Allow JsonNodeELResolver to invoke get and path with a long index (#3996)

Author: rssap

modules/flowable-engine-common/src/main/java/org/flowable/common/engine/impl/el/JsonNodeELResolver.java

@@ -39,14 +39,14 @@ public class JsonNodeELResolver extends ELResolver {
     private final boolean readOnly;
 
     /**
-     * Creates a new read/write BeanELResolver.
+     * Creates a new read/write JsonNodeELResolver.
      */
     public JsonNodeELResolver() {
         this(false);
     }
 
     /**
-     * Creates a new BeanELResolver whose read-only status is determined by the given parameter.
+     * Creates a new JsonNodeELResolver whose read-only status is determined by the given parameter.
      */
     public JsonNodeELResolver(boolean readOnly) {
         this.readOnly = readOnly;
@@ -257,6 +257,38 @@ public boolean isReadOnly(ELContext context, Object base, Object property) {
         }
         return readOnly;
     }
+    
+    @Override
+	public Object invoke(ELContext context, Object base, Object method, Class<?>[] paramTypes, Object[] params) {
+        if (!isResolvable(base)) {
+            return null;
+        }
+        if (method == null) {
+            return null;
+        }
+        if (params.length != 1) {
+            return null;
+        }
+        Object param = params[0];
+        if (!(param instanceof Long)) {
+            return null;
+        }
+
+        int index = ((Long) param).intValue();
+        String methodName = method.toString();
+        JsonNode node = (JsonNode) base;
+        if (methodName.equals("path")) {
+            JsonNode valueNode = node.path(index);
+            context.setPropertyResolved(true);
+            return valueNode;
+        } else if (methodName.equals("get")) {
+            JsonNode valueNode = node.get(index);
+            context.setPropertyResolved(true);
+            return valueNode;
+        }
+
+        return null;
+	}
 
     /**
      * If the base object is a map, attempts to set the value associated with the given key, as specified by the property argument. If the base is a Map, the propertyResolved property of the ELContext

modules/flowable-engine/src/test/java/org/flowable/engine/test/el/ExpressionManagerTest.java

@@ -32,6 +32,7 @@
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.ValueSource;
 
+import com.fasterxml.jackson.databind.node.ArrayNode;
 import com.fasterxml.jackson.databind.node.ObjectNode;
 
 /**
@@ -275,6 +276,66 @@ public void testInvokeIntegerMethodWithNullParameter() {
         assertThat(value).isNull();
     }
 
+    @Test
+    @Deployment(resources = "org/flowable/engine/test/api/runtime/oneTaskProcess.bpmn20.xml")
+    public void testInvokeOnArrayNode() {
+        Map<String, Object> vars = new HashMap<>();
+        ArrayNode arrayNode = processEngineConfiguration.getObjectMapper().createArrayNode();
+        arrayNode.add("firstValue");
+        arrayNode.add("secondValue");
+        arrayNode.add(42);
+
+        vars.put("array", arrayNode);
+        ProcessInstance processInstance = runtimeService.startProcessInstanceByKey("oneTaskProcess", vars);
+
+        assertThat(getExpressionValue("${array.get(0).isTextual()}", processInstance)).isEqualTo(true);
+        assertThat(getExpressionValue("${array.get(0).textValue()}", processInstance)).isEqualTo("firstValue");
+        assertThat(getExpressionValue("${array.get(0).isNumber()}", processInstance)).isEqualTo(false);
+
+        assertThat(getExpressionValue("${array.get(2).isNumber()}", processInstance)).isEqualTo(true);
+        assertThat(getExpressionValue("${array.get(2).asInt()}", processInstance)).isEqualTo(42);
+        assertThat(getExpressionValue("${array.get(2).asLong()}", processInstance)).isEqualTo(42L);
+
+        assertThat(getExpressionValue("${array.get(1).textValue()}", processInstance)).isEqualTo("secondValue");
+        assertThat(getExpressionValue("${array.get(1).asLong(123)}", processInstance)).isEqualTo(123L);
+
+        assertThat(getExpressionValue("${array.get(3)}", processInstance)).isNull();
+        assertThat(getExpressionValue("${array.path(3).isMissingNode()}", processInstance)).isEqualTo(true);
+    }
+
+    @Test
+    @Deployment(resources = "org/flowable/engine/test/api/runtime/oneTaskProcess.bpmn20.xml")
+    public void testInvokeOnObjectNode() {
+        Map<String, Object> vars = new HashMap<>();
+        ObjectNode objectNode = processEngineConfiguration.getObjectMapper().createObjectNode();
+        objectNode.put("firstAttribute", "foo");
+        objectNode.put("secondAttribute", "bar");
+        objectNode.put("thirdAttribute", 42);
+
+        vars.put("object", objectNode);
+        ProcessInstance processInstance = runtimeService.startProcessInstanceByKey("oneTaskProcess", vars);
+
+        assertThat(getExpressionValue("${object.get(\"firstAttribute\").isTextual()}", processInstance)).isEqualTo(true);
+        assertThat(getExpressionValue("${object.get(\"firstAttribute\").textValue()}", processInstance)).isEqualTo("foo");
+        assertThat(getExpressionValue("${object.get(\"firstAttribute\").isNumber()}", processInstance)).isEqualTo(false);
+
+        assertThat(getExpressionValue("${object.get(\"thirdAttribute\").isNumber()}", processInstance)).isEqualTo(true);
+        assertThat(getExpressionValue("${object.get(\"thirdAttribute\").asInt()}", processInstance)).isEqualTo(42);
+        assertThat(getExpressionValue("${object.get(\"thirdAttribute\").asLong()}", processInstance)).isEqualTo(42L);
+
+        assertThat(getExpressionValue("${object.get(\"secondAttribute\").textValue()}", processInstance)).isEqualTo("bar");
+        assertThat(getExpressionValue("${object.get(\"secondAttribute\").asLong(123)}", processInstance)).isEqualTo(123L);
+
+        assertThat(getExpressionValue("${object.get(\"dummyAttribute\")}", processInstance)).isNull();
+        assertThat(getExpressionValue("${object.path(\"dummyAttribute\").isMissingNode()}", processInstance)).isEqualTo(true);
+    }
+  
+    private Object getExpressionValue(String expressionStr, ProcessInstance processInstance) {
+        Expression expression = this.processEngineConfiguration.getExpressionManager().createExpression(expressionStr);
+        return managementService.executeCommand(commandContext ->
+            expression.getValue((ExecutionEntity) runtimeService.createProcessInstanceQuery().processInstanceId(processInstance.getId()).includeProcessVariables().singleResult()));
+    }
+
     @ParameterizedTest
     @Deployment(resources = "org/flowable/engine/test/api/runtime/oneTaskProcess.bpmn20.xml")
     @ValueSource(strings = { "", "flowable" })