support lazy beans

avaje · Mar 10, 2024 · 7d6a567 · 7d6a567
1 parent b60a009
commit 7d6a567
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Showing 8 changed files with 127 additions and 46 deletions.
diff --git a/inject-generator/src/main/java/io/avaje/inject/generator/BeanReader.java b/inject-generator/src/main/java/io/avaje/inject/generator/BeanReader.java
@@ -32,6 +32,7 @@ final class BeanReader {
   private final boolean prototype;
   private final boolean primary;
   private final boolean secondary;
+  private final boolean lazy;
   private final boolean proxy;
   private final BeanAspects aspects;
   private final BeanConditions conditions = new BeanConditions();
@@ -50,6 +51,7 @@ final class BeanReader {
     this.prototype = PrototypePrism.isPresent(beanType);
     this.primary = PrimaryPrism.isPresent(beanType);
     this.secondary = !primary && SecondaryPrism.isPresent(beanType);
+    this.lazy = !FactoryPrism.isPresent(beanType) && LazyPrism.isPresent(beanType);
     this.typeReader = new TypeReader(UType.parse(beanType.asType()), beanType, importTypes, factory);
 
     typeReader.process();
@@ -110,8 +112,12 @@ BeanAspects aspects() {
     return aspects;
   }
 
-  boolean prototype() {
-    return prototype;
+  boolean registerProvider() {
+    return prototype || lazy;
+  }
+
+  boolean lazy() {
+    return lazy;
   }
 
   boolean importedComponent() {
@@ -261,7 +267,7 @@ void buildAddFor(Append writer) {
   }
 
   void buildRegister(Append writer) {
-    if (prototype) {
+    if (prototype || lazy) {
       return;
     }
     writer.indent("      ");
@@ -278,11 +284,13 @@ void buildRegister(Append writer) {
   }
 
   void addLifecycleCallbacks(Append writer, String indent) {
-    if (postConstructMethod != null && !prototype) {
+
+    if (postConstructMethod != null) {
+      lifeCycleNotSupported("@PostConstruct");
       writer.indent(indent).append(" builder.addPostConstruct($bean::%s);", postConstructMethod.getSimpleName()).eol();
     }
     if (preDestroyMethod != null) {
-      prototypeNotSupported("@PreDestroy");
+      lifeCycleNotSupported("@PreDestroy");
       var priority = preDestroyPriority == null || preDestroyPriority == 1000 ? "" : ", " + preDestroyPriority;
       writer.indent(indent).append(" builder.addPreDestroy($bean::%s%s);", preDestroyMethod.getSimpleName(), priority).eol();
     } else if (typeReader.isClosable() && !prototype) {
@@ -296,9 +304,13 @@ void prototypePostConstruct(Append writer, String indent) {
     }
   }
 
-  private void prototypeNotSupported(String lifecycle) {
-    if (prototype) {
-      logError(beanType, "@Prototype scoped bean does not support %s lifecycle method", lifecycle);
+  private void lifeCycleNotSupported(String lifecycle) {
+    if (registerProvider()) {
+      logError(
+          beanType,
+          "%s scoped bean does not support the %s lifecycle method",
+          prototype ? "@Prototype" : "@Lazy",
+          lifecycle);
     }
   }
 

diff --git a/inject-generator/src/main/java/io/avaje/inject/generator/MethodReader.java b/inject-generator/src/main/java/io/avaje/inject/generator/MethodReader.java
@@ -21,6 +21,7 @@ final class MethodReader {
   private final boolean prototype;
   private final boolean primary;
   private final boolean secondary;
+  private final boolean lazy;
   private final String returnTypeRaw;
   private final UType genericType;
   private final String shortName;
@@ -46,11 +47,13 @@ final class MethodReader {
       prototype = PrototypePrism.isPresent(element);
       primary = PrimaryPrism.isPresent(element);
       secondary = SecondaryPrism.isPresent(element);
+      lazy = LazyPrism.isPresent(element) || LazyPrism.isPresent(element.getEnclosingElement());
       conditions.readAll(element);
     } else {
       prototype = false;
       primary = false;
       secondary = false;
+      lazy = false;
     }
     this.methodName = element.getSimpleName().toString();
     TypeMirror returnMirror = element.getReturnType();
@@ -87,6 +90,9 @@ final class MethodReader {
       this.initMethod = lifecycleReader.initMethod();
       this.destroyMethod = lifecycleReader.destroyMethod();
     }
+    if (lazy && prototype) {
+      APContext.logError("Cannot use both @Lazy and @Prototype");
+    }
   }
 
   @Override
@@ -189,14 +195,14 @@ void builderAddBeanProvider(Append writer) {
       return;
     }
     String indent = "    ";
-    writer.indent(indent).append("  builder.");
+    writer.indent(indent).append("  builder");
     if (prototype) {
-      writer.append("asPrototype()").eol();
+      writer.append(".asPrototype()").eol();
     } else if(secondary) {
-      writer.append("asSecondary()").eol();
+      writer.append(".asSecondary()").eol();
     }
 
