Goal

• To define new (more logical?) structure of where commands are implemented and defined.
• Allow easier use of commands by the App developers.
• Remove command pooling.
• Get rid of the Commons Chain library (see Greg's comment).

Further (future) goals:

• Better documentation (list of commands with description, and for each command a list of parameters).
• Get rid of the Commons Chain library (see Greg's comment).
• Allow commands to be injected.
• Allow configuration-by-code for commands.

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The Previous Status

The above class diagram represents the current distribution of the command classes into the (basic) packages . As we want to get rid of the Admin Interface module, we need to move the MessageCommand class and the whole tree of the BaseRepositoryCommand class to the another package(s).

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in the releases up to 4.5. 

Implementation

The command classes related to the activation (marked green on the above image) will be were moved to the Activation module (package i.m.module.activation.commands), the rest will be was moved to the Core module, to the i.m.commands.impl package.

The CommandsManager class will be was extended with a method executeCommand(String catalog, String command, Map<String,Object> parameters) , that will allow allows to run commands without need to handle Context etc. The UI classes (actions etc.) should use command by calling this method (i.e. this will be the preferred method, but not the only one).

Command Definitions Reorganisation

The commands are still defined in particular modules, as described in http://documentation.magnolia-cms.com/technical-guide/commands.html - but the catalogs are now additive, i.e. it is possible to define a catalog in one module, and add a new command to the catalog in another module. Anyway, it is still forbidden to have two command of the same name in the catalog - if such situation happens, the CommandsManager will produce RuntimeException on its initialisation.

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Remove Command Pooling

The pooling capabilities will be were removed from the MgnlCommand base class, and the CommandsManager will be  has been changed to create new instance for each getCommand() or executeCommand() call.

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AbstractCommandAction

info.magnolia.ui.modelframework.action.CommandActionBase and AbstractCommandAction and its definition counterpart CommandActionDefinition will allow for easier counterpart info.magnolia.ui.api.action.CommandActionDefinition allows for easy use of commands by the App developers . The Command action class will provide a by handling much of the boilerplate code they would otherwise need to write. 

In most cases it's just a matter of configuration. You define a marker interface extending CommandActionDefinition and bind AbstractCommandAction to it. The CommandActionDefinition needs to define at least the name of the command to execute, optionally it can define a catalog, otherwise it uses the default value, meaning that the command to be executed will be looked up in the registered default catalog of commands. Further parameters can be added in the param subfolder and/or my subclassing CommandActionDefinition as the example below illustrates

Image Added

AbstractCommandAction provides a Map<String, Object> buildParams(final Node node) method which builds a map of parameters which will be passed to the current command for execution. Called It is called by the constructor.

Default implementation returns a map containing the parameters defined at CommandActionDefinition.getParams(). It also adds the following parameters with values retrieved from the passed node.

• Context.ATTRIBUTE_REPOSITORY = current node's workspace name
• Context.ATTRIBUTE_UUID = current node's identifier
• Context.ATTRIBUTE_PATH = current node's path

It will also provide a getCommandsManager() method which will return an instance of CommandsManager to be used for action execution. Typically the execute() method of a subclass action will do something like the following 

getCommandsManager().executeCommand(getDefinition().getCatalog(), getDefinition().getCommand(), getParams());

Proposals for future goals (not to be implemented in this sprint):

Getting rid of the Commons Chain library:

New interface Command (a 'copy' of the one from the Commons Chain library) will be defined in the info.magnolia.commands package. (Option: simply remove 'implements Command' from the MgnlCommand class definition.)

The MgnlCatalog class will be rewritten to provide the functionality of the org.apache.commons.chain.impl.CatalogBase class.

This will also require to remove the dependency to org.apache.commons.chain.Context interface from the interface info.magnolia.context.Context, and cross-check for this dependency throughout the code.

Allow commands to be injected

TODO

Allow configuration-by-code for commands

TODO

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Subclasses can override this method to add further parameters to the command execution. E.g. in the ActivationAction class

 protected Map<String, Object> buildParams(final Node node) {
     Map<String, Object> params = super.buildParams(node);
     params.put(Context.ATTRIBUTE_RECURSIVE, getDefinition().isRecursive());
     return params;
 }