Rework naming setting/defaults in Java code generator

[tkutz]

The Java code generator defines certain defaults and naming logic that does not always work as expected. We should simplify it, and maybe even clean up the generator model in the regards.

For a simple statechart there are three files generated:

1. IStatemachine.java (Lib)
2. ISimpleStatemachine.java (API)
3. SimpleStatemachine.java (Impl)

Current behavior: package naming

Default

• package name is [projectName] for Lib, and [projectName].[statechartName] for API and Impl
  • if project name contains invalid characters, e.g "-", there are compilation errors

Using Naming.basePackage

• package name is [basePackage] for Lib, and [basePackage].[statechartName] for API and Impl

Using Naming.implementationSuffix

• package name is [basePackage] for Lib, and [basePackage].[statechartName][implementationSuffix] for API and Impl
  • Please note that there is no dot between statechart name and the suffix in the package name which looks weird for me
• the class name does not change

Using statechart namespace

• does not have any effect on package name

Current behavior: file naming

• General Interface: IStatemachine.java
• Statechart specific interface: I[statechart.name.toFirstUpper]Statemachine.java
• Statechart implementation: [statechart.name.toFirstUpper]Statemachine.java

Proposal: package naming (as discussed with ATE)

Default

• use the default (unnamed) package for API and Impl
  • This would avoid the problems we have when invalid characters are used in the project name
• use yakindu namespace for Lib files, e.g. com.yakindu.scr (SCR for Statechart Runtime)

** Use explicit package naming features:

• libraryPackage: package name for Lib files
• apiPackage: package name for API files (analog to apiTargetFolder)
• basePackage: package name for Impl files, and API files if no apiPackage defined

Using statechart namespace will add the namespace to the package name

• package name is [packageName].[namespace] for API and Impl, but stays default for Lib

Using Naming.implementationSuffix

• Remove this parameter and add typeName instead (see below)

Proposal: file naming

• General Interface: IStatemachine.java
• Statechart specific interface: I[statechart.name or typeName].java
• Statechart implementation: [statechart.name or typeName].java => no implicit suffix, no implicit toFirstUpper

Also relevant when changing this, is to change the default statechart name in the new statechart wizard to Statechart.sct, as the current name default.sct is already a Java keyword and would generate invalid code now.

Together with these changes we can add the following generator model validation rules:

• The statechart has no namespace, and no basePackage is defined => warning, generation into unnamed default package is discouraged in Java. With a hint how to change this.
• The statechart name is lower cased and no typeName defined => warning, generation of lower cased types is discouraged in Java. With a hint how to change this.

[tkutz]

See also https://github.com/Yakindu/statecharts/issues/2635 https://github.com/Yakindu/statecharts/issues/1000

[tkutz]

@terfloth let's define the desired behavior