Merge pull request #97 from maxmind/greg/improve-exception

Improve exception message and include cause

Author: horgh

CHANGELOG.md

@@ -1,6 +1,12 @@
 CHANGELOG
 =========
 
+2.1.0
+------------------
+
+* Messages for `DeserializationException` have been improved and the
+  cause is included, if any.
+
 2.0.0 (2020-10-13)
 ------------------
 

src/main/java/com/maxmind/db/Decoder.java

@@ -294,7 +294,7 @@ private <T, V> List<V> decodeArray(
             try {
                 constructor = cls.getConstructor(Integer.TYPE);
             } catch (NoSuchMethodException e) {
-                throw new DeserializationException("No constructor found for the List: " + e);
+                throw new DeserializationException("No constructor found for the List: " + e.getMessage(), e);
             }
             Object[] parameters = {size};
             try {
@@ -304,7 +304,7 @@ private <T, V> List<V> decodeArray(
             } catch (InstantiationException |
                     IllegalAccessException |
                     InvocationTargetException e) {
-                throw new DeserializationException("Error creating list: " + e);
+                throw new DeserializationException("Error creating list: " + e.getMessage(), e);
             }
         }
 
@@ -355,7 +355,7 @@ private <T, V> Map<String, V> decodeMapIntoMap(
             try {
                 constructor = cls.getConstructor(Integer.TYPE);
             } catch (NoSuchMethodException e) {
-                throw new DeserializationException("No constructor found for the Map: " + e);
+                throw new DeserializationException("No constructor found for the Map: " + e.getMessage(), e);
             }
             Object[] parameters = {size};
             try {
@@ -365,7 +365,7 @@ private <T, V> Map<String, V> decodeMapIntoMap(
             } catch (InstantiationException |
                     IllegalAccessException |
                     InvocationTargetException e) {
-                throw new DeserializationException("Error creating map: " + e);
+                throw new DeserializationException("Error creating map: " + e.getMessage(), e);
             }
         }
 
@@ -437,7 +437,7 @@ private <T> Object decodeMapIntoObject(int size, Class<T> cls)
         } catch (InstantiationException |
                 IllegalAccessException |
                 InvocationTargetException e) {
-            throw new DeserializationException("Error creating object: " + e);
+            throw new DeserializationException("Error creating object: " + e.getMessage(), e);
         }
     }
 

src/main/java/com/maxmind/db/DeserializationException.java

@@ -13,4 +13,7 @@ public class DeserializationException extends RuntimeException {
     DeserializationException(String message) {
         super(message);
     }
+    DeserializationException(String message, Throwable cause) {
+        super(message, cause);
+    }
 }