Refactoring audit subsystem to clean-up and eliminate back-dependency from core to CLI; still needs additional work.

Change-Id: I93c04c94f27b7b89c582b359eebe125458a573a7
diff --git a/core/net/src/main/java/org/onosproject/audit/impl/AuditManager.java b/core/net/src/main/java/org/onosproject/audit/impl/AuditManager.java
new file mode 100644
index 0000000..a871f3c
--- /dev/null
+++ b/core/net/src/main/java/org/onosproject/audit/impl/AuditManager.java
@@ -0,0 +1,99 @@
+/*
+ * Copyright 2016-present Open Networking Foundation
+ *
+ * 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 org.onosproject.audit.impl;
+
+import org.onosproject.cfg.ComponentConfigService;
+import org.onosproject.security.AuditService;
+import org.osgi.service.component.ComponentContext;
+import org.osgi.service.component.annotations.Component;
+import org.osgi.service.component.annotations.Deactivate;
+import org.osgi.service.component.annotations.Modified;
+import org.osgi.service.component.annotations.Activate;
+import org.osgi.service.component.annotations.Reference;
+import org.osgi.service.component.annotations.ReferenceCardinality;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Dictionary;
+
+import static org.onlab.util.Tools.get;
+import static org.onosproject.net.OsgiPropertyConstants.AUDIT_LOGGER;
+import static org.onosproject.net.OsgiPropertyConstants.AUDIT_LOGGER_DEFAULT;
+import static org.onosproject.net.OsgiPropertyConstants.AUDIT_ENABLED;
+import static org.onosproject.net.OsgiPropertyConstants.AUDIT_ENABLED_DEFAULT;
+
+/**
+ * Component to manage audit logging.
+ */
+@Component(
+        immediate = true,
+        service = { AuditService.class },
+        property = {
+                AUDIT_ENABLED + ":Boolean=" + AUDIT_ENABLED_DEFAULT,
+                AUDIT_LOGGER + "=" + AUDIT_LOGGER_DEFAULT,
+        })
+public class AuditManager implements AuditService {
+
+    private final Logger log = LoggerFactory.getLogger(getClass());
+
+    private Logger auditLog = log;
+
+    /** Specifies whether or not audit logging is enabled. */
+    private boolean auditEnabled = AUDIT_ENABLED_DEFAULT;
+
+    /** Name of the audit logger. */
+    private String auditFile = AUDIT_LOGGER_DEFAULT;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY)
+    protected ComponentConfigService cfgService;
+
+    @Activate
+    protected void activate(ComponentContext ctx) {
+        cfgService.registerProperties(getClass());
+        modified(ctx);
+        log.info("Started");
+    }
+
+    @Deactivate
+    protected void deactivate(ComponentContext ctx) {
+        log.info("Stopped");
+    }
+
+    @Modified
+    protected void modified(ComponentContext ctx) {
+        Dictionary<?, ?> properties = ctx.getProperties();
+        if (properties != null) {
+            auditEnabled = Boolean.parseBoolean(get(properties, AUDIT_ENABLED));
+            auditFile = get(properties, AUDIT_LOGGER);
+            auditLog = LoggerFactory.getLogger(auditFile);
+            log.info("Reconfigured; auditEnabled={}; auditFile={}", auditEnabled, auditFile);
+        }
+    }
+
+    @Override
+    public boolean isAuditing() {
+        return auditEnabled;
+    }
+
+    @Override
+    public void logUserAction(String user, String action) {
+        if (auditEnabled) {
+            auditLog.info("user={}; action={}", user, action);
+        }
+    }
+
+}