[lang][core] Add observer on the SRE start and stop.

Signed-off-by: Stéphane Galland <galland@arakhne.org>

main/coreplugins/io.sarl.lang.core/src/io/sarl/bootstrap/SRE.java

@@ -238,6 +238,16 @@ public void shutdown(boolean blocking, int timeout) throws InterruptedException
 			throw new UnsupportedOperationException();
 		}
 
+		@Override
+		public void addSREListener(SREListener listener) {
+			//
+		}
+
+		@Override
+		public void removeSREListener(SREListener listener) {
+			//
+		}
+
 	}
 
 }

main/coreplugins/io.sarl.lang.core/src/io/sarl/bootstrap/SREBootstrap.java

@@ -321,4 +321,20 @@ default void shutdown(int timeout) throws InterruptedException {
 	@Pure
 	<T> T getService(Class<T> serviceType);
 
+	/**
+	 * Add an observer on the SRE.
+	 *
+	 * @param listener the observer to add.
+	 * @since 0.11
+	 */
+	void addSREListener(SREListener listener);
+
+	/**
+	 * Remove the given observer on the SRE.
+	 *
+	 * @param listener the observer to remove.
+	 * @since 0.11
+	 */
+	void removeSREListener(SREListener listener);
+
 }

main/coreplugins/io.sarl.lang.core/src/io/sarl/bootstrap/SREListener.java

@@ -0,0 +1,51 @@
+/*
+ * $Id$
+ *
+ * SARL is an general-purpose agent programming language.
+ * More details on http://www.sarl.io
+ *
+ * Copyright (C) 2014-2020 the original authors or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.sarl.bootstrap;
+
+import java.util.EventListener;
+
+/**
+ * Observer on SRE events.
+ *
+ * <p>This observer will be notified depending on the the implementation of the SRE.
+ *
+ * @author $Author: sgalland$
+ * @version $FullVersion$
+ * @mavengroupid $GroupId$
+ * @mavenartifactid $ArtifactId$
+ * @since 0.11
+ */
+public interface SREListener extends EventListener {
+
+	/** Invoked when the SRE is started.
+	 *
+	 * @param sre the started SRE.
+	 */
+	void sreStarted(SREBootstrap sre);
+
+	/** Invoked when the SRE is stopped.
+	 *
+	 * @param sre the stopped SRE.
+	 */
+	void sreStopped(SREBootstrap sre);
+
+}

sre/io.janusproject/io.janusproject.plugin/src/main/sarl/io/sarl/sre/boot/SreMain.sarl

@@ -33,6 +33,7 @@ import io.bootique.help.HelpOptions
 import io.bootique.meta.application.ApplicationMetadata
 import io.sarl.bootstrap.SRE
 import io.sarl.bootstrap.SREBootstrap
+import io.sarl.bootstrap.SREListener
 import io.sarl.lang.core.Agent
 import io.sarl.lang.core.AgentContext
 import io.sarl.sre.Kernel
@@ -48,6 +49,7 @@ import org.apache.log4j.Logger
 import org.arakhne.afc.bootique.log4j.configs.Level
 import org.arakhne.afc.bootique.log4j.configs.Log4jIntegrationConfig
 import org.arakhne.afc.bootique.variables.VariableNames
+import org.arakhne.afc.util.ListenerCollection
 import org.eclipse.xtend.lib.annotations.Accessors
 
 import static io.sarl.bootstrap.SRE.*
@@ -74,6 +76,8 @@ class SreMain implements SREBootstrap {
 	var userDefinedContextId : UUID
 
 	var userDefinedSpaceId : UUID
+
+	val listeners = new ListenerCollection<SREListener>
 
 	/** Set the Bootique runtime instance.
 	 *
@@ -243,9 +247,11 @@ class SreMain implements SREBootstrap {
 			val listener : KernelAgentLifecycleListener = [
 				this.kernel = null
 				this.runtime = null
+				fireSREStopped
 			]
 			k.getService(typeof(LifecycleService)).addKernelAgentLifecycleListener(listener)
 			this.kernel = k
+			fireSREStarted
 		}
 		// Force the bootstrap to be this object
 		SRE::bootstrap = this
@@ -347,4 +353,46 @@ class SreMain implements SREBootstrap {
 		return null
 	}
 
