- * To automatically track startup performance in an app or applet,
- * use the command-line parameter sun.perflog as follows:
- *
}" will cause
- * that given filename to be created and used for all output.
- *
- * By default, times are measured using System.currentTimeMillis(). To use
- * System.nanoTime() instead, add the command-line parameter:
- -Dsun.perflog.nano=true
- *
- *
- * Warning: Use at your own risk!
- * This class is intended for internal testing
- * purposes only and may be removed at any time. More
- * permanent monitoring and profiling APIs are expected to be
- * developed for future releases and this class will cease to
- * exist once those APIs are in place.
- * @author Chet Haase
- */
-public class PerformanceLogger {
-
- // Timing values of global interest
- private static final int START_INDEX = 0; // VM start
- private static final int LAST_RESERVED = START_INDEX;
-
- private static boolean perfLoggingOn = false;
- private static boolean useNanoTime = false;
- private static Vector times;
- private static String logFileName = null;
- private static Writer logWriter = null;
- private static long baseTime;
-
- static {
- String perfLoggingProp =
- java.security.AccessController.doPrivileged(
- new sun.security.action.GetPropertyAction("sun.perflog"));
- if (perfLoggingProp != null) {
- perfLoggingOn = true;
-
- // Check if we should use nanoTime
- String perfNanoProp =
- java.security.AccessController.doPrivileged(
- new sun.security.action.GetPropertyAction("sun.perflog.nano"));
- if (perfNanoProp != null) {
- useNanoTime = true;
- }
-
- // Now, figure out what the user wants to do with the data
- if (perfLoggingProp.regionMatches(true, 0, "file:", 0, 5)) {
- logFileName = perfLoggingProp.substring(5);
- }
- if (logFileName != null) {
- if (logWriter == null) {
- java.security.AccessController.doPrivileged(
- new java.security.PrivilegedAction() {
- public Void run() {
- try {
- File logFile = new File(logFileName);
- logFile.createNewFile();
- logWriter = new FileWriter(logFile);
- } catch (Exception e) {
- System.out.println(e + ": Creating logfile " +
- logFileName +
- ". Log to console");
- }
- return null;
- }
- });
- }
- }
- if (logWriter == null) {
- logWriter = new OutputStreamWriter(System.out);
- }
- }
- times = new Vector(10);
- // Reserve predefined slots
- for (int i = 0; i <= LAST_RESERVED; ++i) {
- times.add(new TimeData("Time " + i + " not set", 0));
- }
- }
-
- /**
- * Returns status of whether logging is enabled or not. This is
- * provided as a convenience method so that users do not have to
- * perform the same GetPropertyAction check as above to determine whether
- * to enable performance logging.
- */
- public static boolean loggingEnabled() {
- return perfLoggingOn;
- }
-
-
- /**
- * Internal class used to store time/message data together.
- */
- static class TimeData {
- String message;
- long time;
-
- TimeData(String message, long time) {
- this.message = message;
- this.time = time;
- }
-
- String getMessage() {
- return message;
- }
-
- long getTime() {
- return time;
- }
- }
-
- /**
- * Return the current time, in millis or nanos as appropriate
- */
- private static long getCurrentTime() {
- if (useNanoTime) {
- return System.nanoTime();
- } else {
- return System.currentTimeMillis();
- }
- }
-
- /**
- * Sets the start time. Ideally, this is the earliest time available
- * during the startup of a Java applet or application. This time is
- * later used to analyze the difference between the initial startup
- * time and other events in the system (such as an applet's init time).
- */
- public static void setStartTime(String message) {
- if (loggingEnabled()) {
- long nowTime = getCurrentTime();
- setStartTime(message, nowTime);
- }
- }
-
- /**
- * Sets the base time, output can then
- * be displayed as offsets from the base time;.
- */
- public static void setBaseTime(long time) {
- if (loggingEnabled()) {
- baseTime = time;
- }
- }
-
- /**
- * Sets the start time.
- * This version of the method is
- * given the time to log, instead of expecting this method to
- * get the time itself. This is done in case the time was
- * recorded much earlier than this method was called.
- */
- public static void setStartTime(String message, long time) {
- if (loggingEnabled()) {
- times.set(START_INDEX, new TimeData(message, time));
- }
- }
-
- /**
- * Gets the start time, which should be the time when
- * the java process started, prior to the VM actually being
- * loaded.
- */
- public static long getStartTime() {
- if (loggingEnabled()) {
- return times.get(START_INDEX).getTime();
- } else {
- return 0;
- }
- }
-
- /**
- * Sets the value of a given time and returns the index of the
- * slot that that time was stored in.
- */
- public static int setTime(String message) {
- if (loggingEnabled()) {
- long nowTime = getCurrentTime();
- return setTime(message, nowTime);
- } else {
- return 0;
- }
- }
-
- /**
- * Sets the value of a given time and returns the index of the
- * slot that that time was stored in.
- * This version of the method is
- * given the time to log, instead of expecting this method to
- * get the time itself. This is done in case the time was
- * recorded much earlier than this method was called.
- */
- public static int setTime(String message, long time) {
- if (loggingEnabled()) {
- // times is already synchronized, but we need to ensure that
- // the size used in times.set() is the same used when returning
- // the index of that operation.
- synchronized (times) {
- times.add(new TimeData(message, time));
- return (times.size() - 1);
- }
- } else {
- return 0;
- }
- }
-
- /**
- * Returns time at given index.
- */
- public static long getTimeAtIndex(int index) {
- if (loggingEnabled()) {
- return times.get(index).getTime();
- } else {
- return 0;
- }
- }
-
- /**
- * Returns message at given index.
- */
- public static String getMessageAtIndex(int index) {
- if (loggingEnabled()) {
- return times.get(index).getMessage();
- } else {
- return null;
- }
- }
-
- /**
- * Outputs all data to parameter-specified Writer object
- */
- public static void outputLog(Writer writer) {
- if (loggingEnabled()) {
- try {
- synchronized(times) {
- for (int i = 0; i < times.size(); ++i) {
- TimeData td = times.get(i);
- if (td != null) {
- writer.write(i + " " + td.getMessage() + ": " +
- (td.getTime() - baseTime) + "\n");
-
- }
- }
- }
- writer.flush();
- } catch (Exception e) {
- System.out.println(e + ": Writing performance log to " +
- writer);
- }
- }
- }
-
- /**
- * Outputs all data to whatever location the user specified
- * via sun.perflog command-line parameter.
- */
- public static void outputLog() {
- outputLog(logWriter);
- }
-}