Merge pull request #110 from maxmind/sromani/better-reflection-exception

Add exception for argument mismatch in contructor

Author: oschwald

CHANGELOG.md

@@ -1,11 +1,11 @@
 CHANGELOG
 =========
-
 2.1.0
 ------------------
 
-* Messages for `DeserializationException` have been improved and the
-  cause is included, if any.
+* Messages for `DeserializationException` have been improved and the cause
+ is included, if any. Moreover, the message provides detail about the involved
+ types, if the exeption is caused by an `IllegalArgumentException`.
 
 2.0.0 (2020-10-13)
 ------------------

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

@@ -439,6 +439,17 @@ private <T> Object decodeMapIntoObject(int size, Class<T> cls)
                 InvocationTargetException e) {
             throw new DeserializationException("Error creating object: " + e.getMessage(), e);
         }
+        catch (IllegalArgumentException e){
+            StringBuilder sbErrors = new StringBuilder();  
+            for (String key : parameterIndexes.keySet()) {
+                int index = parameterIndexes.get(key);
+                if (!parameters[index].getClass().isAssignableFrom( parameterTypes[index])) {
+                    sbErrors.append(" argument type mismatch in " + key + " MMDB Type: " + parameters[index].getClass().getCanonicalName()
+                    + " Java Type: " +parameterTypes[index].getCanonicalName());
+                }              
+            }
+            throw new DeserializationException("Error creating object of type: " + cls.getSimpleName() + " - " + sbErrors.toString(), e);
+        }
     }
 
     private static <T> Constructor<T> findConstructor(Class<T> cls)

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

@@ -8,6 +8,7 @@
 import java.net.InetAddress;
 import java.nio.ByteBuffer;
 import java.util.concurrent.atomic.AtomicReference;
+import java.util.Optional;
 import java.util.concurrent.ConcurrentHashMap;
 
 /**
@@ -177,9 +178,13 @@ record = this.readNode(buffer, record, bit);
         T dataRecord = null;
         if (record > nodeCount) {
             // record is a data pointer
-            dataRecord = this.resolveDataPointer(buffer, record, cls);
+            try {
+                dataRecord = this.resolveDataPointer(buffer, record, cls);
+            } catch (DeserializationException exception) {
+                String msgCause = Optional.ofNullable(exception).map(Exception::getMessage).orElse("");
+                throw new DeserializationException("Error getting record for IP " + ipAddress.toString() + " -  " + msgCause, exception);
+            }
         }
-
         return new DatabaseRecord<>(dataRecord, ipAddress, pl);
     }
 

src/test/java/com/maxmind/db/ReaderTest.java

@@ -567,6 +567,61 @@ public TestModelSubdivision(
         }
     }
 
+    @Test
+    public void testDecodeWrongTypeWithConstructorException() throws IOException {
+        this.testReader = new Reader(getFile("GeoIP2-City-Test.mmdb"));
+        DeserializationException ex = assertThrows(DeserializationException.class,
+            () -> this.testReader.get( InetAddress.getByName("2.125.160.216"),
+            TestModelSubdivisionsWithUnknownException.class));
+        
+        assertThat(ex.getMessage(), containsString("Error getting record for IP /2.125.160.216 -  Error creating object"));
+    }
+
+    static class TestModelSubdivisionsWithUnknownException {
+        List<TestModelSubdivision> subdivisions;
+
+        @MaxMindDbConstructor
+        public TestModelSubdivisionsWithUnknownException (
+            @MaxMindDbParameter(name="subdivisions")
+            List<TestModelSubdivision> subdivisions
+        ) throws Exception{
+            throw new Exception();
+        }
+    }
+
+    @Test
+    public void testDecodeWrongTypeWithWrongArguments() throws IOException {
+        this.testReader = new Reader(getFile("GeoIP2-City-Test.mmdb"));
+        DeserializationException ex = assertThrows(DeserializationException.class,
+            () -> this.testReader.get( InetAddress.getByName("2.125.160.216"),
+            TestWrongModelSubdivisions.class));
+        assertThat(ex.getMessage(), containsString("Error getting record for IP"));
+    }
+
+    static class TestWrongModelSubdivisions {
+        List<TestWrongModelSubdivision> subdivisions;
+
+        @MaxMindDbConstructor
+        public TestWrongModelSubdivisions (
+            @MaxMindDbParameter(name="subdivisions")
+            List<TestWrongModelSubdivision> subdivisions
+        ) {
+            this.subdivisions = subdivisions;
+        }
+    }
+
+    static class TestWrongModelSubdivision {
+        Integer uint16Field;
+        @MaxMindDbConstructor
+        public TestWrongModelSubdivision(
+            @MaxMindDbParameter(name="iso_code")
+            Integer uint16Field
+            ) {
+            this.uint16Field = uint16Field;
+            ;
+        }
+    }
+
     @Test
     public void testDecodeConcurrentHashMap() throws IOException {
         this.testReader = new Reader(getFile("GeoIP2-City-Test.mmdb"));
@@ -775,7 +830,7 @@ public void voidTestMapKeyIsString() throws IOException {
                 TestModelInvalidMap.class
             )
         );
-        assertEquals("Map keys must be strings.", ex.getMessage());
+        assertEquals("Error getting record for IP /2.125.160.216 -  Map keys must be strings.", ex.getMessage());
     }
 
     static class TestModelInvalidMap {