Clean element.is.than error handling

Two fixes:
- 'less' is now permitted in addition to 'LESS' (case-insensitive)
- a fully bad operator (EG '.is[potato]') will respond with a simple
error message rather than a full stacktrace.

Also, player.target, return Element.NULL rather than a real null
pointer.

src/main/java/net/aufdemrand/denizen/objects/Element.java

@@ -236,11 +236,22 @@ public String getAttribute(Attribute attribute) {
 
             // Operator is the value of the .is[] context. Valid are Comparable.Operators, same
             // as used by the IF command.
-            com.setOperator(Comparable.Operator.valueOf(operator
-                    .replace("==", "EQUALS").replace(">=", "OR_MORE").replace("<=", "OR_LESS")
-                    .replace("<", "LESS").replace(">", "MORE").replace("=", "EQUALS")));
+            Comparable.Operator comparableOperator = null;
+            try {
+                comparableOperator = Comparable.Operator.valueOf(operator.replace("==", "EQUALS")
+                        .replace(">=", "OR_MORE").replace("<=", "OR_LESS").replace("<", "LESS")
+                        .replace(">", "MORE").replace("=", "EQUALS").toUpperCase());
+            }
+            catch (IllegalArgumentException e) { }
+
+            if (comparableOperator != null) {
+                com.setOperator(comparableOperator);
 
-            return new Element(com.determineOutcome()).getAttribute(attribute.fulfill(2));
+                return new Element(com.determineOutcome()).getAttribute(attribute.fulfill(2));
+            }
+            else {
+                dB.echoError("Unknown operator '" + operator + "'.");
+            }
         }
 
 

src/main/java/net/aufdemrand/denizen/objects/dPlayer.java

@@ -412,14 +412,14 @@ public String getAttribute(Attribute attribute) {
         /////////////////////
         //   ENTITY LIST ATTRIBUTES
         /////////////////
-        
+
         // <--[tag]
         // @attribute <p@player.target>
         // @returns dEntity
         // @description
         // Returns Entity that the player is looking at in 50 range.
         // -->
-        
+
         if (attribute.startsWith("target")) {
             int range = 50;
             int attribs = 1;
@@ -443,27 +443,27 @@ public String getAttribute(Attribute attribute) {
                     possibleTargets.add((LivingEntity) entity);
                 }
             }
-            
+
             // Find the valid target
             BlockIterator bi;
             try {
                 bi = new BlockIterator(getPlayerEntity(), range);
             }
             catch (IllegalStateException e) {
-                return null;
+                return Element.NULL.getAttribute(attribute.fulfill(attribs));
             }
             Block b;
             Location l;
             int bx, by, bz;
             double ex, ey, ez;
-            
+
             // Loop through player's line of sight
             while (bi.hasNext()) {
                 b = bi.next();
                 bx = b.getX();
                 by = b.getY();
                 bz = b.getZ();
-                
+
                 if (b.getType() != Material.AIR) {
                     // Line of sight is broken
                     break;
@@ -475,7 +475,7 @@ public String getAttribute(Attribute attribute) {
                         ex = l.getX();
                         ey = l.getY();
                         ez = l.getZ();
-                        
+
                         if ((bx - .75 <= ex && ex <= bx + 1.75) &&
                             (bz - .75 <= ez && ez <= bz + 1.75) &&
                             (by - 1 <= ey && ey <= by + 2.5)) {
@@ -487,7 +487,7 @@ public String getAttribute(Attribute attribute) {
             }
             return Element.NULL.getAttribute(attribute.fulfill(attribs));
         }
-        
+
         // <--[tag]
         // @attribute <p@player.list>
         // @returns dList(dPlayer)