# Mograsim Development Environment
_Mograsim Development Documentation Version 0.3 --- 2019-09-27_
A short guide to the Mograsim Maven Tycho configuration and Maven Tycho in general,
as well as some information on Eclipse Plugin Development and OSGi.
## Maven Tycho
[Maven Tycho](https://www.eclipse.org/tycho/sitedocs/index.html) is a plugin for
[Maven](http://maven.apache.org) that allows building Eclipse and OSGi Projects comfortably
and automatically using Maven.
Useful links:
- [eclipse.org/tycho](https://www.eclipse.org/tycho/)
- [wiki.eclipse.org/Category:Tycho](https://wiki.eclipse.org/Category:Tycho)
- [vogella.com/tutorials/EclipseTycho](https://www.vogella.com/tutorials/EclipseTycho/article.html)
- [eclipse.org/tycho/sitedocs](https://www.eclipse.org/tycho/sitedocs/index.html)
- [Tycho pomless sources](https://git.eclipse.org/c/tycho/org.eclipse.tycho.extras.git/tree/tycho-pomless/src/main/java/org/eclipse/tycho/pomless)
(see *Mapping for naming and other conventions, TychoAggregatorMapping for folders)
## OSGi
OSGi is a module system for Java (completely unrelated to the Java 9 Jigsaw module
system) that allows detailed control over modules, dependencies, versions and more.
The file associated with OSGi here is a specific MANIFEST.MF in the META-INF directory
of each project.
Roughly, an OSGi bundle has:
- a **symbolic name** that acts as an identifier, therefore it should be unique and
must not be changed, otherwise it a large portion of the configuration would break.
Never change that field after distribution.
- a **bundle name** and **bundle vendor**; this is only for the users and developers
and is not constrained in any way. You can change that, but it should be consistent
across all Mograsim modules. Both can be externalized to
- a **bundle version** that denotes current the version of the bundle. The `qualifier`
is replaced during the build process with a timestamp of the format `YYYYMMDDhhmmss`.
The version itself can be set using the maven tycho version plugin, which replaces
not only the maven versions, but all (equivalent) versions in the MANIFEST as well.
- a **bundle required execution environment** (abbr. BREE) where the bundle's *minimal*
JDK version is set. This is also the one eclipse uses and displays as JRE System
Library in the Eclipse projects.
This should be the same as the one the target
definition used for the build and the same that maven is run with ( -> check the
Run Configuration)
## Eclipse Plugins
- Short explanation of the different names and terms used in Eclipse Plugin Dev,
and short introduction to the different mechanisms used.
## Mograsim Structure
The tree of Mograsim projects:
- `plugins` - _This contains all bundles/plugins that provide functionality to Mograsim_
- **net.mograsim.logic.core**
The core logic for pure simulation. This contains
the most important low-level logic circuits and gates and defines how that
logic gets simulated. The underlying system for simulation in Mograsim is an
event based approach (see `Timeline`), using VHDL-like logic defined in `Bit`
and `BitVector`. More complex ciruits are build out of `Wire`s connecting `Component`s.
- **net.mograsim.logic.model**
The model describes how that core logic is
displayed and arranged, and allows (de-)serialization to JSON. The core logic
model gets generated based on this. Every basic net.mograsim.logic.core Component
has a model equivalent here that represents it in the GUI and persisted state
(JSON).
- **net.mograsim.logic.model.editor**
This bundle contains a standalone
SWT-based editor to edit Mograsim JSON-models in a comfortable way. It can
be used to create a new `SubmodelComponent` by arranging existing ones to a
new component. Note that editing and simulation are entirely different processes
in Mograsim, the editor cannot simulate and a running simulation cannot be
edited. (At least in the current state)
- **net.mograsim.logic.model.am2900**
This plugin contains a model for the
AMD Am2900 Family Microprocessors arranged into a microprogrammable model.
This can be used in the microprogram editor of the Mograsim plugin and in the
Mograsim assembler editor (by using a properly set up instruction set). We
took care that the plugin is independent, meaning that it only provides an
implementation for an extension point of the net.mograsim.machine plugin and
no other Mograsim depends on it.
This is also the way to go if you want
to add your own machine definitions to Mograsim and use them there.
- **net.mograsim.machine**
The machine plugin defines an extension point
that can be extended and implemented in other (your own) plugins to provide
new machines to Mograsim. In addition to the extension point and the most important
interfaces, it contains some commonly required or useful components to build/define
another machine. net.mograsim.logic.model.am2900 for example is such an extension.
The machine plugin itself scans for all available implementations of the interface
given by the extension point, and other parts of the Mograsim plugin get access
to them that way.
- **net.mograsim.plugin.core**
This is - as the name says - the core plugin
of mograsim. Here lie all the Eclipse Platform specific parts that make Mograsim
as an Eclipse plugin work. This includes the different editors, view, settings
and other functional extension to the Eclipse IDE.
- **net.mograsim.plugin.core.nl_de**
This optional plugin provides a German
localization for Mograsim.
- **net.mograsim.plugin.branding**
This contains elements for branding the
feature plugin, and additional resources and raw files (original logo and icon
in SVG and Adobe Illustrator and similar).
- **net.mograsim.plugin.docs**
The Plugin providing the user documentation.
- **net.mograsim.preferences**
A plugin for managing and accessing preferences.
- `features` - _This contains all Mograsim feature plugins_
- **net.mograsim.feature**
The Mograsim feature plugin, containing all the
plugins above and combining them into a feature. A feature is a plugin collection
with additional properties that allows for easy installation by the end user.
For this purpose, it also contains license information, authors, updatesite
location (allows eclipse to automatically check if updates are available) and
more.
