void writeAddFor(MethodReader constructor) {
     beanReader.buildAddFor(writer);
     if (beanReader.prototype()) {
       indent += "  ";
+      writer.append("      // prototype scope so register provider").eol();
       writer.append("      builder.registerProvider(() -> {", shortName, shortName).eol();
     }
     writeCreateBean(constructor);
@@ -155,6 +157,7 @@ private void writeAddFor(MethodReader constructor) {
       writeExtraInjection();
     }
     if (beanReader.prototype()) {
+      beanReader.prototypePostConstruct(writer, indent);
       writer.append("        return bean;").eol();
       writer.append("      });", shortName, shortName).eol();
     }
@@ -163,7 +166,11 @@ private void writeAddFor(MethodReader constructor) {
 
   private void writeBuildMethodStart(MethodReader constructor) {
     int providerIndex = 0;
-    writer.append(CODE_COMMENT_BUILD, shortName).eol();
+    if (beanReader.prototype()) {
+      writer.append(CODE_COMMENT_BUILD_PROVIDER, shortName).eol();
+    } else {
+      writer.append(CODE_COMMENT_BUILD, shortName).eol();
+    }
     writer.append("  public static void build(Builder builder");
     for (MethodReader.MethodParam param : constructor.getParams()) {
       if (param.isGenericParam()) {
@@ -188,25 +195,33 @@ private void writeCreateBean(MethodReader constructor) {
   }
 
   private void writeExtraInjection() {
-    writer.append("      builder.addInjector(b -> {").eol();
-    writer.append("        // field and method injection").eol();
+    if (!beanReader.prototype()) {
+      writer.append("      builder.addInjector(b -> {").eol();
+      writer.append("        // field and method injection").eol();
+    }
     injectFields();
     injectMethods();
-    writer.append("      });").eol();
+    if (!beanReader.prototype()) {
+      writer.append("      });").eol();
+    }
   }
 
   private void injectFields() {
+    String bean = beanReader.prototype() ? "bean" : "$bean";
+    String builder = beanReader.prototype() ? "builder" : "b";
     for (FieldReader fieldReader : beanReader.getInjectFields()) {
       String fieldName = fieldReader.getFieldName();
-      String getDependency = fieldReader.builderGetDependency();
-      writer.append("        $bean.%s = %s;", fieldName, getDependency).eol();
+      String getDependency = fieldReader.builderGetDependency(builder);
+      writer.append("        %s.%s = %s;", bean, fieldName, getDependency).eol();
     }
   }
 
   private void injectMethods() {
+    String bean = beanReader.prototype() ? "bean" : "$bean";
+    String builder = beanReader.prototype() ? "builder" : "b";
     for (MethodReader methodReader : beanReader.getInjectMethods()) {
-      writer.append("        $bean.%s(", methodReader.getName());
-      writeMethodParams("b", methodReader);
+      writer.append("        %s.%s(", bean, methodReader.getName());
+      writeMethodParams(builder, methodReader);
     }
   }
 

inject-test/src/test/java/org/example/coffee/prototype/ExtraProto.java

@@ -0,0 +1,50 @@
+package org.example.coffee.prototype;
+
+import io.avaje.inject.PostConstruct;
+import io.avaje.inject.Prototype;
+import jakarta.inject.Inject;
+
+import java.io.Closeable;
+import java.io.IOException;
+
+@Prototype
+public class ExtraProto implements Closeable {
+
+  boolean initRun;
+
+  @Inject
+  MyProto fieldInjected;
+
+  OtherProto methodInjected;
+
+  @Inject
+  void methodInjected(OtherProto methodInjected) {
+    this.methodInjected = methodInjected;
+  }
+
+  @PostConstruct
+  void init() {
+    initRun = true;
+  }
+
+  public MyProto fieldInjected() {
+    return fieldInjected;
+  }
+
+  public OtherProto methodInjected() {
+    return methodInjected;
+  }
+
+  public boolean initRun() {
+    return initRun;
+  }
+
+  @Override
+  public void close() throws IOException {
+
+  }
+
+  // Compilation error expected with PreDestroy
+  // @PreDestroy
+  // void foo() { }
+}

inject-test/src/test/java/org/example/coffee/prototype/ExtraProtoTest.java

@@ -0,0 +1,22 @@
+package org.example.coffee.prototype;
+
+import io.avaje.inject.BeanScope;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class ExtraProtoTest {
+
+  @Test
+  void fieldMethodInjection() {
+    try (BeanScope scope = BeanScope.newBuilder()
+      .build()) {
+
+      ExtraProto extra = scope.get(ExtraProto.class);
+
+      assertThat(extra.fieldInjected()).isNotNull();
+      assertThat(extra.methodInjected()).isNotNull();
+      assertThat(extra.initRun()).isTrue();
+    }
+  }
+}