Reuse LogEntry object to avoid excessive allocations when loading Timeline

Author: rbuch

src/projections/analysis/GenericLogReader.java

@@ -135,20 +135,29 @@ public LogEntry nextProcessingEvent() throws IOException, EndOfLogSuccess
 	{
 		return nextEventOfType(BEGIN_PROCESSING, END_PROCESSING);
 	}
-	
+
+	/**
+	 * Helper function which allocates new LogEntry object for nextEvent(LogEntry data)
+	 */
+	public LogEntry nextEvent() throws InputMismatchException, IOException, EndOfLogSuccess
+	{
+		LogEntry data = new LogEntry();
+		return nextEvent(data);
+	}
 
 	/** 
-	 * Create a new LogEntryData by reading/parsing the next line from the log 
+	 * Fill in a LogEntry by reading/parsing the next line from the log
 	 * 
 	 * Upon reaching the end of the file, a fake END_COMPUTATION event will be produced if none was found in the log file.
 	 * After the end of the file is reached and after some END_COMPUTATION has been returned, an EndOfLogException will be thrown
 	 * 
 	 * If any problem is detected when reading within a line, an IOException is produced
 	 * 
+	 * Use the LogEntry object passed in rather than allocating a new one to avoid excessive object creation,
+	 * particularly useful in Timeline
 	 * */
-	public LogEntry nextEvent() throws InputMismatchException, IOException, EndOfLogSuccess
+	public LogEntry nextEvent(LogEntry data) throws InputMismatchException, IOException, EndOfLogSuccess
 	{
-		LogEntry data = new LogEntry();
 		StsReader stsinfo = MainWindow.runObject[myRun].getSts();
 
 		String line = reader.readLine();

src/projections/analysis/LogLoader.java

@@ -211,7 +211,9 @@ public void createtimeline(int pe, long Begin, long End, Deque<TimelineEvent> ti
 				return;
 				}
 			}
-			//Throws EndOfLogException at end of file; break if past endTime
+			// Throws EndOfLogException at end of file; break if past endTime
+			// Note that the LE object is reused, filled with new data every iteration.
+			// Ensure that stale data from a past read for another type is not used.
 			CallStackManager cstack = new CallStackManager();
 			ObjectId tid = null;
 			while(true) {
@@ -420,7 +422,7 @@ public void createtimeline(int pe, long Begin, long End, Deque<TimelineEvent> ti
 
 						// Now, expect to read the second entry and handle
 						// errors if necessary.
-						LE = reader.nextEvent();
+						LE = reader.nextEvent(LE);
 
 						if (LE.type != USER_EVENT_PAIR) {
 							// DANGLING - throw away the old event
@@ -558,7 +560,7 @@ public void createtimeline(int pe, long Begin, long End, Deque<TimelineEvent> ti
 						break;
 					}
 				}
-				LE = reader.nextEvent();
+				LE = reader.nextEvent(LE);
 				// this will
 				// END COMPUTATION event.
 				if (LE.entry != -1) {