Make annotation transformer and object serializer pluggable

Author: Jan Zyka

src/main/java/org/audit4j/core/AnnotationTransformer.java

@@ -24,12 +24,12 @@
 /**
  * Interface for different annotation transformer implementations. This can be
  * used to transform annotation information in to simple audit event.
- * 
+ *
  * @author <a href="mailto:[email protected]">Janith Bandara</a>
  * 
  * @since 2.4.1
  */
-public interface AnnotationTransformer {
+public interface AnnotationTransformer<T extends AuditEvent> {
 
 	/**
 	 * Transform to event.
@@ -38,5 +38,5 @@ public interface AnnotationTransformer {
 	 *            input Annotation AuditEvent
 	 * @return transform audit event
 	 */
-	AuditEvent transformToEvent(AnnotationAuditEvent annotationEvent);
+	T transformToEvent(AnnotationAuditEvent annotationEvent);
 }

src/main/java/org/audit4j/core/Configuration.java

@@ -63,7 +63,12 @@ public class Configuration implements Serializable {
 
     /** The jmx configurations. */
     private JMXConfig jmx;
-    
+
+    /**
+     * Annotation transformer to be used
+     */
+    private AnnotationTransformer annotationTransformer;
+
     /** Return new static instance. 
      * 
      * @since 2.3.1
@@ -293,4 +298,21 @@ public JMXConfig getJmx() {
     public void setJmx(JMXConfig jmx) {
         this.jmx = jmx;
     }
+
+    /**
+     * Gets the annotation transformer to use when converting {@code AnnotationAuditEvent}. Allows to inject custom
+     * conversion logic and custom output type.
+     *
+     * @return the annotation transformer
+     */
+    public AnnotationTransformer getAnnotationTransformer() {
+        return annotationTransformer;
+    }
+
+    /**
+     * Sets annotation transformer to use.
+     */
+    public void setAnnotationTransformer(AnnotationTransformer annotationTransformer) {
+        this.annotationTransformer = annotationTransformer;
+    }
 }

src/main/java/org/audit4j/core/Context.java

@@ -161,15 +161,12 @@ final static void init() {
 			initLayout();
 
 			// Initialize annotation transformer.
-			DefaultAnnotationTransformer defaultAnnotationTransformer = new DefaultAnnotationTransformer();
-			ObjectSerializerCommand serializerCommand = (ObjectSerializerCommand) PreConfigurationContext
-					.getCommandByName("-objectSerializer");
-			if (serializerCommand.getSerializer() == null) {
-				defaultAnnotationTransformer.setSerializer(new ObjectToFieldsSerializer());
+
+			if (conf.getAnnotationTransformer() == null) {
+				annotationTransformer = getDefaultAnnotationTransformer();
 			} else {
-				defaultAnnotationTransformer.setSerializer(serializerCommand.getSerializer());
+				annotationTransformer = conf.getAnnotationTransformer();
 			}
-			annotationTransformer = defaultAnnotationTransformer;
 
 			// Initialize IO streams.
 			initStreams();
@@ -414,6 +411,24 @@ private static void initStreams() {
 		Log.info("Audit Streams Initialized.");
 	}
 
+	/**
+	 * Initializes and returns the default annotation transformer.
+	 *
+	 * @return default annotation transformer
+     */
+	private static AnnotationTransformer<AuditEvent> getDefaultAnnotationTransformer() {
+		DefaultAnnotationTransformer defaultAnnotationTransformer = new DefaultAnnotationTransformer();
+		ObjectSerializerCommand serializerCommand = (ObjectSerializerCommand) PreConfigurationContext
+				.getCommandByName("-objectSerializer");
+		if (serializerCommand.getSerializer() == null) {
+			defaultAnnotationTransformer.setSerializer(new ObjectToFieldsSerializer());
+		} else {
+			defaultAnnotationTransformer.setSerializer(serializerCommand.getSerializer());
+		}
+
+		return defaultAnnotationTransformer;
+	}
+
 	/**
 	 * Sets the config.
 	 * 

src/main/java/org/audit4j/core/DefaultAnnotationTransformer.java

@@ -39,12 +39,20 @@
  * 
  * @since 2.0.0
  */
-public class DefaultAnnotationTransformer implements AnnotationTransformer {
+public class DefaultAnnotationTransformer implements AnnotationTransformer<AuditEvent> {
 
 	private final static String ACTION = "action";
 
 	// Default Fields serializer
-	private ObjectSerializer serializer = new ObjectToFieldsSerializer();
+	private ObjectSerializer serializer;
+
+	public DefaultAnnotationTransformer() {
+		this.serializer = new ObjectToFieldsSerializer();
+	}
+
+	public DefaultAnnotationTransformer(ObjectSerializer objectSerializer) {
+		this.serializer = objectSerializer;
+	}
 
 	/**
 	 * Transform annotation informations to Audit Event object.

src/main/java/org/audit4j/core/dto/AnnotationAuditEvent.java

@@ -41,6 +41,9 @@ public class AnnotationAuditEvent extends AuditEvent {
     /** The args. */
     Object[] args;
 
+    /** The return of hte method, may be null */
+    private Object methodCallResult;
+
     /**
      * Instantiates a new annotation audit event.
      */
@@ -65,6 +68,11 @@ public AnnotationAuditEvent(Class<?> clazz, Method method, Object[] args) {
         this.args = args;
     }
 
+    public AnnotationAuditEvent(Class<?> clazz, Method method, Object[] args, Object methodCallResult) {
+        this(clazz, method, args);
+        this.methodCallResult = methodCallResult;
+    }
+
     /**
      * Gets the clazz.
      * 
@@ -122,4 +130,13 @@ public void setArgs(Object[] args) {
         this.args = args;
     }
 
+    /**
+     * Gets the return object of method call. May be {@code null} in the case the method was {@code void} or in the case
+     * the @Before aspect was used and therefore no return type was available.
+     *
+     * @return the {@code Object} returned by the audited method, if captured
+     */
+    public Object getMethodCallResult() {
+        return methodCallResult;
+    }
 }

src/main/java/org/audit4j/core/handler/Handler.java

@@ -31,7 +31,7 @@
  * 
  * @author Janith Bandara
  */
-public abstract class Handler implements Initializable, Serializable {
+public abstract class Handler<T extends AuditEvent> implements Initializable, Serializable {
 
     /** The Constant serialVersionUID. */
     private static final long serialVersionUID = -8636058037478806582L;
@@ -40,7 +40,7 @@ public abstract class Handler implements Initializable, Serializable {
     private String query;
 
     /** The audit event. */
-    private AuditEvent auditEvent;
+    private T auditEvent;
 
     /** The properties. */
     private Map<String, String> properties;
@@ -76,7 +76,7 @@ public void setQuery(final String query) {
      * 
      * @return the audit event
      */
-    public AuditEvent getAuditEvent() {
+    public T getAuditEvent() {
         return auditEvent;
     }
 
@@ -86,7 +86,7 @@ public AuditEvent getAuditEvent() {
      * @param auditEvent
      *            the new audit event
      */
-    public void setAuditEvent(final AuditEvent auditEvent) {
+    public void setAuditEvent(final T auditEvent) {
         this.auditEvent = auditEvent;
     }