Class diagram generation cannot handle windows template paths

[schmalzing]

Issue description

Class diagram generation fails on Windows when an absolute Windows path is passed as the FreeMarker template name. The path contains backslashes (), whereas FreeMarker template names must use forward slashes (/) and are interpreted relative to the configured TemplateLoader.

Steps to reproduce:

Run CD2PojoTool with an absolute template path such as:

C:\Users\AUser\Documents\montiarc\generators\ma2jsim\main\cd2pojo\CD2Java.ftl

This causes the following error:

0xA0560 Unable to load template: Template not found ...
Warning: The name contains backslash ("\") instead of slash ("/")

Expected behavior:

The generator should support fully qualified template paths on Windows and load the specified template normally. Windows path separators (\) should be handled correctly, for example by normalizing the path before resolving the template.

Actual behavior:

The absolute Windows path is treated as a FreeMarker template name. Consequently, the already configured MontiCoreFileTemplateLoader for ...\cd2pojo cannot resolve the template.

[luepges]

We are limited by FreeMarker: https://freemarker.apache.org/docs/api/freemarker/template/Configuration.html#getTemplate(java.lang.String,java.util.Locale,java.lang.Object,java.lang.String,boolean,boolean)

The exact syntax of the name depends on the underlying TemplateLoader, but the cache makes some assumptions. First, the name is expected to be a hierarchical path, with path components separated by a slash character (not with backslash!). The path (the name) given here must not begin with slash; it's always interpreted relative to the "template root directory". Then, the .. and . path meta-elements will be resolved. For example, if the name is a/../b/./c.ftl, then it will be simplified to b/c.ftl. The rules regarding this are the same as with conventional UN*X paths. The path must not reach outside the template root directory, that is, it can't be something like "../templates/my.ftl" (not even if this path happens to be equivalent with "/my.ftl").

[schmalzing]

Thats not a limitation, we just need to handle the path beforehand.

1. Ensure that the given path to the config is part of the template root directory (coco)
2. Normalize the path
   a) Calculate the relative path from the template root
   b) Replace slashes if windows path