How do I install the Openrocket Jpype Interop skill?

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Is Openrocket Jpype Interop free to use?

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Who published Openrocket Jpype Interop?

rocketpy-team (@rocketpy-team) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Openrocket Jpype Interop by rocketpy-team

Name: Openrocket Jpype Interop
Author: rocketpy-team

Openrocket Jpype Interop

Work with the OpenRocket Java library through JPype — start/stop the JVM, load .ork documents, traverse the rocket component tree, and read data from both the XML (BeautifulSoup) and the live Java object. Use when touching openrocket_runtime.py, open_rocket_wrangler.py, ork_extractor.py, the JVM/Java setup, or anything that calls into net.sf.openrocket / info.openrocket.

File contents

OpenRocket ↔ JPype interop

The two-source model

ork_extractor(bs, filepath, output_folder, ork) reads from two sources simultaneously — always know which one a given value comes from:

bs — a BeautifulSoup tree of the .ork XML (_helpers.parse_ork_file). Source of the simulation datapoints and most numeric parameters. Access via bs.find(...), bs.find_all("datapoint"), and bs.find("databranch").attrs["types"] (the comma-joined column labels).
ork — the live Java OpenRocket document (OpenRocketSession.load_doc). Source of geometry and component positions that the XML doesn't expose cleanly. Reached via ork.getRocket() and traversed in components/open_rocket_wrangler.py.

When adding an extractor, prefer bs for scalar/sim data and only reach into ork when the value requires walking the component hierarchy.

The JVM lifecycle (read before changing session code)

JPype is pinned jpype1<1.5, which cannot restart a JVM in one process. Consequences:

OpenRocketSession.__exit__ must not call jpype.shutdownJVM(). It only disposes AWT windows. The JVM is cleaned up by JPype's atexit hook.
Never open a second OpenRocketSession in a test. tests/conftest.py opens one session at import time and caches every example's settings in _cached_settings.
To use the session: with OpenRocketSession(jar_path, log_level="OFF") as s: doc = s.load_doc(path).

Package namespaces

OpenRocket moved from net.sf.openrocket (legacy, ≤ ~22) to info.openrocket (modern). OpenRocketSession._resolve_packages() tries legacy first, then modern, returning (core, swing). If you support a new jar and a symbol is missing, extend that method rather than hard-coding a namespace anywhere else.

Java version compatibility

ensure_java_compatibility(jar_path) picks the minimum Java: OpenRocket 23+ → Java 17, else Java 8. On Windows it auto-discovers a JDK under C:/Program Files/Java (and Adoptium / AdoptOpenJDK) and sets JAVA_HOME/PATH. On other OSes it only warns — the user must provide a compatible JVM. Jar version is parsed from the filename by _jar_version_tuple.

Traversing the component tree

open_rocket_wrangler.py helpers: is_sub_component(ork) (depth > 1 from root), parent_is_a_stage(ork) (parent class is Stage/AxialStage), and process_elements_position(...) which builds the position map used by fins, nose cone, transitions, and rail buttons. Component Java classes are identified by ork.getClass().getSimpleName().

Gotchas

Java calls raise jpype.JException (plus AttributeError/TypeError/RuntimeError when internals change between versions). Catch these narrowly — see _block_loader.
The .ork file is a zip containing rocket.ork (XML). extract_ork_from_zip handles both the zipped and already-extracted cases (it catches BadZipFile).

---name: openrocket-jpype-interopdescription: Work with the OpenRocket Java library through JPype — start/stop the JVM, load .ork documents, traverse the rocket component tree, and read data from both the XML (BeautifulSoup) and the live Java object. Use when touching openrocket_runtime.py, open_rocket_wrangler.py, ork_extractor.py, the JVM/Java setup, or anything that calls into net.sf.openrocket / info.openrocket.---# OpenRocket ↔ JPype interop## The two-source model`ork_extractor(bs, filepath, output_folder, ork)` reads from **two sourcessimultaneously** — always know which one a given value comes from:- `bs` — a `BeautifulSoup` tree of the `.ork` XML (`_helpers.parse_ork_file`). Source of the simulation **datapoints** and most numeric parameters. Access via `bs.find(...)`, `bs.find_all("datapoint")`, and `bs.find("databranch").attrs["types"]` (the comma-joined column labels).- `ork` — the **live Java OpenRocket document** (`OpenRocketSession.load_doc`). Source of **geometry and component positions** that the XML doesn't expose cleanly. Reached via `ork.getRocket()` and traversed in `components/open_rocket_wrangler.py`.When adding an extractor, prefer `bs` for scalar/sim data and only reach into `ork` when thevalue requires walking the component hierarchy.## The JVM lifecycle (read before changing session code)JPype is pinned **`jpype1<1.5`**, which **cannot restart a JVM in one process**. Consequences:- `OpenRocketSession.__exit__` must **not** call `jpype.shutdownJVM()`. It only disposes AWT windows. The JVM is cleaned up by JPype's atexit hook.- Never open a second `OpenRocketSession` in a test. `tests/conftest.py` opens **one** session at import time and caches every example's settings in `_cached_settings`.- To use the session: `with OpenRocketSession(jar_path, log_level="OFF") as s: doc = s.load_doc(path)`.## Package namespacesOpenRocket moved from `net.sf.openrocket` (legacy, ≤ ~22) to `info.openrocket` (modern).`OpenRocketSession._resolve_packages()` tries legacy first, then modern, returning`(core, swing)`. If you support a new jar and a symbol is missing, extend that method ratherthan hard-coding a namespace anywhere else.## Java version compatibility`ensure_java_compatibility(jar_path)` picks the minimum Java: OpenRocket 23+ → Java 17,else Java 8. On Windows it auto-discovers a JDK under `C:/Program Files/Java` (and Adoptium/ AdoptOpenJDK) and sets `JAVA_HOME`/`PATH`. On other OSes it only warns — the user mustprovide a compatible JVM. Jar version is parsed from the filename by `_jar_version_tuple`.## Traversing the component tree`open_rocket_wrangler.py` helpers: `is_sub_component(ork)` (depth > 1 from root),`parent_is_a_stage(ork)` (parent class is `Stage`/`AxialStage`), and`process_elements_position(...)` which builds the position map used by fins, nose cone,transitions, and rail buttons. Component Java classes are identified by`ork.getClass().getSimpleName()`.## Gotchas- Java calls raise `jpype.JException` (plus `AttributeError`/`TypeError`/`RuntimeError` when internals change between versions). Catch these narrowly — see `_block_loader`.- The `.ork` file is a **zip** containing `rocket.ork` (XML). `extract_ork_from_zip` handles both the zipped and already-extracted cases (it catches `BadZipFile`).

Frequently asked questions