Java Object Serialization
Ergonomic java.io.Serializable
parsing for JavaScript and TypeScript projects.
Example
import { ObjectInputStream } from "java-object-serialization";
class List {
value: number = 0;
next: List | null = null;
}
ObjectInputStream.RegisterObjectClass(List, "List", "7622494193198739048");
const data = "rO0ABXNyAARMaXN0aciKFUAWrmgCAAJJAAV2YWx1ZUwABG5leHR0AAZMTGlzdDt4cAAAABFzcQB+AAAAAAATcHEAfgAD";
const serialized = Buffer.from(data, "base64");
const stream = new ObjectInputStream(serialized);
const list1 = stream.readObject();
const list2 = stream.readObject();
The above code deserializes the example given in the Java Object Serialization specification:
class List implements java.io.Serializable {
int value;
List next;
public static void main(String[] args) {
List list1 = new List();
List list2 = new List();
list1.value = 17;
list1.next = list2;
list2.value = 19;
list2.next = null;
ByteArrayOutputStream o = new ByteArrayOutputStream();
ObjectOutputStream out = new ObjectOutputStream(o);
out.writeObject(list1);
out.writeObject(list2);
out.flush();
...
}
}
There is a JavaSerializable
interface that can be implemented to customize the deserialization behaviour for classes:
interface JavaSerializable {
readObject?(stream: ObjectInputStream): void
readResolve?(): any
}
readObject
needs to be implemented for classes that were serialized with a writeObject
implementation. As with the Java interface the methods on the passed in ObjectInputStream
can be used to read data related to the class, including the defaultReadObject
method to read and populate the standard serialized fields.
readResolve
can be implemented to return an alternative value when deserializing, this can be useful to e.g. return a JavaScript array for java.util.ArrayList
:
class ArrayList implements JavaSerializable {
size: number = 0;
elements: any[] = [];
readObject(stream: ObjectInputStream): void {
// Read in size, and any hidden stuff
stream.defaultReadObject();
// Read in capacity
stream.readInt(); // ignored
for (let i = 0; i < this.size; ++i) {
this.elements.push(stream.readObject());
}
}
readResolve(): any {
return this.elements;
}
}
JavaObjectStream.RegisterObjectClass(ArrayList, "java.util.ArrayList", "8683452581122892189");
Status
The full Java Object Serialization specification isn't covered, and the API surface isn't stable, but it is usable for parsing real data.