-    writer.indent(".registerProvider(() -> {");
+    writer.indent(String.format(".%s(() -> {", lazy ? "registerLazy" : "registerProvider")).eol();
 
     writer.indent(indent).append("    return ");
     writer.append("factory.%s(", methodName);
@@ -451,10 +457,6 @@ void builderGetDependency(Append writer, String builderName) {
       writer.append(")");
     }
 
-    private String providerParam() {
-      return Util.shortName(Util.unwrapProvider(paramType));
-    }
-
     String simpleName() {
       return simpleName;
     }
@@ -542,4 +544,8 @@ Element element() {
       return element;
     }
   }
+
+  public boolean isLazy() {
+    return lazy;
+  }
 }
diff --git a/inject-generator/src/main/java/io/avaje/inject/generator/SimpleBeanWriter.java b/inject-generator/src/main/java/io/avaje/inject/generator/SimpleBeanWriter.java
@@ -147,7 +147,7 @@ private void writeFactoryBeanMethod(MethodReader method) {
     method.buildAddFor(writer);
     method.builderGetFactory(writer, beanReader.hasConditions());
     method.startTry(writer);
-    if (method.isProtoType() || method.isUseProviderForSecondary()) {
+    if (method.isLazy() || method.isProtoType() || method.isUseProviderForSecondary()) {
       method.builderAddBeanProvider(writer);
       method.endTry(writer);
     } else {
@@ -177,9 +177,9 @@ private void writeStaticFactoryMethod() {
   private void writeAddFor(MethodReader constructor) {
     beanReader.buildConditional(writer);
     beanReader.buildAddFor(writer);
-    if (beanReader.prototype()) {
+    if (beanReader.registerProvider()) {
       indent += "  ";
-      writer.append("      builder.asPrototype().registerProvider(() -> {", shortName, shortName).eol();
+      writer.append("      builder.%s(() -> {", beanReader.lazy() ? "registerLazy" : "asPrototype().registerProvider").eol();
     }
     constructor.startTry(writer);
     writeCreateBean(constructor);
@@ -188,7 +188,7 @@ private void writeAddFor(MethodReader constructor) {
     if (beanReader.isExtraInjectionRequired()) {
       writeExtraInjection();
     }
-    if (beanReader.prototype()) {
+    if (beanReader.registerProvider()) {
       beanReader.prototypePostConstruct(writer, indent);
       writer.indent("        return bean;").eol();
       writer.indent("      });").eol();
@@ -198,7 +198,7 @@ private void writeAddFor(MethodReader constructor) {
   }
 
   private void writeBuildMethodStart() {
-    if (beanReader.prototype()) {
+    if (beanReader.registerProvider()) {
       writer.append(CODE_COMMENT_BUILD_PROVIDER, shortName).eol();
     } else {
       writer.append(CODE_COMMENT_BUILD, shortName).eol();
@@ -215,20 +215,20 @@ private void writeCreateBean(MethodReader constructor) {
   }
 
   private void writeExtraInjection() {
-    if (!beanReader.prototype()) {
+    if (!beanReader.registerProvider()) {
       writer.indent("      ").append("builder.addInjector(b -> {").eol();
       writer.indent("      ").append("  // field and method injection").eol();
     }
     injectFields();
     injectMethods();
-    if (!beanReader.prototype()) {
+    if (!beanReader.registerProvider()) {
       writer.indent("      });").eol();
     }
   }
 
   private void injectFields() {
-    String bean = beanReader.prototype() ? "bean" : "$bean";
-    String builder = beanReader.prototype() ? "builder" : "b";
+    String bean = beanReader.registerProvider() ? "bean" : "$bean";
+    String builder = beanReader.registerProvider() ? "builder" : "b";
     for (FieldReader fieldReader : beanReader.injectFields()) {
       String fieldName = fieldReader.fieldName();
       String getDependency = fieldReader.builderGetDependency(builder);
@@ -238,8 +238,8 @@ private void injectFields() {
 
   private void injectMethods() {
     final var needsTry = beanReader.needsTryForMethodInjection();
-    final var bean = beanReader.prototype() ? "bean" : "$bean";
-    final var builder = beanReader.prototype() ? "builder" : "b";
+    final var bean = beanReader.registerProvider() ? "bean" : "$bean";
+    final var builder = beanReader.registerProvider() ? "builder" : "b";
     if (needsTry) {
       writer.indent("        try {").eol();
     }

