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In the previous post, JADEx introduced a new feature ~~Immutability~~.
Through community feedback, several confusions and limitations were identified.
In v0.42, we have addressed these issues and improved the feature. This post explains the key improvements and new additions in this release.
Improvements
~~apply immutability~~ -> apply readonly
- The previous term (
Immutability) caused misunderstandings. - Community feedback revealed that “Immutable” was interpreted differently by different developers, either as Deeply Immutable or Shallowly Immutable.
- In v0.42, we replaced it with
readonly. - Meaning: clearly indicates final by default, preventing reassignment of variables.
Expanded Scope of final keyword: now includes method parameters
- v0.41: final was applied only to fields + local variables
- v0.42: final is applied to fields + local variables + method parameters
- Method parameters are now readonly by default, preventing accidental reassignment inside methods.
Example Code
JADEx Source Code
package jadex.example;
apply readonly;
public class Readonly {
private int capacity = 2; // readonly
private String? msg = "readonly"; // readonly
private int uninitializedCapacity; // error (uninitialized readonly)
private String uninitializedMsg; // error (uninitialized readonly)
private mutable String? mutableMsg = "mutable"; // mutable
public static void printMessages(String? mutableParam, String? readonlyParam) {
mutableParam = "try to change"; // error
readonlyParam = "try to change"; // error
System.out.println("mutableParam: " + mutableParam);
System.out.println("readonlyParam: " + readonlyParam);
}
public static void main(String[] args) {
var readonly = new Readonly();
String? mutableMsg = "changed mutable";
readonly.capacity = 10; // error
readonly.msg = "new readonly"; // error
readonly.mutableMsg = mutableMsg;
printMessages(readonly.msg, mutableMsg);
System.out.println("mutableMsg: " + readonly.mutableMsg);
System.out.println("capacity: " + readonly.capacity);
System.out.println("msg: " + readonly.msg);
}
}
Generated Java Code
package jadex.example;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;
import jadex.runtime.SafeAccess;
//apply readonly;
@NullMarked
public class Readonly {
private final int capacity = 2; // readonly
private final @Nullable String msg = "readonly"; // readonly
private final int uninitializedCapacity; // error (uninitilaized readonly)
private final String uninitializedMsg; // error (uninitilaized readonly)
private @Nullable String mutableMsg = "mutable"; // mutable
public static void printMessages(final @Nullable String mutableParam, final @Nullable String readonlyParam) {
mutableParam = "try to change"; //error
readonlyParam = "try to change"; //error
System.out.println("mutableParam: " + mutableParam);
System.out.println("readonlyParam: " + readonlyParam);
}
public static void main(final String[] args) {
final var readonly = new Readonly();
final @Nullable String mutableMsg = "changed mutable";
readonly.capacity = 10; //error
readonly.msg = "new readonly"; //error
readonly.mutableMsg = mutableMsg;
printMessages(readonly.msg, mutableMsg);
System.out.println("mutableMsg: " + readonly.mutableMsg);
System.out.println("capacity: " + readonly.capacity);
System.out.println("msg: " + readonly.msg);
}
}
New Additions
JSpecify @NullMarked Annotation Support
- All Java code generated by JADEx now includes the
@NullMarkedannotation. - This improves Null-Safety along with readonly enforcement.
This feature is available starting from JADEx v0.42. Since the IntelliJ Plugin for JADEx v0.42 has not yet been published on the JetBrains Marketplace, if you wish to try it, please download the JADEx IntelliJ Plugin from the link below and install it manually.
We highly welcome your feedback on JADEx.
Thank you.
