1 files changed, 170 insertions, 6 deletions

diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/storage/file/WindowCacheStats.java b/org.eclipse.jgit/src/org/eclipse/jgit/storage/file/WindowCacheStats.java
index 3570733e41..b7f6394df6 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/storage/file/WindowCacheStats.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/storage/file/WindowCacheStats.java
@@ -40,29 +40,193 @@
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
-
 package org.eclipse.jgit.storage.file;
 
+import javax.management.MXBean;
+
 import org.eclipse.jgit.internal.storage.file.WindowCache;
 
 /**
- * Accessor for stats about {@link WindowCache}.
+ * Cache statistics for {@link WindowCache}.
  *
  * @since 4.11
- *
  */
-public class WindowCacheStats {
+@MXBean
+public interface WindowCacheStats {
 	/**
 	 * @return the number of open files.
+	 * @deprecated use {@link #getOpenFileCount()} instead
 	 */
+	@Deprecated
 	public static int getOpenFiles() {
-		return WindowCache.getInstance().getOpenFiles();
+		return (int) WindowCache.getInstance().getStats().getOpenFileCount();
 	}
 
 	/**
 	 * @return the number of open bytes.
+	 * @deprecated use {@link #getOpenByteCount()} instead
 	 */
+	@Deprecated
 	public static long getOpenBytes() {
-		return WindowCache.getInstance().getOpenBytes();
+		return WindowCache.getInstance().getStats().getOpenByteCount();
+	}
+
+	/**
+	 * @return cache statistics for the WindowCache
+	 * @since 5.1.13
+	 */
+	public static WindowCacheStats getStats() {
+		return WindowCache.getInstance().getStats();
+	}
+
+	/**
+	 * Number of cache hits
+	 *
+	 * @return number of cache hits
+	 */
+	long getHitCount();
+
+	/**
+	 * Ratio of cache requests which were hits defined as
+	 * {@code hitCount / requestCount}, or {@code 1.0} when
+	 * {@code requestCount == 0}. Note that {@code hitRate + missRate =~ 1.0}.
+	 *
+	 * @return the ratio of cache requests which were hits
+	 */
+	default double getHitRatio() {
+		long requestCount = getRequestCount();
+		return (requestCount == 0) ? 1.0
+				: (double) getHitCount() / requestCount;
+	}
+
+	/**
+	 * Number of cache misses.
+	 *
+	 * @return number of cash misses
+	 */
+	long getMissCount();
+
+	/**
+	 * Ratio of cache requests which were misses defined as
+	 * {@code missCount / requestCount}, or {@code 0.0} when
+	 * {@code requestCount == 0}. Note that {@code hitRate + missRate =~ 1.0}.
+	 * Cache misses include all requests which weren't cache hits, including
+	 * requests which resulted in either successful or failed loading attempts.
+	 *
+	 * @return the ratio of cache requests which were misses
+	 */
+	default double getMissRatio() {
+		long requestCount = getRequestCount();
+		return (requestCount == 0) ? 0.0
+				: (double) getMissCount() / requestCount;
+	}
+
+	/**
+	 * Number of successful loads
+	 *
+	 * @return number of successful loads
+	 */
+	long getLoadSuccessCount();
+
+	/**
+	 * Number of failed loads
+	 *
+	 * @return number of failed loads
+	 */
+	long getLoadFailureCount();
+
+	/**
+	 * Ratio of cache load attempts which threw exceptions. This is defined as
+	 * {@code loadFailureCount / (loadSuccessCount + loadFailureCount)}, or
+	 * {@code 0.0} when {@code loadSuccessCount + loadFailureCount == 0}.
+	 *
+	 * @return the ratio of cache loading attempts which threw exceptions
+	 */
+	default double getLoadFailureRatio() {
+		long loadFailureCount = getLoadFailureCount();
+		long totalLoadCount = getLoadSuccessCount() + loadFailureCount;
+		return (totalLoadCount == 0) ? 0.0
+				: (double) loadFailureCount / totalLoadCount;
 	}
+
+	/**
+	 * Total number of times that the cache attempted to load new values. This
+	 * includes both successful load operations, as well as failed loads. This
+	 * is defined as {@code loadSuccessCount + loadFailureCount}.
+	 *
+	 * @return the {@code loadSuccessCount + loadFailureCount}
+	 */
+	default long getLoadCount() {
+		return getLoadSuccessCount() + getLoadFailureCount();
+	}
+
+	/**
+	 * Number of cache evictions
+	 *
+	 * @return number of evictions
+	 */
+	long getEvictionCount();
+
+	/**
+	 * Ratio of cache evictions. This is defined as
+	 * {@code evictionCount / requestCount}, or {@code 0.0} when
+	 * {@code requestCount == 0}.
+	 *
+	 * @return the ratio of cache loading attempts which threw exceptions
+	 */
+	default double getEvictionRatio() {
+		long evictionCount = getEvictionCount();
+		long requestCount = getRequestCount();
+		return (requestCount == 0) ? 0.0
+				: (double) evictionCount / requestCount;
+	}
+
+	/**
+	 * Number of times the cache returned either a cached or uncached value.
+	 * This is defined as {@code hitCount + missCount}.
+	 *
+	 * @return the {@code hitCount + missCount}
+	 */
+	default long getRequestCount() {
+		return getHitCount() + getMissCount();
+	}
+
+	/**
+	 * Average time in nanoseconds for loading new values. This is
+	 * {@code totalLoadTime / (loadSuccessCount + loadFailureCount)}.
+	 *
+	 * @return the average time spent loading new values
+	 */
+	default double getAverageLoadTime() {
+		long totalLoadCount = getLoadSuccessCount() + getLoadFailureCount();
+		return (totalLoadCount == 0) ? 0.0
+				: (double) getTotalLoadTime() / totalLoadCount;
+	}
+
+	/**
+	 * Total time in nanoseconds the cache spent loading new values.
+	 *
+	 * @return the total number of nanoseconds the cache has spent loading new
+	 *         values
+	 */
+	long getTotalLoadTime();
+
+	/**
+	 * Number of pack files kept open by the cache
+	 *
+	 * @return number of files kept open by cache
+	 */
+	long getOpenFileCount();
+
+	/**
+	 * Number of bytes cached
+	 *
+	 * @return number of bytes cached
+	 */
+	long getOpenByteCount();
+
+	/**
+	 * Reset counters. Does not reset open bytes and open files counters.
+	 */
+	void resetCounters();
 }