diff --git a/inject-generator/src/main/java/io/avaje/inject/generator/package-info.java b/inject-generator/src/main/java/io/avaje/inject/generator/package-info.java
@@ -1,31 +1,32 @@
+@GeneratePrism(AOPFallback.class)
+@GeneratePrism(Aspect.class)
+@GeneratePrism(value = Aspect.Import.class, name = "AspectImportPrism")
 @GeneratePrism(Assisted.class)
 @GeneratePrism(AssistFactory.class)
-@GeneratePrism(InjectModule.class)
-@GeneratePrism(Factory.class)
-@GeneratePrism(Singleton.class)
+@GeneratePrism(Bean.class)
 @GeneratePrism(Component.class)
 @GeneratePrism(Component.Import.class)
-@GeneratePrism(Prototype.class)
-@GeneratePrism(Scope.class)
-@GeneratePrism(Qualifier.class)
-@GeneratePrism(Named.class)
+@GeneratePrism(DependencyMeta.class)
+@GeneratePrism(Factory.class)
+@GeneratePrism(Generated.class)
 @GeneratePrism(Inject.class)
-@GeneratePrism(AOPFallback.class)
-@GeneratePrism(Aspect.class)
-@GeneratePrism(value = Aspect.Import.class, name = "AspectImportPrism")
+@GeneratePrism(InjectModule.class)
+@GeneratePrism(Lazy.class)
+@GeneratePrism(Named.class)
+@GeneratePrism(PreDestroy.class)
 @GeneratePrism(Primary.class)
-@GeneratePrism(Secondary.class)
+@GeneratePrism(Profile.class)
+@GeneratePrism(Prototype.class)
 @GeneratePrism(Proxy.class)
-@GeneratePrism(PreDestroy.class)
-@GeneratePrism(DependencyMeta.class)
-@GeneratePrism(Bean.class)
 @GeneratePrism(QualifiedMap.class)
-@GeneratePrism(Generated.class)
+@GeneratePrism(Qualifier.class)
 @GeneratePrism(RequiresBean.class)
 @GeneratePrism(RequiresProperty.class)
 @GeneratePrism(value = RequiresBean.Container.class, name = "RequiresBeanContainerPrism")
 @GeneratePrism(value = RequiresProperty.Container.class, name = "RequiresPropertyContainerPrism")
-@GeneratePrism(Profile.class)
+@GeneratePrism(Singleton.class)
+@GeneratePrism(Scope.class)
+@GeneratePrism(Secondary.class)
 package io.avaje.inject.generator;
 
 import io.avaje.inject.*;

diff --git a/inject-generator/src/test/java/io/avaje/inject/generator/models/valid/lazy/LazyBean.java b/inject-generator/src/test/java/io/avaje/inject/generator/models/valid/lazy/LazyBean.java
@@ -0,0 +1,12 @@
+package io.avaje.inject.generator.models.valid.lazy;
+
+import io.avaje.inject.Lazy;
+import jakarta.inject.Inject;
+import jakarta.inject.Provider;
+import jakarta.inject.Singleton;
+
+@Lazy
+@Singleton
+public class LazyBean {
+  @Inject Provider<Integer> intProvider;
+}
diff --git a/inject-generator/src/test/java/io/avaje/inject/generator/models/valid/lazy/LazyFactory.java b/inject-generator/src/test/java/io/avaje/inject/generator/models/valid/lazy/LazyFactory.java
@@ -0,0 +1,15 @@
+package io.avaje.inject.generator.models.valid.lazy;
+
+import io.avaje.inject.Bean;
+import io.avaje.inject.Factory;
+import io.avaje.inject.Lazy;
+
+@Lazy
+@Factory
+public class LazyFactory {
+
+  @Bean
+  Integer lazyInt() {
+    return 0;
+  }
+}
diff --git a/inject/src/main/java/io/avaje/inject/Lazy.java b/inject/src/main/java/io/avaje/inject/Lazy.java
@@ -0,0 +1,11 @@
+package io.avaje.inject;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/** Marks Singleton/Factory method beans to initialize lazily. */
+@Retention(RetentionPolicy.SOURCE)
+@Target({ElementType.METHOD, ElementType.TYPE})
+public @interface Lazy {}
diff --git a/inject/src/main/java/io/avaje/inject/spi/Builder.java b/inject/src/main/java/io/avaje/inject/spi/Builder.java
@@ -1,15 +1,16 @@
 package io.avaje.inject.spi;
 
-import io.avaje.inject.BeanScope;
-import jakarta.inject.Provider;
-
 import java.lang.reflect.Type;
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
 import java.util.function.Consumer;
 
+import io.avaje.inject.BeanScope;
+import io.avaje.inject.MemoizedProvider;
+import jakarta.inject.Provider;
+
 /**
  * Mutable builder object used when building a bean scope.
  */
@@ -76,6 +77,29 @@ static Builder newBuilder(Set<String> profiles, PropertyRequiresPlugin plugin, L
    */
   <T> void registerProvider(Provider<T> provider);
 
+  /** Register a lazy provider into the context. */
+  default <T> void registerLazy(Provider<T> original) {
+    registerProvider(
+        new Provider<T>() {
+          Provider<T> delegate = this::firstTime;
+          boolean initialized;
+
+          @Override
+          public T get() {
+            return delegate.get();
+          }
+
+          private synchronized T firstTime() {
+            if (!initialized) {
+              T value = original.get();
+              delegate = () -> value;
+              initialized = true;
+            }
+            return delegate.get();
+          }
+        });
+  }
+
   /**
    * Register the bean instance into the context.
    *