JsonProvider returns constant value to signal undefined instead of throwing exception.

json-path/src/main/java/com/jayway/jsonpath/internal/spi/compiler/PathToken.java

@@ -4,6 +4,7 @@ import com.jayway.jsonpath.InvalidPathException;
 import com.jayway.jsonpath.Option;
 import com.jayway.jsonpath.PathNotFoundException;
 import com.jayway.jsonpath.internal.Utils;
+import com.jayway.jsonpath.spi.json.JsonProvider;
 
 import java.util.List;
 
@@ -67,7 +68,11 @@ abstract class PathToken {
     }
 
     private Object readObjectProperty(String property, Object model, EvaluationContextImpl ctx) {
-        return ctx.jsonProvider().getMapValue(model, property, ctx.options().contains(Option.THROW_ON_MISSING_PROPERTY));
+        Object val = ctx.jsonProvider().getMapValue(model, property, ctx.options().contains(Option.THROW_ON_MISSING_PROPERTY));
+        if(val == JsonProvider.UNDEFINED){
+            throw new PathNotFoundException("Property ['" + property + "'] not found in the current context" );
+        }
+        return val;
     }
 
     void handleArrayIndex(int index, String currentPath, Object json, EvaluationContextImpl ctx) {

json-path/src/main/java/com/jayway/jsonpath/internal/spi/json/AbstractJsonProvider.java

@@ -14,7 +14,6 @@
  */
 package com.jayway.jsonpath.internal.spi.json;
 
-import com.jayway.jsonpath.PathNotFoundException;
 import com.jayway.jsonpath.internal.Utils;
 import com.jayway.jsonpath.spi.json.JsonProvider;
 
@@ -79,13 +78,13 @@ public abstract class AbstractJsonProvider implements JsonProvider {
      *
      * @param obj a map
      * @param key property key
-     * @param throwOnMissing if true a PathNotFoundException is thrown if property is missing
+     * @param signalUndefined if true the constant {@link com.jayway.jsonpath.spi.json.JsonProvider#UNDEFINED} is returned for missing properties
      * @return the map entry
      */
-    public Object getMapValue(Object obj, String key, boolean throwOnMissing){
+    public Object getMapValue(Object obj, String key, boolean signalUndefined){
         Map m = (Map) obj;
-        if(!m.containsKey(key) && throwOnMissing){
-            throw new PathNotFoundException("Property ['" + key + "'] not found in the current context" );
+        if(!m.containsKey(key) && signalUndefined){
+            return JsonProvider.UNDEFINED;
         } else {
             return m.get(key);
         }

json-path/src/main/java/com/jayway/jsonpath/spi/json/JsonProvider.java

@@ -19,10 +19,11 @@ import com.jayway.jsonpath.InvalidJsonException;
 import java.io.InputStream;
 import java.io.Reader;
 import java.util.Collection;
-import java.util.List;
 
 public interface JsonProvider {
 
+    static final Object UNDEFINED = new Object();
+
     Mode getMode();
 
     Object parse(String json) throws InvalidJsonException;
@@ -114,10 +115,10 @@ public interface JsonProvider {
      *
      * @param obj a map
      * @param key property key
-     * @param throwOnMissing if true a PathNotFoundException is thrown if property is not defined
+     * @param signalUndefined if true the constant {@link com.jayway.jsonpath.spi.json.JsonProvider#UNDEFINED} is returned for missing properties
      * @return the map entry
      */
-    Object getMapValue(Object obj, String key, boolean throwOnMissing);
+    Object getMapValue(Object obj, String key, boolean signalUndefined);
 
     /**
      * Sets a value in an object or array