improved path error messages

json-assert/src/main/java/com/jayway/jsonassert/InvalidPathException.java

@@ -6,4 +6,19 @@ package com.jayway.jsonassert;
  * Time: 10:09 AM
  */
 public class InvalidPathException extends RuntimeException {
+
+    public InvalidPathException() {
+    }
+
+    public InvalidPathException(String message) {
+        super(message);
+    }
+
+    public InvalidPathException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+    public InvalidPathException(Throwable cause) {
+        super(cause);
+    }
 }

json-assert/src/main/java/com/jayway/jsonassert/impl/JSONPathFragment.java

@@ -22,10 +22,31 @@ class JSONPathFragment {
         this.fragment = fragment;
     }
 
-    String fragment() {
+    String value() {
         return fragment;
     }
 
+    String appendToPath(String path){
+        StringBuilder builder = new StringBuilder(path);
+
+        if(ARRAY_POSITION_PATTER.matcher(fragment).matches()){
+            builder.append("[").append(getArrayIndex()).append("]");
+        }
+        else if(GROOVY_POSITION_PATTER.matcher(fragment).matches()){
+            builder.append(path.isEmpty()?"":".").append("get(").append(getArrayIndex()).append(")");
+        }
+        else if(ARRAY_WILDCARD_PATTER.matcher(fragment).matches()){
+            builder.append("[*]");
+        }
+        else if(GROOVY_WILDCARD_PATTER.matcher(fragment).matches()){
+            builder.append(path.isEmpty()?"":".").append("get(*)");
+        }
+        else {
+           builder.append(path.isEmpty()?"":".").append(fragment);
+        }
+        return builder.toString();
+    }
+
     boolean isArrayIndex() {
         return ARRAY_POSITION_PATTER.matcher(fragment).matches() || GROOVY_POSITION_PATTER.matcher(fragment).matches();
     }

json-assert/src/main/java/com/jayway/jsonassert/impl/JSONReaderImpl.java

@@ -26,6 +26,7 @@ public class JSONReaderImpl implements JSONReader {
     private static final JSONParser JSON_PARSER = new JSONParser();
 
     private Object root;
+    private String currentPath;
 
 
     public static synchronized JSONReader parse(Reader reader) throws java.text.ParseException, IOException {
@@ -130,27 +131,32 @@ public class JSONReaderImpl implements JSONReader {
 
 
     private <T> T getByPath(Class<T> clazz, String stringPath) {
+        currentPath = "";
         Object current = this.root;
         JSONPath path = new JSONPath(stringPath);
 
         while (path.hasMoreFragments()) {
+
             JSONPathFragment fragment = path.nextFragment();
+
+            currentPath = fragment.appendToPath(currentPath);
+
             if (fragment.isArrayIndex()) {
-                current = getArray(current).get(fragment.getArrayIndex());
+                current = toArray(current).get(fragment.getArrayIndex());
             } else if (fragment.isArrayWildcard()) {
-                current = getContainerValue(current, path.nextFragment().fragment());
+                current = getContainerValue(current, path.nextFragment());
             } else {
-                current = getContainerValue(current, fragment.fragment());
+                current = getContainerValue(current, fragment);
             }
         }
         return clazz.cast(current);
     }
 
-    private JSONArray getArray(Object array) {
+    private JSONArray toArray(Object array) {
         return (JSONArray) array;
     }
 
-    private JSONObject getDocument(Object document) {
+    private JSONObject toDocument(Object document) {
         return (JSONObject) document;
     }
 
@@ -161,32 +167,30 @@ public class JSONReaderImpl implements JSONReader {
      * will be returned in a List
      *
      * @param container a json document or array
-     * @param field     the field to extract from the document alt. the documents contained in the array
+     * @param fragment the field to extract from the document alt. the documents contained in the array
      * @return a single field value or a List of fields
      */
-    private Object getContainerValue(Object container, Object field) {
+    private Object getContainerValue(Object container, JSONPathFragment fragment) {
         Object result;
 
         if (container instanceof JSONArray) {
             List list = new LinkedList();
-            for (Object doc : getArray(container)) {
-                list.add(getContainerValue(doc, field));
+            for (Object doc : toArray(container)) {
+                list.add(getContainerValue(doc, fragment));
             }
             result = list;
 
         } else if (container instanceof JSONObject) {
-            JSONObject document = getDocument(container);
+            JSONObject document = toDocument(container);
 
-            if (!document.containsKey(field)) {
-                throw new InvalidPathException();
+            if (!document.containsKey(fragment.value())) {
+                throw new InvalidPathException("Invalid path element: " + currentPath + " <==");
             }
 
-            result = document.get(field);
+            result = document.get(fragment.value());
         } else {
-            throw new UnsupportedOperationException("can not get value from " + container.getClass().getName());
+            throw new InvalidPathException("Invalid path element: " + currentPath + " <==");
         }
-        //notNull(result, "invalid path: " + field);
-
         return result;
     }
 }

json-assert/src/test/java/com/jayway/jsonassert/JSONReaderTest.java

@@ -93,6 +93,9 @@ public class JSONReaderTest {
 
     @Test
     public void a_path_can_be_checked_for_non_existence() throws Exception {
+
+
+
         JSONReader reader = JSONAssert.parse(TEST_DEEP_PATH_DOCUMENT);
 
         assertFalse(reader.hasJsonPath("a.b.c.FOO"));

json-assert/src/test/resources/json-test-doc.json

@@ -1,18 +1,30 @@
 {
-	"id": 100,
-	"type": "donut",
-	"name": "Cake",
+    "id": 100,
+    "type": "donut",
+    "name": "Cake",
     "available": true,
-	"ppu": 0.55,
-	"batters":
-		{
-			"batter":
-				[
-					{ "id": "1001", "type": "Regular" },
-					{ "id": "1002", "type": "Chocolate" },
-					{ "id": "1003", "type": "Blueberry" },
-					{ "id": "1004", "type": "Devil's Food" }
-				]
-		},
-	"toppings": ["Glazed", "Sugar", "Chocolate", "Maple"]
+    "ppu": 0.55,
+    "batters":
+    {
+        "batter":
+                [
+                    {
+                        "id": "1001",
+                        "type": "Regular"
+                    },
+                    {
+                        "id": "1002",
+                        "type": "Chocolate"
+                    },
+                    {
+                        "id": "1003",
+                        "type": "Blueberry"
+                    },
+                    {
+                        "id": "1004",
+                        "type": "Devil's Food"
+                    }
+                ]
+    },
+    "toppings": ["Glazed", "Sugar", "Chocolate", "Maple"]
 }