Run Configurations

It was mentioned above that persistent properties could be either Cloneable or String or any primitive type. But if one uses the Settings language inside run configurations, those properties should also support xml persistence. Strings and primitives are persisted as usual. For objects the persistence is more complicated. Two types of properties are persisted for an object: public instance fields and properties with setXXX and getXXX methods. So, if one wish to use some complex type for a persistent property, he should either make all important fields public or provide setXXX and getXXX methods for whatever he wants to persist.

One of the two basic features of the Settings language is easy integration of one configuration into another. For that template persistent properties are used.

The second basic feature of the Settings language is template parameters. These somewhat resemble constructor parameters in java. For example, if one creates a configuration for choosing a node, he may want to parametrize the configuration with nodes concept. The concept is not a persistent parameter in this case: it is not chosen by the user. This is a parameter specified at configuration creation.

Each command can have several execute sections. Each of this sections defines several execution parameters. There are parameters of two types: required and optional. Optional parameters can have default values and could be ommited when the command is started, while required cannot have default values and they are mandatory. Any two execute sections of the command should have different (by types) lists of required parameters. One execute section can invoke another execute section. Each execute section should return either values of process or ProcessHandler types.

To start a process from a command execute section ProcessBuilderExpression is used. It is a simple list of command parts. Each part is either ProcessBuilderPart, which consists of an expression of type string or list<string>, or a ProcessBuilderKeyPart, which represents a parameter with a key (like "-classpath /path/to/classes"). When the code generated from ProcessBuilderExpression is invoked, each part is tested for being null or empty and ommited if so. Then, each part is split into multiple parts by spaces. So if you intent to provide a command part with a space in it and do not wish it to be split (for example, you have a file path with spaces), you have to put it into double quotes ("). The working directory of created process could be specified in the Inspector.

To integrate a command with the debugger, two things are required to be specified:

• the specific debugger to integrate with;

• the command line arguments for a process.

To specify a debugger you can use DebuggerReference – an expression of debugger type in jetbrains.mps.debug.apiLang – to reference a specific debugger. Debugger settings must be an object of type IDebuggerSettings.

Executor is a node, which describes how a process is started for this run configuration. It takes the settings that the user entered and creates a process from it. So, the executor's execute methods should return an instance of type process. This is done via StartProcessHandlerStatement. Anything that has a type process or ProcessHandler could be passed to it. A process could be created in three different ways:

1. via command;

2. via ProcessBuilderExpression (recommended to use in commands only);

3. by creating new instance of the ProcessHandler class; this method is recommended only if the above two do not fit you, for example when you are creating a run configuration for remote debugging and you do not really need to start a process.

The executor itself consists of the following sections:

1. "for" section where the configuration this executor is for and an alias for it is specified;

2. "can" section where the ability of run/debug this configuration is specified; if the command is not used in this executor, one must provide an instance of DebuggerConfiguration here;

3. "before" section with the call of tasks, which could be executed before this configuration run, such as Make;

4. "execute" section where the process itself is created.

If a command is used to start a process, nothing should be done apart from specifying a configuration as debuggable (by selecting "debug" in the executor). However, if a custom debugger integration is required, it is done the same way as in the command declaration.

Producers for a run configuration describe how to create this configuration for various nodes or groups of nodes, models, modules or a project. This makes run configurations easily discoverable for users since for each producer they will see an action in the context menu suggesting to run the selected item. Also this simplifies configuring because it gives a default way to execute something without seeing the editing dialog first.

Each producer specifies one run configuration that it creates. It can have several produce from sections for each kind of source the configuration can be produced from. This source should be one of the following: node<>, nlist<>, model, module, project. Apart from source, each produce from section has a create section – a concept function parametrized with a source. The function should return either the created run configuration or null if it cannot be created for some reason.

In this example an editor for a "Person" is created. This editor edits two properties of a person: name and e-mail address.

PersonEditor could be used from java code in the following way:

public class SettingsEditorDialogTest {
  public static void main(string[] args) {
    SwingUtilities.invokeLater(new Runnable() {
      public void run() {
        // create PersonEditor
        template configuration<PersonEditor> personEditor = new PersonEditor();
        // create dialog
        SettingsEditorDialog dialog = new SettingsEditorDialog(personEditor);
        // show dialog
        dialog.setVisible(true);
        // print name and email, specified by user
        System.out.println("name = " + personEditor.myName);
        System.out.println("email = " + personEditor.myEmail);
      }
    });
  }
}

This is an example of a simple command, which starts a given executable with programParameters in a given workingDirectory.

This is an example of a BeforeTask which performs compilation of a source file with the gcc command. It also demonstrates how to use commands outside of run configurations executors.

Note that this is just a toy example, in a real-life scenarios the task should show a progress window while compiling, for example.

This is an actual executor for the Java run configuration from MPS.

This is a producer for Java run configuration from MPS.

You can see here three "produce from" sections. A Java run configuration is created here from nodes of ClassConcept, StaticMethodDeclaration or IMainClass.

Lets suppose you have a node of a concept which is generated into a java class with a main method and you wish to run this node from MPS. Then you do not have to create a run confgiuration in this case, but you should do the following:

1. The concept you wish to run should implement IMainClass concept from jetbrains.mps.execution.util language. To specify when the node can be executed, override isNodeRunnable method.

2. Unit information should be generated for the concept. Unit information is required to correctly determine the class name which is to be executed. You can read more about unit information, as whell as about all trace information, in Debugger section of MPS documentation. To ensure this check that one of the following conditions are satisfied:

   1. a ClassConcept from jetbrains.mps.baseLanguage is generated from the node;

   2. a node is generated into text (the language uses textGen aspect for generation) and the concept of the node implements UnitConcept interface from jetbrains.mps.traceable;

   3. a node is genearted into a concept for which one of the three specified conditions is satisfied.