fix: show @scheduled methods as implicitly used

Signed-off-by: Fred Bricon <[email protected]>

src/main/java/com/redhat/devtools/intellij/quarkus/QuarkusConstants.java

@@ -71,6 +71,8 @@ public class QuarkusConstants {
 
     public static final String QUARKUS_DEPLOYMENT_BUILDSTEP_ANNOTATION = "io.quarkus.deployment.annotations.BuildStep";
 
+    public static final String QUARKUS_SCHEDULED_ANNOTATION = "io.quarkus.scheduler.Scheduled";
+
     public static final String QUARKUS_CORE_PREFIX = "io.quarkus:quarkus-core:";
     public static final String QUARKUS_PREFIX = "quarkus";
     public static final String QUARKUS_JAVADOC_PROPERTIES_FILE = "quarkus-javadoc.properties";

src/main/java/com/redhat/devtools/intellij/quarkus/psi/internal/ScheduledImplicitUsageProvider.java

@@ -0,0 +1,66 @@
+/*******************************************************************************
+ * Copyright (c) 2023 Red Hat Inc. and others.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
+ * which is available at https://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
+ *
+ * Contributors:
+ *     Red Hat Inc. - initial API and implementation
+ *******************************************************************************/
+package com.redhat.devtools.intellij.quarkus.psi.internal;
+
+import com.intellij.codeInsight.daemon.ImplicitUsageProvider;
+import com.intellij.psi.PsiClass;
+import com.intellij.psi.PsiElement;
+import com.intellij.psi.PsiMethod;
+import com.redhat.devtools.intellij.lsp4mp4ij.psi.core.utils.AnnotationUtils;
+import com.redhat.devtools.intellij.lsp4mp4ij.psi.internal.metrics.MicroProfileMetricsConstants;
+import org.jetbrains.annotations.NotNull;
+
+import static com.redhat.devtools.intellij.quarkus.QuarkusConstants.QUARKUS_DEPLOYMENT_BUILDSTEP_ANNOTATION;
+import static com.redhat.devtools.intellij.quarkus.QuarkusConstants.QUARKUS_SCHEDULED_ANNOTATION;
+
+/**
+ * Automatically declares as used, methods annotated with {@link io.quarkus.scheduler.Scheduled} annotations, on <code>@ApplicationScoped</code>-annotated classes.
+ * <p>
+ * {@code
+ *     @Scheduled(cron="0 15 10 * * ?")
+ *     void cronJob(ScheduledExecution execution) {
+ *         counter.incrementAndGet();
+ *         System.out.println(execution.getScheduledFireTime());
+ *     }
+ * }
+ * </p>
+ */
+public class ScheduledImplicitUsageProvider implements ImplicitUsageProvider {
+
+    @Override
+    public boolean isImplicitUsage(@NotNull PsiElement element) {
+        return isImplicitRead(element) || isImplicitWrite(element);
+    }
+
+    @Override
+    public boolean isImplicitRead(@NotNull PsiElement element) {
+        if (!(element instanceof PsiMethod)) {
+            return false;
+        }
+        PsiMethod method = (PsiMethod) element;
+        return !method.isConstructor() &&
+                AnnotationUtils.hasAnyAnnotation(element, QUARKUS_SCHEDULED_ANNOTATION) &&
+                isClassApplicationScoped(method.getContainingClass());
+    }
+
+    private boolean isClassApplicationScoped(PsiClass containingClass) {
+        return (containingClass != null) && AnnotationUtils.hasAnyAnnotation(containingClass, MicroProfileMetricsConstants.APPLICATION_SCOPED_JAKARTA_ANNOTATION,
+                MicroProfileMetricsConstants.APPLICATION_SCOPED_JAVAX_ANNOTATION);
+    }
+
+    @Override
+    public boolean isImplicitWrite(@NotNull PsiElement element) {
+        return false;
+    }
+}

src/main/resources/META-INF/lsp4ij-quarkus.xml

@@ -49,6 +49,7 @@
 
     <implicitUsageProvider implementation="com.redhat.devtools.intellij.lsp4mp4ij.psi.core.JavaEEImplicitUsageProvider"/>
     <implicitUsageProvider implementation="com.redhat.devtools.intellij.quarkus.psi.internal.QuarkusBuildImplicitUsageProvider"/>
+    <implicitUsageProvider implementation="com.redhat.devtools.intellij.quarkus.psi.internal.ScheduledImplicitUsageProvider"/>
     <implicitUsageProvider implementation="com.redhat.microprofile.psi.internal.quarkus.route.java.ReactiveRouteImplicitUsageProvider"/>
 
     <!-- Quarkus -->