Null handling tests.

json-path/src/main/java/com/jayway/jsonpath/internal/filter/FieldFilter.java

@@ -37,7 +37,7 @@ public class FieldFilter extends PathTokenFilter {
     public Object filter(Object obj, JsonProvider jsonProvider, LinkedList<Filter> filters, boolean inArrayContext) {
         if (jsonProvider.isArray(obj)) {
             if (!inArrayContext) {
-                throw new PathNotFoundException("Trying to access the field '" + condition +"' in an array context.");
+                throw new PathNotFoundException("Path '" + condition + "' is being applied to an array. Arrays can not have attributes.");
             } else {
                 Object result = jsonProvider.createArray();
                 for (Object current : jsonProvider.toIterable(obj)) {
@@ -73,7 +73,7 @@ public class FieldFilter extends PathTokenFilter {
 
             Collection<String> keys = jsonProvider.getPropertyKeys(obj);
             if(!keys.contains(condition) && split.length == 1){
-                throw new PathNotFoundException("Path '" + condition + "' not found in the current context.");
+                throw new PathNotFoundException("Path '" + condition + "' not found in the current context:\n" + jsonProvider.toJson(obj));
             } else {
 
                 if(split.length == 1){
@@ -87,11 +87,9 @@ public class FieldFilter extends PathTokenFilter {
                     }
                     return res;
                 }
-
-
             }
         } else {
-            throw new PathNotFoundException();
+            throw new PathNotFoundException("Failed to access property: " + condition + " on object " + obj);
         }
     }
 

json-path/src/test/java/com/jayway/jsonpath/NullHandlingTest.java

@@ -0,0 +1,68 @@
+package com.jayway.jsonpath;
+
+import org.hamcrest.Matchers;
+import org.junit.Test;
+
+import java.util.List;
+import java.util.Map;
+
+import static junit.framework.Assert.assertEquals;
+import static org.hamcrest.MatcherAssert.assertThat;
+
+/**
+ * User: kalle
+ * Date: 8/22/13
+ * Time: 10:39 AM
+ */
+public class NullHandlingTest {
+
+    public static final String DOCUMENT = "{\n" +
+            "   \"root-property\": \"root-property-value\",\n" +
+            "   \"root-property-null\": null,\n" +
+            "   \"children\": [\n" +
+            "      {\n" +
+            "         \"id\": 0,\n" +
+            "         \"name\": \"name-0\",\n" +
+            "         \"age\": 0\n" +
+            "      },\n" +
+            "      {\n" +
+            "         \"id\": 1,\n" +
+            "         \"name\": \"name-1\",\n" +
+            "         \"age\": null" +
+            "      },\n" +
+            "      {\n" +
+            "         \"id\": 3,\n" +
+            "         \"name\": \"name-3\"\n" +
+            "      }\n" +
+            "   ]\n" +
+            "}";
+
+
+    @Test(expected = PathNotFoundException.class)
+    public void not_defined_property_throws_PathNotFoundException () {
+         JsonPath.read(DOCUMENT, "$.children[2].age");
+    }
+
+    @Test
+    public void null_property_returns_null () {
+        Integer age = JsonPath.read(DOCUMENT, "$.children[1].age");
+        assertEquals(null, age);
+    }
+
+    @Test
+    public void the_age_of_all_with_age_defined() {
+        List<Integer> result = JsonPath.read(DOCUMENT, "$.children[*].age");
+
+        assertThat(result, Matchers.hasItems(0, null));
+    }
+    @Test
+    public void path2(){
+        System.out.println(JsonPath.read("{\"a\":[{\"b\":1,\"c\":2},{\"b\":5,\"c\":2}]}", "a[?(@.b==4)].c"));
+    }
+
+    public void path(){
+        System.out.println(JsonPath.read("{\"a\":[{\"b\":1,\"c\":2},{\"b\":5,\"c\":2}]}", "a[?(@.b==5)].d"));
+    }
+
+
+}