From b9f34edf74a3201f507a8efc17ffba46e20d961d Mon Sep 17 00:00:00 2001
From: Felix Schumacher <felix.schumacher@internetallee.de>
Date: Sat, 13 Nov 2021 15:46:37 +0100
Subject: [PATCH] Use default values for null values when extracting with
 JSONPostProcessor

---
 .../extractor/json/jsonpath/JSONManager.java  |  2 +-
 .../json/jsonpath/JSONPostProcessor.java      | 24 +++++++++++--------
 2 files changed, 15 insertions(+), 11 deletions(-)

diff --git a/src/components/src/main/java/org/apache/jmeter/extractor/json/jsonpath/JSONManager.java b/src/components/src/main/java/org/apache/jmeter/extractor/json/jsonpath/JSONManager.java
index f156f3d7c8..c3f3371e64 100644
--- a/src/components/src/main/java/org/apache/jmeter/extractor/json/jsonpath/JSONManager.java
+++ b/src/components/src/main/java/org/apache/jmeter/extractor/json/jsonpath/JSONManager.java
@@ -95,7 +95,7 @@ public class JSONManager {
         if (obj instanceof JSONArray) {
             return ((JSONArray)obj).toJSONString();
         }
-        return obj == null ? "" : obj.toString(); //$NON-NLS-1$
+        return obj == null ? null : obj.toString();
     }
 
 }
diff --git a/src/components/src/main/java/org/apache/jmeter/extractor/json/jsonpath/JSONPostProcessor.java b/src/components/src/main/java/org/apache/jmeter/extractor/json/jsonpath/JSONPostProcessor.java
index 3e7c5cf8be..2200827fe7 100644
--- a/src/components/src/main/java/org/apache/jmeter/extractor/json/jsonpath/JSONPostProcessor.java
+++ b/src/components/src/main/java/org/apache/jmeter/extractor/json/jsonpath/JSONPostProcessor.java
@@ -123,7 +123,7 @@ public class JSONPostProcessor
             handleListResult(vars, defaultValues, i, matchNumber, currentRefName, extractedValues);
         } else {
             // else just one value extracted
-            handleSingleResult(vars, matchNumber, currentRefName, extractedValues);
+            handleSingleResult(vars, defaultValues, matchNumber, currentRefName, extractedValues);
         }
         if (matchNumber != 0) {
             vars.put(currentRefName + REF_MATCH_NR, Integer.toString(extractedValues.size()));
@@ -142,10 +142,11 @@ public class JSONPostProcessor
         }
     }
 
-    private void handleSingleResult(JMeterVariables vars, final int matchNumber, String currentRefName,
-            List<Object> extractedValues) {
+    private void handleSingleResult(JMeterVariables vars, String[] defaultValues, final int matchNumber,
+            String currentRefName, List<Object> extractedValues) {
         String suffix = (matchNumber < 0) ? "_1" : "";
-        placeObjectIntoVars(vars, currentRefName + suffix, extractedValues, 0);
+        String defaultValue = defaultValues.length > 0 ? defaultValues[0] : "";
+        placeObjectIntoVars(vars, currentRefName + suffix, extractedValues, 0, defaultValue);
         if (matchNumber < 0 && getComputeConcatenation()) {
             vars.put(currentRefName + ALL_SUFFIX, vars.get(currentRefName + suffix));
         }
@@ -161,7 +162,8 @@ public class JSONPostProcessor
                             ? extractedValues.size() * 20
                             : 1);
             for (Object extractedObject : extractedValues) {
-                String extractedString = stringify(extractedObject);
+                String defaultValue = defaultValues.length > i ? defaultValues[i] : "";
+                String extractedString = StringUtils.defaultString(stringify(extractedObject), defaultValue);
                 vars.put(currentRefName + "_" + index,
                         extractedString); //$NON-NLS-1$
                 if (getComputeConcatenation()) {
@@ -180,8 +182,9 @@ public class JSONPostProcessor
             // Random extraction
             int matchSize = extractedValues.size();
             int matchNr = JMeterUtils.getRandomInt(matchSize);
+            String defaultValue = defaultValues.length > 0 ? defaultValues[0] : "";
             placeObjectIntoVars(vars, currentRefName,
-                    extractedValues, matchNr);
+                    extractedValues, matchNr, defaultValue);
             return;
         }
         // extract at position
@@ -193,7 +196,8 @@ public class JSONPostProcessor
             }
             vars.put(currentRefName, defaultValues[i]);
         } else {
-            placeObjectIntoVars(vars, currentRefName, extractedValues, matchNumber - 1);
+            String defaultValue = defaultValues.length > 0 ? defaultValues[0] : "";
+            placeObjectIntoVars(vars, currentRefName, extractedValues, matchNumber - 1, defaultValue);
         }
     }
 
@@ -245,13 +249,13 @@ public class JSONPostProcessor
     }
 
     private void placeObjectIntoVars(JMeterVariables vars, String currentRefName,
-            List<Object> extractedValues, int matchNr) {
+            List<Object> extractedValues, int matchNr, String defaultValue) {
         vars.put(currentRefName,
-                stringify(extractedValues.get(matchNr)));
+                StringUtils.defaultString(stringify(extractedValues.get(matchNr)), defaultValue));
     }
 
     private String stringify(Object obj) {
-        return obj == null ? "" : obj.toString(); //$NON-NLS-1$
+        return obj == null ? null : obj.toString();
     }
 
     public String getJsonPathExpressions() {
-- 
2.25.1