From dc9c228e4a3c2c233bd971cfd2a9c02e911d489f Mon Sep 17 00:00:00 2001
From: Greg Burd <gburd@onshape.com>
Date: Sun, 22 Oct 2017 22:04:20 -0400
Subject: [PATCH] WIP: flattenFacets

---
 .../net/helenus/core/AbstractUnitOfWork.java  | 23 +++++++++++++++++--
 .../net/helenus/core/cache/CacheUtil.java     |  4 +++-
 2 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/src/main/java/net/helenus/core/AbstractUnitOfWork.java b/src/main/java/net/helenus/core/AbstractUnitOfWork.java
index 89b9f26..8779a75 100644
--- a/src/main/java/net/helenus/core/AbstractUnitOfWork.java
+++ b/src/main/java/net/helenus/core/AbstractUnitOfWork.java
@@ -16,6 +16,7 @@
 package net.helenus.core;
 
 import java.util.*;
+import java.util.stream.Collectors;
 
 import com.diffplug.common.base.Errors;
 import com.google.common.base.Stopwatch;
@@ -24,6 +25,7 @@ import com.google.common.collect.HashBasedTable;
 import com.google.common.collect.Table;
 import com.google.common.collect.TreeTraverser;
 
+import net.helenus.core.cache.CacheUtil;
 import net.helenus.core.cache.Facet;
 
 /** Encapsulates the concept of a "transaction" as a unit-of-work. */
@@ -98,7 +100,7 @@ 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();
 				String[] keys = flattenFacets(facets);
 				for (String key : keys) {
@@ -108,7 +110,7 @@ public abstract class AbstractUnitOfWork<E extends Exception> implements UnitOfW
 						break;
 					}
 				}
-			}*/
+			}
 		}
 		return result;
 	}
@@ -123,6 +125,23 @@ public abstract class AbstractUnitOfWork<E extends Exception> implements UnitOfW
 		}
 	}
 
+	private String[] flattenFacets(List<Facet> facets) {
+		Facet table = facets.remove(0);
+		String tableName = table.value().toString();
+
+		List<String[]> combinations = CacheUtil.combinations(facets.stream()
+				.map(facet -> {
+					return facet.name() + "==" + facet.value();
+				}).collect(Collectors.toList()).toArray(new String[facets.size()]));
+
+		int i = 0;
+		String[] results = new String[facets.size()];
+		for (String[] combination : combinations) {
+			results[i++] = tableName + "." + combination;
+		}
+		return results;
+	}
+
 	private Iterator<AbstractUnitOfWork<E>> getChildNodes() {
 		return nested.iterator();
 	}
diff --git a/src/main/java/net/helenus/core/cache/CacheUtil.java b/src/main/java/net/helenus/core/cache/CacheUtil.java
index ef26818..89f4769 100644
--- a/src/main/java/net/helenus/core/cache/CacheUtil.java
+++ b/src/main/java/net/helenus/core/cache/CacheUtil.java
@@ -5,7 +5,8 @@ import java.util.Arrays;
 import java.util.List;
 
 public class CacheUtil {
-    public static List<String[]> comb(String... items) {
+
+    public static List<String[]> combinations(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));
@@ -27,4 +28,5 @@ public class CacheUtil {
             }
         }
     }
+
 }