Added "preload all" functionality and unit tests for same

src/main/java/edu/jhuapl/tinkerpop/AccumuloGraph.java

@@ -155,11 +155,12 @@ public class AccumuloGraph implements Graph, KeyIndexableGraph, IndexableGraph {
       // any "preloaded" properties now, which saves us a round-trip
       // to Accumulo later.
       String[] preload = globals.getConfig().getPreloadedProperties();
-      if (preload == null) {
+      if (preload == null && !globals.getConfig().getPreloadAllProperties()) {
         preload = new String[]{};
       }
 
-      Map<String, Object> props = globals.getVertexWrapper().readProperties(vertex, preload);
+      Map<String, Object> props = globals.getVertexWrapper()
+          .readProperties(vertex, preload);
       if (props == null) {
         return null;
       }

src/main/java/edu/jhuapl/tinkerpop/AccumuloGraphConfiguration.java

@@ -1036,17 +1036,17 @@ implements Serializable {
       }
     }
 
-    if (timeout <= 0 && conf.getProperty(Keys.PRELOADED_PROPERTIES) != null) {
-      throw new IllegalArgumentException("You cannot preload properties "
-          + "without first setting #propertyCacheTimeout(String property, int millis) "
-          + "to a positive value.");
-    }
-
     if (getPreloadAllProperties() && getPreloadedProperties() != null) {
       throw new IllegalArgumentException("Cannot preload all properties"
           + " and specified properties simultaneously");
     }
-  }
+
+    if (timeout <= 0 && (getPreloadedProperties() != null || getPreloadAllProperties())) {
+      throw new IllegalArgumentException("You cannot preload properties "
+          + "without first setting #propertyCacheTimeout(String property, int millis) "
+          + "to a positive value.");
+    }
+}
 
   private void checkPropertyValue(String prop, String val, boolean canBeEmpty) {
     if (val == null) {

src/test/java/edu/jhuapl/tinkerpop/ElementPropertyCachingTest.java

@@ -221,6 +221,26 @@ public class ElementPropertyCachingTest {
     graph.shutdown();
   }
 
+  @Test
+  public void testPreloadAllProperties() {
+    AccumuloGraphConfiguration cfg =
+        AccumuloGraphTestUtils.generateGraphConfig("preloadAllProperties");
+    cfg.setPropertyCacheTimeout(null, TIMEOUT);
+    cfg.setPreloadAllProperties(true);
+
+    Graph graph = open(cfg);
+
+    AccumuloVertex v = (AccumuloVertex) graph.addVertex("V");
+    v.setProperty(NON_CACHED, true);
+    v.setProperty(CACHED, true);
+
+    v = (AccumuloVertex) graph.getVertex("V");
+    assertEquals(true, v.getPropertyInMemory(NON_CACHED));
+    assertEquals(true, v.getPropertyInMemory(CACHED));
+
+    graph.shutdown();
+  }
+
   @Test
   public void testPreloadSomeProperties() {
     AccumuloGraphConfiguration cfg =