[core] Add getUniverseContext within ExternalContextAccess.

close #773

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

docs/io.sarl.docs.markdown/src/main/documentation/reference/bic/ExternalContextAccess.md

@@ -11,6 +11,7 @@ top-right context in the figure above.
 		      documented --> 
 		[:Fact:]{typeof(io.sarl.core.[:externalcontextaccess!]).shouldHaveMethods(
 			"[:getcontext](getContext)(java.util.UUID) : io.sarl.lang.core.AgentContext",
+			"[:getuniversecontext](getUniverseContext) : io.sarl.lang.core.AgentContext",
 			"[:getallcontexts](getAllContexts) : io.sarl.lang.util.SynchronizedIterable",
 			"[:join](join)(java.util.UUID, java.util.UUID) : boolean",
 			"[:leave](leave)(java.util.UUID) : boolean",
@@ -60,6 +61,24 @@ may use its `[:getParentID](getParentID)` for accessing the context in which it
 		[:End:]
 
 
+## Retrieving the Universe Context
+
+In all the SARL application, a default context exists. It's name is the Universe context.
+It is fully managed by the SARL run-time environment.
+For retrieving this particular context, this built-in capacity provides the following function:
+
+		[:Success:]
+			package io.sarl.docs.reference.bic
+			import io.sarl.lang.core.AgentContext
+			import java.util.UUID
+			interface Tmp {
+			[:On]
+				def [:getuniversecontext!]() : AgentContext
+			[:Off]
+			}
+		[:End:]
+
+
 ## Retrieving the Contexts of an Agent
 
 The following function enables an agent to retrieve all the contexts in which it is involved:

main/apiplugins/io.sarl.core/src/io/sarl/core/bic.sarl

@@ -65,6 +65,17 @@ capacity ExternalContextAccess {
 	@Pure
 	def getContext(contextID : UUID): AgentContext
 
+	/**
+	 * Replies the AgentContext that is the root of all the contexts.
+	 * Usually, the Universe context is managed by the SARL run-time environment.
+	 * The agent may be a member of this context, or not.
+	 *
+	 * @return the context that is at the root of all the contexts.
+	 * @since 0.7
+	 */
+	@Pure
+	def getUniverseContext(): AgentContext
+
     /**
 	 * Joins a new parent context (a new super holon).
 	 * <p>

sre/io.janusproject/io.janusproject.plugin/src/io/janusproject/kernel/bic/ExternalContextAccessSkill.java

@@ -151,6 +151,11 @@ public AgentContext getContext(UUID contextID) {
 		return this.contextRepository.getContext(contextID);
 	}
 
+	@Override
+	public AgentContext getUniverseContext() {
+		return this.contextRepository.getUniverseContext();
+	}
+
 	@Override
 	public boolean join(UUID futureContext, UUID futureContextDefaultSpaceID) {
 		assert futureContext != null;

sre/io.janusproject/io.janusproject.plugin/src/io/janusproject/kernel/services/jdk/contextspace/StandardContextSpaceService.java

@@ -98,6 +98,8 @@ public class StandardContextSpaceService extends AbstractDependentService implem
 	 */
 	private ContextDMapListener dmapListener;
 
+	private AgentContext janusContext;
+
 	/**
 	 * Log service.
 	 */
@@ -110,6 +112,17 @@ public StandardContextSpaceService() {
 		//
 	}
 
+	/**
+	 * Change the Janus context of the kernel.
+	 *
+	 * @param janusContext the new janus kernel. It must be never <code>null</code>.
+	 */
+	@Inject
+	void setJanusContext(@io.janusproject.kernel.annotations.Kernel AgentContext janusContext) {
+		assert janusContext != null;
+		this.janusContext = janusContext;
+	}
+
 	@Override
 	public final Class<? extends Service> getServiceType() {
 		return ContextSpaceService.class;
@@ -279,6 +292,11 @@ public AgentContext getContext(UUID contextID) {
 		}
 	}
 
+	@Override
+	public AgentContext getUniverseContext() {
+		return this.janusContext;
+	}
+
 	@Override
 	public void addContextRepositoryListener(ContextRepositoryListener listener) {
 		this.listeners.add(ContextRepositoryListener.class, listener);

sre/io.janusproject/io.janusproject.plugin/src/io/janusproject/services/contextspace/ContextSpaceService.java

@@ -126,6 +126,13 @@ public interface ContextSpaceService extends DependentService {
 	 */
 	AgentContext getContext(UUID contextID);
 
+	/**
+	 * Returns the {@link AgentContext} that is the root of all the contexts.
+	 *
+	 * @return the root {@link AgentContext}.
+	 */
+	AgentContext getUniverseContext();
+
 	/**
 	 * Add a listener on the context repository events.
 	 *

tests/io.sarl.core.tests/src/test/java/io/sarl/core/tests/ExternalContextAccessTest.java

@@ -48,7 +48,7 @@ public void setUp() {
 	 */
 	@Test
 	public void memberCount() {
-		assertEquals(9, this.type.getDeclaredMethods().length);
+		assertEquals(10, this.type.getDeclaredMethods().length);
 	}
 
 	/**
@@ -65,6 +65,13 @@ public void getContext() {
 		assertMethod("getContext", AgentContext.class, UUID.class); //$NON-NLS-1$
 	}
 
+	/**
+	 */
+	@Test
+	public void getUniverseContext() {
+		assertMethod("getUniverseContext", AgentContext.class); //$NON-NLS-1$
+	}
+
 	/**
 	 */
 	@Test