Add io.avaje.inject @PostConstruct/@PreDestroy annotations (#71)

Author: rbygrave

inject-test/src/test/java/org/example/coffee/factory/Configuration.java

@@ -2,10 +2,10 @@
 
 import io.avaje.inject.Bean;
 import io.avaje.inject.Factory;
+import io.avaje.inject.PostConstruct;
+import io.avaje.inject.PreDestroy;
 import org.example.coffee.CoffeeMaker;
 
-import javax.annotation.PostConstruct;
-import javax.annotation.PreDestroy;
 import javax.inject.Inject;
 
 /**
@@ -41,7 +41,6 @@ BFact buildB(AFact afact, CoffeeMaker maker) {
     return new BFact(afact, maker);
   }
 
-
   @PostConstruct
   void initFactory() {
     countInit++;

inject/src/main/java/io/avaje/inject/PostConstruct.java

@@ -0,0 +1,32 @@
+package io.avaje.inject;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+
+/**
+ * The <code>PostConstruct</code> annotation is used on a method that needs to be executed
+ * after dependency injection is done to perform any initialization.
+ * <p>
+ * Note that we can equally use any <code>PostConstruct</code> annotation - so we can use
+ * the one from <code>javax.annotation</code>, <code>jakarta.annotation</code> or this one.
+ * </p>
+ * <p>
+ * Only one method in a given class can be annotated with this annotation.
+ * <p>
+ * The method on which the <code>PostConstruct</code> annotation is applied must fulfill
+ * the following criteria:
+ * <ul>
+ * <li>The method must not have any parameters.</li>
+ * <li>The method may be public, protected or package private.</li>
+ * <li>The method must not be static.</li>
+ * </ul>
+ */
+@Documented
+@Retention(RUNTIME)
+@Target(METHOD)
+public @interface PostConstruct {
+}

inject/src/main/java/io/avaje/inject/PreDestroy.java

@@ -0,0 +1,32 @@
+package io.avaje.inject;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+
+/**
+ * The <code>PreDestroy</code> annotation is used on a method as a callback notification
+ * to signal that the instance is in the process of being removed by the container.
+ * <p>
+ * Note that we can equally use any <code>PreDestroy</code> annotation - so we can use
+ * the one from <code>javax.annotation</code>, <code>jakarta.annotation</code> or this one.
+ * <p>
+ * The method annotated with <code>PreDestroy</code> is typically used to release resources
+ * that it has been holding.
+ * <p>
+ * The method on which the <code>PreDestroy</code> annotation is applied must fulfill the
+ * following criteria:
+ * <ul>
+ * <li>The method must not have any parameters.</li>
+ * <li>The method may be public, protected or package private.</li>
+ * <li>The method must not be static.</li>
+ * </ul>
+ */
+@Documented
+@Retention(RUNTIME)
+@Target(METHOD)
+public @interface PreDestroy {
+}