Add number type conversion validation to ensure proper casting between numeric types

[mcruzdev]

Changes

• Implement convertNumber method in AbstractWorkflowModel to handle conversions between numeric types
• Fix issue where asNumber() returned incompatible Number types without proper casting
• Ensure type safety when converting workflow model outputs to specific numeric types

Closes #1200

[Copilot]

Pull request overview

This PR adds a convertNumber private method to AbstractWorkflowModel to properly dispatch numeric type conversions when as(Class<T>) is called with a Number-derived class (previously returning whatever asNumber() produced, which could cause a ClassCastException at the call site). It also adds a comprehensive suite of integration tests covering several primitive wrapper conversions (Long↔Integer, Double↔Integer, Float↔Double, Short↔Integer, Byte↔Integer).

Changes:

• AbstractWorkflowModel.java: Replace the raw asNumber() call with asNumber().map(num -> convertNumber(num, clazz)), and add the convertNumber dispatch method.
• WorkflowNumberConversionTest.java: New integration test class exercising seven conversion scenarios.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
impl/core/src/main/java/io/serverlessworkflow/impl/AbstractWorkflowModel.java	Adds convertNumber method and wires it into as() for Number-typed requests
impl/test/src/test/java/io/serverlessworkflow/impl/test/WorkflowNumberConversionTest.java	Integration tests for numeric type conversions across multiple primitive wrapper types

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 5 comments.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[fjtirado]

@mcruzdev Great work Matheus
I think you can apply copilot suggestions before merge

[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated no new comments.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

The workflow name "doubleToInt" in the double_to_big_decimal_conversion test is incorrect — it reuses the same name as the double_to_integer_conversion test. The name should reflect the actual conversion being tested (e.g., "doubleToBigDecimal"). While each test creates its own WorkflowApplication instance so there's no runtime collision, using a misleading workflow name makes the test harder to understand and debug.

Suggested change

	FuncWorkflowBuilder.workflow("doubleToInt")
	FuncWorkflowBuilder.workflow("doubleToBigDecimal")

[Copilot]

The BigInteger case is incorrectly grouped with Integer in the condition at line 74. When targetNumberClass == BigInteger.class, the code calls num.intValue() which returns a primitive int (autoboxed to Integer), and then attempts targetNumberClass.cast(someInteger) where targetNumberClass == BigInteger.class. This will always throw a ClassCastException because an Integer cannot be cast to BigInteger.

The fix should use BigInteger.valueOf(num.longValue()) instead, and this case should be separated from the Integer branch. For example:

• The BigInteger branch should call BigInteger.valueOf(num.longValue()) and then cast to targetNumberClass.

Suggested change

	if (targetNumberClass == Integer.class || targetNumberClass == BigInteger.class) {
	return Optional.of(targetNumberClass.cast(num.intValue()));
	if (targetNumberClass == Integer.class) {
	return Optional.of(targetNumberClass.cast(num.intValue()));
	} else if (targetNumberClass == BigInteger.class) {
	return Optional.of(targetNumberClass.cast(BigInteger.valueOf(num.longValue())));

[Copilot]

The BigDecimal case is incorrectly grouped with Double in the condition at line 78. When targetNumberClass == BigDecimal.class, the code calls num.doubleValue() which returns a primitive double (autoboxed to Double), and then attempts targetNumberClass.cast(someDouble) where targetNumberClass == BigDecimal.class. This will always throw a ClassCastException because a Double cannot be cast to BigDecimal.

The fix should use BigDecimal.valueOf(num.doubleValue()) instead, and this case should be separated from the Double branch. For example:

• The BigDecimal branch should call BigDecimal.valueOf(num.doubleValue()) and then cast to targetNumberClass.

Suggested change

	} else if (targetNumberClass == Double.class || targetNumberClass == BigDecimal.class) {
	return Optional.of(targetNumberClass.cast(num.doubleValue()));
	} else if (targetNumberClass == Double.class) {
	return Optional.of(targetNumberClass.cast(num.doubleValue()));
	} else if (targetNumberClass == BigDecimal.class) {
	return Optional.of(targetNumberClass.cast(BigDecimal.valueOf(num.doubleValue())));