WIP: combinations for flattening facets to keys.

src/main/java/net/helenus/core/AbstractUnitOfWork.java

@@ -18,6 +18,7 @@ package net.helenus.core;
 import java.util.*;
 
 import com.diffplug.common.base.Errors;
+import com.google.common.base.Stopwatch;
 import com.google.common.cache.Cache;
 import com.google.common.collect.HashBasedTable;
 import com.google.common.collect.Table;
@@ -36,7 +37,7 @@ public abstract class AbstractUnitOfWork<E extends Exception> implements UnitOfW
 
 	private String purpose_;
 	private Stopwatch elapsedTime_;
-    public Stopwatch databaseTime_;
+	public Stopwatch databaseTime_ = Stopwatch.createUnstarted();
 
 	// Cache:
 	private final Table<String, String, Object> cache = HashBasedTable.create();
@@ -48,6 +49,11 @@ public abstract class AbstractUnitOfWork<E extends Exception> implements UnitOfW
 		this.parent = parent;
 	}
 
+	@Override
+	public Stopwatch getExecutionTimer() {
+		return databaseTime_;
+	}
+
 	@Override
 	public void addNestedUnitOfWork(UnitOfWork<E> uow) {
 		synchronized (nested) {
@@ -57,6 +63,7 @@ public abstract class AbstractUnitOfWork<E extends Exception> implements UnitOfW
 
 	@Override
 	public UnitOfWork<E> begin() {
+		elapsedTime_.start();
 		// log.record(txn::start)
 		return this;
 	}
@@ -91,12 +98,18 @@ public abstract class AbstractUnitOfWork<E extends Exception> implements UnitOfW
 			// Be sure to check all enclosing UnitOfWork caches as well, we may be nested.
 			if (parent != null) {
 				return parent.cacheLookup(facets);
-			} else {
+			}/* else {
 				Cache<String, Object> cache = session.getSessionCache();
-
-			    cache.getIfPresent(key)
+				String[] keys = flattenFacets(facets);
+				for (String key : keys) {
+					Object value = cache.getIfPresent(key);
+					if (value != null) {
+						result = Optional.of(value);
+						break;
 					}
 				}
+			}*/
+		}
 		return result;
 	}
 
@@ -150,10 +163,22 @@ public abstract class AbstractUnitOfWork<E extends Exception> implements UnitOfW
 			// Merge UOW cache into parent's cache.
 			if (parent != null) {
 				parent.mergeCache(cache);
-			} else {
+			} /*else {
 			    Cache<String, Object> cache = session.getSessionCache();
+				Map<String, Object> rowMap = this.cache.rowMap();
+				for (String rowKey : rowMap.keySet()) {
+					String keys = flattenFacets(facets);
+					for (String key : keys) {
+						Object value = cache.getIfPresent(key);
+						if (value != null) {
+							result = Optional.of(value);
+							break;
+						}
+					}
+				}
 			    cache.put
             }
+			*/
 
 			// Apply all post-commit functions for
 			if (parent == null) {

src/main/java/net/helenus/core/UnitOfWork.java

@@ -18,6 +18,7 @@ package net.helenus.core;
 import java.util.List;
 import java.util.Optional;
 
+import com.google.common.base.Stopwatch;
 import net.helenus.core.cache.Facet;
 
 public interface UnitOfWork<X extends Exception> extends AutoCloseable {
@@ -56,4 +57,6 @@ public interface UnitOfWork<X extends Exception> extends AutoCloseable {
 	Optional<Object> cacheLookup(List<Facet> facets);
 
 	void cacheUpdate(Object pojo, List<Facet> facets);
+
+	Stopwatch getExecutionTimer();
 }

src/main/java/net/helenus/core/cache/CacheUtil.java

@@ -0,0 +1,30 @@
+package net.helenus.core.cache;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+public class CacheUtil {
+    public static List<String[]> comb(String... items) {
+        int n = items.length;
+        if (n > 20 || n < 0) throw new IllegalArgumentException(n + " is out of range");
+        long e = Math.round(Math.pow(2, n));
+        List<String[]> out = new ArrayList<String[]>((int) e - 1);
+        Arrays.sort(items);
+        for (int k = 1; k <= items.length; k++) {
+            kcomb(items, 0, k, new String[k], out);
+        }
+        return out;
+    }
+
+    private static void kcomb(String[] items, int n, int k, String[] arr, List<String[]> out) {
+        if (k == 0) {
+            out.add(arr.clone());
+        } else {
+            for (int i = n; i <= items.length - k; i++) {
+                arr[arr.length - k] = items[i];
+                kcomb(items, i + 1, k - 1, arr, out);
+            }
+        }
+    }
+}

src/main/java/net/helenus/core/operation/Operation.java

@@ -29,6 +29,7 @@ import com.datastax.driver.core.Statement;
 import brave.Span;
 import brave.Tracer;
 import brave.propagation.TraceContext;
+import com.google.common.base.Stopwatch;
 import net.helenus.core.AbstractSessionOperations;
 import net.helenus.core.UnitOfWork;
 import net.helenus.core.cache.Facet;
@@ -67,8 +68,13 @@ public abstract class Operation<E> {
 			}
 
 			Statement statement = options(buildStatement(cached));
+			Stopwatch timer = uow.getExecutionTimer();
+			timer.start();
 			ResultSetFuture futureResultSet = session.executeAsync(statement, showValues);
-            return futureResultSet.getUninterruptibly(); //TODO(gburd): (timeout, units);
+			ResultSet resultSet = futureResultSet.getUninterruptibly(); //TODO(gburd): (timeout, units);
+			timer.stop();
+            return resultSet;
+
 		} finally {
 
 			if (span != null) {