added manual expression detection

src/main/java/com/inteligr8/activiti/mq/MqServiceTask.java

@@ -70,26 +70,62 @@ public class MqServiceTask {
 	
 	@SuppressWarnings("unchecked")
 	protected <T> T getFieldValueFromModel(String fieldName, Class<T> type, VariableScope varscope, boolean forceExpressionProcessing) {
+		Object value = this.getFieldValueFromModel(fieldName, varscope, forceExpressionProcessing);
+		
+		if (value == null) {
+			return null;
+		} else if (String.class.isAssignableFrom(type)) {
+			if (value instanceof String) {
+				return (T) value;
+			} else {
+				return (T) value.toString();
+			}
+		} else {
+			try {
+				Method method = type.getMethod("valueOf", value.getClass());
+				return (T) method.invoke(null, value);
+			} catch (NoSuchMethodException | InvocationTargetException | IllegalAccessException e) {
+				String strvalue;
+				if (value instanceof String) {
+					strvalue = (String) value;
+				} else {
+					strvalue = value.toString();
+				}
+				
+				try {
+					Method method = type.getMethod("valueOf", String.class);
+					return (T) method.invoke(null, strvalue);
+				} catch (NoSuchMethodException | InvocationTargetException | IllegalAccessException e2) {
+					throw new IllegalArgumentException("The target type '" + type + "' has no 'valueOf' method for String or type: " + value.getClass());
+				}
+			}
+		}
+	}
+	
+	protected Object getFieldValueFromModel(String fieldName, VariableScope varscope, boolean forceExpressionProcessing) {
 		FieldExtension field = this.fieldMap.get(fieldName);
 		if (field == null) {
 			return null;
 		} else if (field.getExpression() != null && field.getExpression().length() > 0) {
+			this.logger.trace("Field value is recognized as an expression by the Activity framework: {}: {}", fieldName, field.getExpression());
 			ExpressionManager exprman = Context.getProcessEngineConfiguration().getExpressionManager();
 			Expression expr = exprman.createExpression(field.getExpression());
-			return (T) expr.getValue(varscope);
+			return expr.getValue(varscope);
+		} else if (field.getStringValue() == null) {
+			this.logger.trace("Field value is null: {}", fieldName);
+			return null;
 		} else if (forceExpressionProcessing) {
+			this.logger.trace("Field value will be processed as potentially having expression(s): {}", fieldName);
 			ExpressionManager exprman = Context.getProcessEngineConfiguration().getExpressionManager();
 			Expression expr = exprman.createExpression(field.getStringValue());
-			return (T) expr.getValue(varscope);
+			return expr.getValue(varscope);
-		} else if (String.class.isAssignableFrom(type)) {
+		} else if (field.getStringValue().startsWith("${") && field.getStringValue().endsWith("}")) {
-			return (T) field.getStringValue();
+			this.logger.trace("Field value is recognized as an expression by the MQ extension: {}: {}", fieldName, field.getStringValue());
+			ExpressionManager exprman = Context.getProcessEngineConfiguration().getExpressionManager();
+			Expression expr = exprman.createExpression(field.getStringValue());
+			return expr.getValue(varscope);
 		} else {
-			try {
+			return field.getStringValue();
-				Method method = type.getMethod("valueOf", String.class);
-				return (T) method.invoke(null, field.getStringValue());
-			} catch (NoSuchMethodException | InvocationTargetException | IllegalAccessException e) {
-				throw new IllegalArgumentException(e);
-			}
 		}
 	}