Troubleshooting .attr() Function In ArchiMate Scripting For Relationship Attributes

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When working with ArchiMate models using the Archi-Scripting-Plugin, manipulating relationship attributes is a common task. This article addresses a specific issue where the .attr() function does not seem to work as expected when trying to modify the "Name" attribute of relationships. We will explore the problem, the error encountered, and potential solutions, providing a comprehensive guide for users facing similar challenges. This guide aims to help you understand how to effectively manage relationship attributes within ArchiMate models using scripting.

Problem Description

The core issue revolves around the inability to write new values to the "Name" attribute of relationships using the .attr() function in the Archi-Scripting-Plugin. The user wants to read existing values of relationship "Name" attributes and modify them with new content. While the .prop() function successfully adds properties and values to the same relationships, using .attr() results in an error. Specifically, the error message indicates that the attr identifier is unknown, suggesting a potential problem with how the function is being called or with the function itself. Understanding the nuances of how these functions operate is crucial for effective ArchiMate model manipulation.

Error Encountered

The error message received when attempting to use .attr() is:

org.graalvm.polyglot.PolyglotException: TypeError: invokeMember (attr) on com.archimatetool.script.dom.model.ArchimateRelationshipProxy failed due to: Unknown identifier: attr
	at <js>.:anonymous(rel_test.ajs:14)
	at com.oracle.truffle.polyglot.PolyglotFunctionProxyHandler.invoke(PolyglotFunctionProxyHandler.java:151)
	at jdk.proxy1/jdk.proxy1.$Proxy40.accept(Unknown Source)
	at java.base/java.util.ArrayList.forEach(Unknown Source)
	at com.archimatetool.script.dom.model.EObjectProxyCollection.each(EObjectProxyCollection.java:363)

This error message indicates a TypeError, suggesting that the method attr is not recognized for the ArchimateRelationshipProxy object. This typically means that the function either does not exist or is not being called correctly within the scripting environment. The stack trace provides further details, pinpointing the exact line of code (rel_test.ajs:14) where the error occurs, helping in debugging the script.

Steps to Reproduce

To replicate the issue, follow these steps:

  1. Create a Test Model in Archi.
  2. Select the Default View.
  3. Load the first six steps from the provided script example (https://gist.github.com/FrancoisCoudeville/8acb82a7f9c1ca020bc8ea0f8ff04452#file-step-by-step-script-examples-v0-1-ajs) to populate the model with relationships. Alternatively, use any existing model that contains relationships.
  4. Select the default view.
  5. Run the attached script (rel_test.ajs).

In the script, the .prop() function works as expected, but the .attr() function fails with the aforementioned error. This consistent failure when using .attr() highlights a specific problem with this function in the context of relationship attributes.

Analyzing the Script and ArchiMate Scripting

To effectively troubleshoot this issue, a deeper dive into the ArchiMate scripting environment and the specific script being used is necessary. ArchiMate scripting allows users to automate model manipulation, query model elements, and perform various operations that would otherwise be manual and time-consuming. The Archi-Scripting-Plugin extends Archi’s capabilities by providing a JavaScript-based scripting environment. Understanding how this environment interacts with ArchiMate model elements is crucial for debugging scripting issues.

Understanding .attr() and .prop()

The key to resolving this issue lies in understanding the difference between .attr() and .prop(). In the Archi-Scripting-Plugin:

  • .attr(): This function is intended for accessing and modifying the core attributes of an ArchiMate element, such as its name, documentation, and type. Core attributes are intrinsic properties defined directly within the ArchiMate metamodel.
  • .prop(): This function is used for managing user-defined properties of an element. User-defined properties are additional pieces of information that can be attached to an element, beyond its core attributes. These properties are stored as key-value pairs and are useful for extending the ArchiMate metamodel with custom metadata.

The error message suggests that .attr() might not be the correct function to use for modifying the "Name" attribute in this context. It’s possible that the "Name" attribute, while seemingly a core attribute, is handled differently by the scripting engine or that there’s a misunderstanding in how the function should be applied.

Examining the Script

The provided script (rel_test.ajs) attempts to modify the "Name" attribute of relationships. To diagnose the issue, let’s consider a hypothetical snippet of what the script might look like:

// Sample script snippet
model.relationships.each(function(rel) {
  rel.prop("TestProperty", "TestValue"); // This works
  try {
    rel.attr("Name", "New Name"); // This fails
  } catch (e) {
    print(e); // Prints the error message
  }
});

This snippet iterates through all relationships in the model. For each relationship, it successfully adds a property using .prop(). However, when it attempts to use .attr() to modify the "Name" attribute, it encounters the TypeError. The try...catch block is used to capture the error and print it to the console, allowing for easier debugging.

