Trace object path for JSON validation errors.

4 files changed, 18 insertions, 16 deletions

diff --git a/lib/commons-lang3-3.3.2.jar b/lib/commons-lang3-3.3.2.jar
new file mode 100644
index 0000000..bb06979
--- /dev/null
+++ b/lib/commons-lang3-3.3.2.jar
diff --git a/nbproject/project.properties b/nbproject/project.properties
index d738523..f6acd32 100644
--- a/nbproject/project.properties
+++ b/nbproject/project.properties
@@ -29,13 +29,15 @@ dist.jar=${dist.dir}/Datafiller.jar
 dist.javadoc.dir=${dist.dir}/javadoc
 endorsed.classpath=
 excludes=
+file.reference.commons-lang3-3.3.2.jar=lib/commons-lang3-3.3.2.jar
 file.reference.gson-2.2.4.jar=lib/gson-2.2.4.jar
 file.reference.postgresql-9.3-1101.jdbc41.jar=lib/postgresql-9.3-1101.jdbc41.jar
 includes=**
 jar.compress=false
 javac.classpath=\
     ${file.reference.postgresql-9.3-1101.jdbc41.jar}:\
-    ${file.reference.gson-2.2.4.jar}
+    ${file.reference.gson-2.2.4.jar}:\
+    ${file.reference.commons-lang3-3.3.2.jar}
 # Space-separated list of extra javac options
 javac.compilerargs=
 javac.deprecation=false
diff --git a/src/data/ValidatingJsonDeserializer.java b/src/data/ValidatingJsonDeserializer.java
index e38f68f..511264d 100644
--- a/src/data/ValidatingJsonDeserializer.java
+++ b/src/data/ValidatingJsonDeserializer.java
@@ -26,14 +26,11 @@ public class ValidatingJsonDeserializer<T> implements JsonDeserializer<T> {
     public T deserialize(JsonElement je, Type type,
             JsonDeserializationContext jdc) throws JsonParseException {
         T obj = new Gson().fromJson(je, type);
-        checkObject(je, obj.getClass());
+        checkObject("", je, obj.getClass());
         return obj;
     }
 
-    private void checkObject(JsonElement je, Class type) {
-        if (!je.isJsonObject()) {
-            throw new JsonParseException("Expected object: " + type.getName());
-        }
+    private void checkObject(String path, JsonElement je, Class type) {
         JsonObject jsonObj = je.getAsJsonObject();
         for (Field f : type.getDeclaredFields()) {
             if (!jsonObj.has(f.getName())) {
@@ -41,14 +38,14 @@ public class ValidatingJsonDeserializer<T> implements JsonDeserializer<T> {
                     // null allowed, skip
                     continue;
                 }
-                throw new JsonParseException("Missing field: " + f.getName());
+                throw new JsonParseException("Missing field: " + path + f.getName());
             }
-            tryValidateProperty(jsonObj.get(f.getName()), f);
+            tryValidateProperty(path, jsonObj.get(f.getName()), f);
             // TODO: validate type?
         }
     }
 
-    private void tryValidateProperty(JsonElement je, Field f) {
+    private void tryValidateProperty(String path, JsonElement je, Field f) {
         // assume that this annotation is only applied to objects
         Validator v = f.getAnnotation(Validator.class);
         if (v != null) {
@@ -56,17 +53,19 @@ public class ValidatingJsonDeserializer<T> implements JsonDeserializer<T> {
             if (type.isArray()) {
                 // the class expects an array, so the value must have one too.
                 if (!je.isJsonArray()) {
-                    throw new JsonParseException("Not an array: " + f.getName());
+                    throw new JsonParseException("Not an array: " + path + f.getName());
                 }
                 JsonArray ja = je.getAsJsonArray();
                 type = type.getComponentType();
                 // for each array element, check if the object is valid.
+                path += f.getName() + "."; // e.g. foo[]
                 for (JsonElement arr_je : ja) {
-                    checkObject(arr_je, type);
+                    checkObject(path, arr_je, type);
                 }
             } else {
                 // not an array, assume a verifiable object
-                checkObject(je, type);
+                path += f.getName() + "."; // e.g. foo
+                checkObject(path, je, type);
             }
         }
     }
diff --git a/test/data/ValidatingJsonDeserializerTest.java b/test/data/ValidatingJsonDeserializerTest.java
index 19ec2f4..84dde5c 100644
--- a/test/data/ValidatingJsonDeserializerTest.java
+++ b/test/data/ValidatingJsonDeserializerTest.java
@@ -6,6 +6,7 @@ import com.google.gson.JsonArray;
 import com.google.gson.JsonNull;
 import com.google.gson.JsonObject;
 import com.google.gson.JsonParseException;
+import org.apache.commons.lang3.StringUtils;
 import org.junit.Test;
 import static org.junit.Assert.*;
 
@@ -387,7 +388,7 @@ public class ValidatingJsonDeserializerTest {
     private void checkImpairedTweet(String... names) {
         JsonObject tweet = buildMinimalTweet(buildMinimalUser());
         removeProperty(tweet, names);
-        String prop = names[names.length - 1];
+        String prop = StringUtils.join(names, ".");
         checkTweetFail(tweet, "Missing field: " + prop);
     }
 
@@ -395,8 +396,8 @@ public class ValidatingJsonDeserializerTest {
         JsonObject user = buildMinimalUser();
         removeProperty(user, names);
         JsonObject tweet = buildMinimalTweet(user);
-        String prop = names[names.length - 1];
-        checkTweetFail(tweet, "Missing field: " + prop);
+        String prop = StringUtils.join(names, ".");
+        checkTweetFail(tweet, "Missing field: user." + prop);
     }
 
     private void checkTweetFail(JsonObject tweet, String exp) {
@@ -486,6 +487,6 @@ public class ValidatingJsonDeserializerTest {
         JsonObject retweet = buildMinimalTweet(buildMinimalUser());
         removeProperty(retweet, "text");
         tweet.add("retweeted_status", retweet);
-        checkTweetFail(tweet, "Missing field: text");
+        checkTweetFail(tweet, "Missing field: retweeted_status.text");
     }
 }