- `products` - _This contains standalone Mograsim product(s)_
- **net.mograsim.product**
A product can be pretty much anything (see Eclipse
RCP), in our case, this is simply a pre-configured Eclipse package, comparable
to the packages located at [www.eclipse.org/downloads/packages](https://www.eclipse.org/downloads/packages/).
- `releng` - _Abbreviation for **Rel**ease **Eng**ineering, contains important configuration_
- **net.mograsim.configuration**
This contains the configuration for the
Mograsim project and the build in particular. The central Maven configuration
is located here in a single `pom.xml`, that is the super-parent of all others,
including the generated ones.
- **net.mograsim.updatesite**
This updatesite project collects features
in form of an update site that can be accessed by Eclipse to install new features
or update features. The features are grouped into categories which can come
with further descriptions. The `target/repository/` is the part of the whole
Mograsim project that actually gets deployed. By using Help -> Install New
Software -> Add -> Local, the `repository`-folder can be selected and features
can be installed offline, e.g. to test them.
- **net.mograsim.target**
The target definition for the build. This is a
well-defined environment that we expect the plugins to work in/with. That includes
all plugin dependencies (like all plugins the Eclipse Platform is comprised
of) and the (minimum) JRE that is expected. Some plugins exclusively for testing
are included here, too.
- `tests` - _This contains (integration-like) tests in form of plugin fragments_
- **net.mograsim.logic.core.tests**
- **net.mograsim.logic.model.am2900.tests**
- **net.mograsim.machine.tests**
- `SWTHelper` - _This contains the [SWTHelper](https://github.com/Haspamelodica/SWTHelper)
git submodule._
- `bundles` - _This submodule folder needs to be named like that for Tycho pom-less
build to work._
- **SWTInput** - Contains type specific input fields for SWT.
- **SWTObjectWrappers** - SWT object abstractions to enable zooming and optimizations.
- _SWTSystemInOutApplication_ - _unused_
- _SWTTiledZoomableCanvas_ - _unused_
- **SWTZoomableCanvas** - The SWT canvas we draw the simulation in.
## Build Mograsim
Use the main aggregator `pom.xml` next to this markdown file to build mograsim, take
care to use the correct JDK to run it (see Run Configuration).
A short guide to the [Maven goals (Maven Lifecycle)](https://maven.apache.org/guides/introduction/introduction-to-the-lifecycle.html):
- The `clean` goal will remove all `target`-folders and other generated files like
flattened poms and polyglot build artifacts (all are listed in `.gitignore`).
- The `validate` goal is useful to simply check if the setup itself (Maven Tycho)
is ok and everything needed is available.
- The `integration-test` goal will run the test plugins, the `test` goal beforehand
**will not.**
- I recommend running `clean verify` or `verify`, this will do everything up to and
including the testing.
Please note that Tycho 1.5.0 is not released yet, and thus requires a workaround.
More information can be found under [Maven Core Extension Problems](#mceps).
## Challenges
Not everything is as simple as it seems at first glance.
### Maven Core Extension Problems
The Tycho extra `tycho-pomless` is a Maven core extension allows for simpler structure
and less redundancy. Maven core extensions must be available at [the central maven repository](http://repo.maven.apache.org/maven2/)
(or already in the local repository), you cannot specify an alternative remote repository
in `.mvn/extensions.xml`. If a core extension cannot be resolved, you will get currently
(Maven 3.6.2) only a warning like
> [WARNING] The POM for org.eclipse.tycho.extras:tycho-pomless:jar:1.5.0-SNAPSHOT is missing, no dependency information available
This means that the extension was not found, and it cannot be used, which leads to
a failure later on. To get around that, create a dummy pom that only serves the purpose
to "request" and resolve the extension:
```xml
4.0.0
net.mograsim
net.mograsim.tycho-download
1.0.0
pom
tycho-snapshots
https://repo.eclipse.org/content/repositories/tycho-snapshots/
true
true
always
org.eclipse.tycho.extras
tycho-pomless
1.5.0-SNAPSHOT
```
While that this is not the most compact way, it can be run by the developer and build
server equally easy and does not require special CLI knowledge. As developer, you
need to run that only once (in Eclipse: right click on pom.xml -> Run As -> Maven
clean). For continuous integration, you can insert one more line in the YAML (or
equivalent), like in our case ` - mvn $MAVEN_CLI_OPTS clean`.
### Git Submodules
Git submodules are a challenge with a tycho build, because the projects that reside
in it need to be build, too. But not only that, they need to use the same configuration
for the build, which is problematic if you do not have control over them. The solution
only exists with Tycho 1.5.0 (currently only as snapshot), where deep folder structures
are automatically scanned and poms get gnereated; not every folder requires an aggregator
pom. This however requires (at the moment) certain naming conventions (see section
on Tycho itself).
In our case, [SWTHelper](https://github.com/Haspamelodica/SWTHelper) is a git submodule
containing several plain Java Eclipse projects with OSGi configuration (MANIFEST.MF),
which is the reason this works at all. Due to the naming conventions, the submodule
folder is named `bundles`.
### Maven incompatibility
Maven 3.6.2 is currently incompatible with Tycho <= 1.5.0.
If you encounter
> [FATAL] Non-readable POM "somepath"\tests\.polyglot.pom.tycho: input contained no data @
or
> [FATAL] Non-readable POM "somepath"\bundles\net.mograsim.logic.core\.polyglot..META-INF_MANIFEST.MF: input contained no data @
make sure to use Maven 3.6.1 to fix that (this is the default Eclipse embedded Maven
at the moment).