Potential Solutions and Workarounds

Given the error and the understanding of .attr() and .prop(), several potential solutions and workarounds can be explored:

1. Using .name Property Directly

One possible solution is to directly access and modify the name property of the relationship object. In many scripting environments, object properties can be accessed directly using dot notation. For example:

model.relationships.each(function(rel) {
  rel.name = "New Name"; // Direct property access
});

This approach bypasses the .attr() function and directly sets the name property. If this works, it suggests that the name attribute is exposed as a direct property of the relationship object.

2. Using .setProperty() Method

Another approach is to use the .setProperty() method, which is a more generic way to set properties on EObjects in the Eclipse Modeling Framework (EMF), which ArchiMate is based on. The .setProperty() method takes the property name and the new value as arguments:

model.relationships.each(function(rel) {
  rel.setProperty("name", "New Name"); // Using setProperty
});

This method is more aligned with the underlying EMF framework and might be more reliable for setting attributes that are not directly exposed as properties.

3. Checking ArchiMate Version and Plugin Documentation

The ArchiMate metamodel and the Archi-Scripting-Plugin are subject to updates and changes. It’s possible that the behavior of .attr() has changed in a specific version or that there are specific requirements for using it. Therefore, it’s crucial to consult the documentation for the specific version of Archi and the Archi-Scripting-Plugin being used.

The documentation might provide insights into the correct way to use .attr() or suggest alternative methods for modifying attributes. It might also highlight any known issues or limitations with the function.

4. Debugging with print() Statements

Debugging scripts often involves adding print() statements to inspect the values of variables and the state of objects. In this case, printing the relationship object and its properties can provide valuable information:

model.relationships.each(function(rel) {
  print(rel); // Print the relationship object
  print(rel.name); // Print the current name
  try {
    rel.attr("Name", "New Name");
  } catch (e) {
    print(e);
  }
});

By printing the relationship object, you can see its structure and the properties it exposes. Printing the current name confirms whether the name property is accessible. This debugging technique helps in understanding how the object is represented in the scripting environment and what properties are available for manipulation.

5. Verifying ArchiMate Model Structure

Sometimes, issues can arise from the structure of the ArchiMate model itself. Corrupted or incorrectly defined model elements can lead to unexpected behavior. Verifying the model structure and ensuring that the relationships are correctly defined can help in identifying potential problems.

This might involve manually inspecting the model in Archi, checking for any inconsistencies or errors. It could also involve using scripting to validate the model structure programmatically.

Practical Implementation and Examples

To illustrate the potential solutions, let’s look at some practical examples.

Example 1: Using Direct Property Access

// Script to modify relationship names using direct property access
var model = Archi.model;
model.relationships.each(function(rel) {
  var oldName = rel.name;
  rel.name = oldName + " (Modified)";
  print("Modified relationship name: " + rel.name);
});

This script iterates through all relationships in the model, retrieves the current name, appends " (Modified)" to it, and sets the new name using direct property access. The print() statement confirms the modification.

Example 2: Using .setProperty()

// Script to modify relationship names using setProperty()
var model = Archi.model;
model.relationships.each(function(rel) {
  var oldName = rel.getProperty("name");
  rel.setProperty("name", oldName + " (Modified)");
  print("Modified relationship name: " + rel.getProperty("name"));
});

This script uses the .setProperty() method to achieve the same result. It retrieves the current name using getProperty(), modifies it, and sets the new name using setProperty(). This approach is more aligned with the EMF framework and can be more robust.

Example 3: Debugging Script

// Debugging script to inspect relationship objects
var model = Archi.model;
model.relationships.each(function(rel) {
  print("Relationship: " + rel);
  print("Name: " + rel.name);
  try {
    rel.attr("Name", rel.name + " (Attempted)");
  } catch (e) {
    print("Error: " + e);
  }
});

This script prints the relationship object and its name, then attempts to use .attr() to modify the name. The try...catch block captures any errors and prints them, providing valuable debugging information.

Conclusion

Troubleshooting scripting issues in ArchiMate models requires a systematic approach. Understanding the specific functions and methods available, the underlying metamodel, and the scripting environment is crucial for identifying and resolving problems. In the case of the .attr() function not working for relationship names, alternative approaches such as direct property access or using .setProperty() can provide effective solutions.

By following the steps outlined in this article, users can diagnose and resolve similar issues, ensuring they can effectively manipulate ArchiMate models using scripting. Remember to consult the documentation, debug with print() statements, and verify the model structure to achieve the desired results. This comprehensive guide aims to empower you to overcome challenges and harness the full potential of ArchiMate scripting.