Fixed ALF-9515: Activiti can no longer be disabled

Both Activiti and JBPM can now be "disabled" using the properties "system.workflow.engine.activiti.enabled" and "system.workflow.engine.jbpm.enabled", respectively. However, disabling JBPM is NOT recommended as several parts of the system are reliant on it. Furthermore, "disabled" just means the process definitions are not deployed and the engine is not registered with the WorkflowService, all DB tables etc. are still present. This means the engines can be disabled and re-enabled at will.

Also added back-end support for ALF-9392: More workflow metrics are required on the Workflow Console Admin Tool. An MBean is now available in Enterprise mode that provides the number of tasks, workflow definitions deployed and workflow instances in the system.

Added ENGINE_ID constant to JBPMEngine and globally replaced use of "jbpm" hard coded string.

git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/HEAD/root@29326 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261

source/java/org/alfresco/service/cmr/workflow/WorkflowAdminService.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2005-2011 Alfresco Software Limited.
+ *
+ * This file is part of Alfresco
+ *
+ * Alfresco is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Alfresco is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with Alfresco. If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.alfresco.service.cmr.workflow;
+
+/**
+ * Client facing API for providing administration information about the
+ * {@link WorkflowService}.
+ *
+ * @author Gavin Cornwell
+ * @since 4.0
+ */
+public interface WorkflowAdminService
+{
+    /**
+     * Determines whether the engine with the given id is enabled.
+     * 
+     * @param engineId The id of a workflow engine
+     * @return true if the engine id is valid and is enabled
+     */
+    public boolean isEngineEnabled(String engineId);
+}