feat: Apply different fields to call, return, sql, etc

return events don't duplicate the function call fields.
http_server_request and sql_query don't need function call fields either.

Delivers #50
Delivers #44

src/main/java/com/appland/appmap/output/v1/Event.java

@@ -3,7 +3,6 @@
 import com.alibaba.fastjson.annotation.JSONField;
 import javassist.CtBehavior;
 
-import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
 import java.util.ArrayList;
 
@@ -66,37 +65,38 @@ private synchronized Integer issueId() {
   }
 
   /**
-   * Constructs a blank event and issues a unique ID.
+   * Creates a copy of an existing call event. Does not copy runtime information such as
+   * {@link Parameters} or return value.
+   *
+   * @param master The event to copy information from
    */
-  public Event() {
-    this.setId(issueId());
+  public static Event functionCallEvent(Event master) {
+    Event event = new Event();
+    event.setEvent("call");
+    event.setThreadId(Thread.currentThread().getId());
+    event.setMethodId(master.methodId);
+    event.setDefinedClass(master.definedClass);
+    event.setPath(master.path);
+    event.setLineNumber(master.lineNumber);
+    event.setStatic(master.isStatic);
+    return event;
   }
 
   /**
-   * Creates a copy of an existing event. Does not copy runtime information such as
-   * {@link Parameters} or return value.
-   * @param master The event to copy information from
+   * Creates a return event. All the event properties except for the id are
+   * left to be filled in later.
    */
-  public Event(Event master) {
-    this.setId(issueId())
-        .setMethodId(master.methodId)
-        .setDefinedClass(master.definedClass)
-        .setPath(master.path)
-        .setLineNumber(master.lineNumber)
-        .setStatic(master.isStatic);
+  public static Event functionReturnEvent() {
+    Event event = new Event();
+    event.setEvent("return");
+    return event;
   }
 
   /**
-   * Creates an event from a reflective Method.
-   * @param method Method to gather information from
-   * @param eventType The type of this event ("call", "return", etc.)
+   * Constructs a blank event and issues a unique ID.
    */
-  public Event(Method method, String eventType) {
-    this.setId(issueId())
-        .setMethodId(method.getName())
-        .setDefinedClass(method.getDeclaringClass().getName())
-        .setEvent(eventType)
-        .setThreadId(Thread.currentThread().getId());
+  public Event() {
+    this.setId(issueId());
   }
 
   /**
@@ -303,6 +303,7 @@ public Event setParameters(Parameters parameters) {
    * @see <a href="https://github.com/applandinc/appmap#http-server-request-attributes">GitHub: AppMap - HTTP server request attributes</a>
    */
   public Event setHttpServerRequest(String method, String path, String protocol) {
+    clearFunctionFields();
     this.httpServerRequest = new HttpServerRequest()
         .setMethod(method)
         .setPath(path)
@@ -345,6 +346,7 @@ public Event setHttpServerResponse(Integer status, String mimeType) {
    * @see <a href="https://github.com/applandinc/appmap#http-client-request-attributes">GitHub: AppMap - HTTP client request attributes</a>
    */
   public Event setHttpClientRequest(String method, String path, String protocol) {
+    clearFunctionFields();
     this.httpClientRequest = new HttpClientRequest()
             .setMethod(method)
             .setPath(path)
@@ -374,7 +376,7 @@ public Event setHttpClientResponse(Integer status, String mimeType) {
    */
   public Event addMessageParam(Value val) {
     if (this.message == null) {
-      this.message = new ArrayList<Value>();
+      this.message = new ArrayList<>();
     }
 
     this.message.add(val);
@@ -401,6 +403,7 @@ public Event addMessageParam(String name, Object val) {
    * @see <a href="https://github.com/applandinc/appmap#sql-query-attributes">GitHub: AppMap - SQL query attributes</a>
    */
   public Event setSqlQuery(String databaseType, String sql) {
+    clearFunctionFields();
     this.sqlQuery = new SqlQuery(databaseType, sql);
     return this;
   }
@@ -409,7 +412,6 @@ public Event setSqlQuery(String databaseType, String sql) {
    * Convert all referenced Objects to Strings. This mitigates the risk of null pointer exceptions
    * or reading otherwise invalid state when later serializing this event. This should always be
    * called once an event has been finalized.
-   * @return
    */
   public Event freeze() {
     if (this.parameters != null) {
@@ -434,4 +436,12 @@ public Event freeze() {
 
     return this;
   }
+
+  void clearFunctionFields() {
+    methodId = null;
+    definedClass = null;
+    path = null;
+    lineNumber = null;
+    isStatic = null;
+  }
 }

src/main/java/com/appland/appmap/record/EventTemplateRegistry.java

@@ -16,10 +16,10 @@
  * for performance.
  */
 public class EventTemplateRegistry {
-  private static EventTemplateRegistry instance = new EventTemplateRegistry();
+  private static final EventTemplateRegistry instance = new EventTemplateRegistry();
   private static final Recorder recorder = Recorder.getInstance();
 