+	override addSREListener(listener : SREListener) {
+		if (listener !== null) {
+			this.listeners.add(typeof(SREListener), listener)
+		}
+	}
+
+	override removeSREListener(listener : SREListener) {
+		if (listener !== null) {
+			this.listeners.remove(typeof(SREListener), listener)
+		}
+	}
+
+	/** Notifies the observers that the SRE has been started.
+	 *
+	 * @since 0.11
+	 */
+	protected def fireSREStarted {
+		val observers = this.listeners.getListeners(typeof(SREListener))
+		for (observer : observers) {
+			try {
+				observer.sreStarted(this)
+			} catch (exception : Throwable) {
+				getKernelLogger.log(java.util.logging.Level::SEVERE, exception.localizedMessage, exception)
+			}
+		}
+	}
+
+	/** Notifies the observers that the SRE has been stopped.
+	 * 
+	 * @since 0.11
+	 */
+	protected def fireSREStopped {
+		val observers = this.listeners.getListeners(typeof(SREListener))
+		for (observer : observers) {
+			try {
+				observer.sreStopped(this)
+			} catch (exception : Throwable) {
+				getKernelLogger.log(java.util.logging.Level::SEVERE, exception.localizedMessage, exception)
+			}
+		}
+	}
+
 }

sre/io.janusproject/io.janusproject.plugin/src/main/sarl/io/sarl/sre/services/lifecycle/AgentLife.sarl

@@ -36,7 +36,6 @@ import io.sarl.lang.core.SpaceID
 import io.sarl.sre.capacities.InternalEventBusCapacity
 import io.sarl.sre.services.context.Context
 import io.sarl.sre.services.logging.LoggingService
-import java.lang.ref.WeakReference
 import java.util.List
 import java.util.Map
 import java.util.UUID

sre/io.janusproject/io.janusproject.tests/src/test/sarl/io/sarl/sre/tests/runtime/boot/bootstrap/BootstrapTest.sarl

@@ -21,6 +21,8 @@
 
 package io.sarl.sre.tests.runtime.boot.bootstrap
 
+import io.sarl.bootstrap.SREBootstrap
+import io.sarl.bootstrap.SREListener
 import io.sarl.sre.boot.configs.subconfigs.BootConfig
 import io.sarl.sre.boot.configs.subconfigs.RootContextType
 import io.sarl.sre.test.framework.context.SreRunContext
@@ -39,9 +41,12 @@ import org.junit.jupiter.api.Tag
 import org.junit.jupiter.api.Test
 import org.junit.jupiter.api.^extension.ExtendWith
 
-import static extension org.junit.jupiter.api.Assertions.*
 import static io.sarl.sre.test.framework.Constants.*
 
+import static extension org.junit.jupiter.api.Assertions.*
+import static extension org.mockito.ArgumentCaptor.*
+import static extension org.mockito.Mockito.*
+
 /**
  * @author $Author: sgalland$
  * @version $FullVersion$
@@ -118,4 +123,25 @@ class BootstrapTest {
 		id.assertEquals(actual)
 	}
 
+	@Test
+	@DisplayName("sreStopped")
+	def sreStartedStopped(extension rc : SreRunContext) {
+		val observer = typeof(SREListener).mock
+
+		val kern = setupTheSreKernel(null, null)
+		kern.addSREListener(observer)
+
+		val id = UUID::randomUUID
+		kern.startAgentWithID(typeof(TestIdAgent0), id, agentInitializationParameters)
+		waitForTheKernel(SHORT_TIMEOUT)
+
+		var arg = typeof(SREBootstrap).forClass
+
+		// Never called because the event is fired before setupTheSreKernel returns
+		observer.verify(never).sreStarted(any)
+
+		observer.verify(1.times).sreStopped(arg.capture)
+		kern.assertSame(arg.value)
+	}
+
 }