From 13e55748a9a63c87a801ffb11a7a58b5fc944986 Mon Sep 17 00:00:00 2001
From: Ruben Dijkstra <rubendijkstra123@gmail.com>
Date: Mon, 8 Dec 2014 21:29:28 +0100
Subject: [PATCH] Validate whether an enum type is supplied in EnumConversion

---
 .../mysema/query/support/EnumConversion.java  | 21 +++++++++++--------
 .../query/support/EnumConversionTest.java     | 14 +++++++++++--
 2 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/querydsl-core/src/main/java/com/mysema/query/support/EnumConversion.java b/querydsl-core/src/main/java/com/mysema/query/support/EnumConversion.java
index 27598cf8f..cd31a5077 100644
--- a/querydsl-core/src/main/java/com/mysema/query/support/EnumConversion.java
+++ b/querydsl-core/src/main/java/com/mysema/query/support/EnumConversion.java
@@ -16,6 +16,7 @@ package com.mysema.query.support;
 import java.util.Collections;
 import java.util.List;
 
+import com.google.common.base.Preconditions;
 import com.mysema.query.types.Expression;
 import com.mysema.query.types.FactoryExpressionBase;
 import com.mysema.query.types.Visitor;
@@ -34,16 +35,14 @@ public class EnumConversion<T> extends FactoryExpressionBase<T> {
 
     private final List<Expression<?>> exprs;
 
-    private final Enum<?>[] values;
+    private final T[] values;
 
     public EnumConversion(Expression<T> expr) {
         super(expr.getType());
+        Class<? extends T> type = getType();
+        Preconditions.checkArgument(type.isEnum(), "%s is not an enum", type);
         exprs = Collections.<Expression<?>>singletonList(expr);
-        try {
-            values = (Enum<?>[]) expr.getType().getMethod("values").invoke(null);
-        } catch (Exception e) {
-            throw new RuntimeException(e.getMessage(), e);
-        }
+        values = type.getEnumConstants();
     }
 
     @Override
@@ -60,11 +59,15 @@ public class EnumConversion<T> extends FactoryExpressionBase<T> {
     public T newInstance(Object... args) {
         if (args[0] != null) {
             if (args[0] instanceof String) {
-                return (T)Enum.valueOf((Class)getType(), (String)args[0]);
+                @SuppressWarnings("unchecked") //The expression type is an enum
+                T rv = (T) Enum.valueOf(getType().asSubclass(Enum.class), (String)args[0]);
+                return rv;
             } else if (args[0] instanceof Number) {
-                return (T)values[((Number)args[0]).intValue()];
+                return values[((Number)args[0]).intValue()];
             } else {
-                return (T)args[0];
+                @SuppressWarnings("unchecked")
+                T rv = (T)args[0];
+                return rv;
             }
         } else {
             return null;
diff --git a/querydsl-core/src/test/java/com/mysema/query/support/EnumConversionTest.java b/querydsl-core/src/test/java/com/mysema/query/support/EnumConversionTest.java
index b82f5c00a..a42c09097 100644
--- a/querydsl-core/src/test/java/com/mysema/query/support/EnumConversionTest.java
+++ b/querydsl-core/src/test/java/com/mysema/query/support/EnumConversionTest.java
@@ -1,10 +1,12 @@
 package com.mysema.query.support;
 
 import static org.junit.Assert.assertEquals;
-
-import org.junit.Test;
+import static org.junit.Assert.fail;
 
 import com.mysema.query.types.path.EnumPath;
+import com.mysema.query.types.path.StringPath;
+
+import org.junit.Test;
 
 public class EnumConversionTest {
 
@@ -23,4 +25,12 @@ public class EnumConversionTest {
         EnumConversion<Color> conv = new EnumConversion<Color>(color);
         assertEquals(Color.RED, conv.newInstance(2));
     }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void Illegal() {
+        StringPath string = new StringPath("path");
+        EnumConversion<String> conv = new EnumConversion<String>(string);
+        fail("EnumConversion successfully created for a non-enum type");
+        conv.newInstance(0);
+    }
 }