-  private ArrayList<Event> eventTemplates = new ArrayList<Event>();
+  private final ArrayList<Event> eventTemplates = new ArrayList<>();
 
   private EventTemplateRegistry() { }
 
@@ -43,7 +43,7 @@ public Integer register(CtBehavior behavior) {
    * have a {@link CodeObject} registered with the global {@link Recorder} instance.
    * @param event The {@link Event} template to be registered
    * @param behavior The behavior used to create the {@link Event} template
-   * @returns The behavior ordinal (an index to the {@link Event} template)
+   * @return The behavior ordinal (an index to the {@link Event} template)
    */
   public synchronized Integer register(Event event, CtBehavior behavior) {
     recorder.registerCodeObject(CodeObject.createTree(behavior));
@@ -68,25 +68,28 @@ public Event getTemplate(Integer templateId) {
   /**
    * Clones an {@link Event} template and sets the {@code event} field.
    * @param templateId The behavior ordinal
-   * @param eventAction The value of the {@code event} field ({@code call}, {@code return}, etc.)
    * @return A copy of the event template with the {@code event} field set
    * @throws UnknownEventException If no template exists for the behavior ordinal given
    */
-  public Event cloneEventTemplate(int templateId, String eventAction)
-      throws UnknownEventException {
-    Event event = null;
+  public Event buildCallEvent(int templateId) {
+    Event eventTemplate = lookupEventTemplate(templateId);
+    Event event = Event.functionCallEvent(eventTemplate);
+    for (Value param : eventTemplate.parameters) {
+      event.addParameter(param);
+    }
+    return event;
+  }
 
-    try {
-      Event eventTemplate = eventTemplates.get(templateId);
-      event = new Event(eventTemplate)
-          .setThreadId(Thread.currentThread().getId())
-          .setEvent(eventAction);
+  /**
+   * Prepares a return event.
+   */
+  public Event buildReturnEvent() {
+    return Event.functionReturnEvent();
+  }
 
-      if (eventAction.equals("call")) {
-        for (Value param : eventTemplate.parameters) {
-          event.addParameter(param);
-        }
-      }
+  Event lookupEventTemplate(int templateId) {
+    try {
+      return eventTemplates.get(templateId);
     } catch (IndexOutOfBoundsException e) {
       final String msg = String.format("unknown template for ordinal %d - have we been loaded by a non-system class loader?", templateId);
 
@@ -97,7 +100,5 @@ public Event cloneEventTemplate(int templateId, String eventAction)
 
       throw new UnknownEventException(msg);
     }
-
-    return event;
   }
 }

src/test/java/com/appland/appmap/record/EventTemplateRegistryTest.java

@@ -37,18 +37,23 @@ public void testRegister() throws Exception {
     }
   }
 
-  @Test
-  public void testCloneEventTemplate() throws UnknownEventException, Exception {
-    CtClass myClass = new ClassBuilder("testCloneEventTemplateClass")
+  CtClass buildCloneableEventTemplate() throws Exception {
+    return new ClassBuilder("testCloneEventTemplateClass")
         .beginMethod()
-          .setName("registeredMethod")
+        .setName("registeredMethod")
         .endMethod()
         .ctClass();
+  }
 
-    Integer index = registry.register(myClass.getDeclaredMethod("registeredMethod"));
-    assertTrue(registry.cloneEventTemplate(index, "") != null);
+  @Test
+  public void testCloneEventTemplate() throws Exception {
+    Integer index = registry.register(buildCloneableEventTemplate().getDeclaredMethod("registeredMethod"));
+    assertTrue(registry.buildCallEvent(index) != null);
+  }
 
+  @Test
+  public void testUnknownEventTemplate() throws Exception {
     thrown.expect(UnknownEventException.class);
-    registry.cloneEventTemplate(Integer.MAX_VALUE, "");
+    registry.buildCallEvent(Integer.MAX_VALUE);
   }
 }