org.azyva.dragom.model.config

Interface PluginDefConfig

public interface PluginDefConfig

Configuration of a NodePlugin within a NodeConfig.

A PluginDefConfig has the classNodePlugin and pluginId properties. These must be provided (pluginId can be null though, null being a possible value). But that does not necessarily mean that the configuration store must explicitly specify them as they can be inferred by the class specified by the pluginClass property.

This is so that it is not necessary in the the Config to specify the plugin interface or plugin ID in the case the specified plugin implementation class supports a default NodePlugin or plugin ID.

If pluginClass refers to a class that implements NodePluginFactory (factory design pattern) NodePluginFactory.getDefaultClassNodePlugin() must be used by implementations to get the value of the classNodePlugin property when not defined. If pluginClass refers to a class that directly implements a sub- interface of NodePlugin (constructor design pattern), it is up to the implementation to implement a default mechanism for the classNodePlugin property. But the following is recommended:

• If the class implements the static method getDefaultClassNodePlugin with no parameter, call this method to get the default value of the property classNodePlugin;
• Otherwise, use the first NodePlugin sub-interface as the default.

Similarly for the pluginId property:

If pluginClass refers to a class that implements NodePluginFactory, NodePluginFactory.getDefaultPluginId must be used implementations to get the value of the pluginId property when not defined. If pluginClass refers to a class that directly implements a sub-interface of NodePlugin, it is up to the implementation to implement a default mechanism for the pluginId property. But the following is recommended:

• If the class implements the static method getDefaultPluginId with the Class of the NodePlugin as parameter (property classNodePlugin), call this method to get the default value of the property pluginId;
• Otherwise, use null as the value of the pluginId property.

The strategy described above for obtaining the default values for the classNodePlugin and pluginId properties is implemented by Util.getDefaultClassNodePlugin and Util.getDefaultPluginId from dragom-core. which implementations can use.

During the design of Config and its members, it was debated whether the responsibility for handling the default values for the classNodePlugin and pluginId properties should be given to Config or more centrally to Node. It was finally decided to give that responsibility to the implementations of this interface, even if it means that the strategy needs to be implemented in multiple places, for the following reasons:

• Simpler implementation of Node;
• From the point of view of the consumers of Config (essentially the Node class) it makes sense to not have to worry about these default details and see a clean configuration;
• The duplication of code is not a big problem as most of the strategy is implemented by Util.getDefaultClassNodePlugin and Util.getDefaultPluginId.

Author:

David Raymond

See Also:

Config

Method Summary

Modifier and Type	Method and Description
Class<? extends NodePlugin>	getClassNodePlugin()
String	getPluginClass() Returns the plugin implementation class name.
String	getPluginId()
boolean	isOnlyThisNode()

Method Detail

getClassNodePlugin

Class<? extends NodePlugin> getClassNodePlugin()

Returns:

Class of the NodePlugin.

getPluginId

String getPluginId()

Returns:

Plugin ID. Can be null.

getPluginClass

String getPluginClass()

Returns the plugin implementation class name.

null to avoid inheritance.

This class must either implement NodePluginFactory or have a constructor and implement the NodePlugin and the appropriate sub-interface identified by getClassNodePlugin().

Returns:

See description.

isOnlyThisNode

boolean isOnlyThisNode()

Returns:

Indicates that this PluginDefConfig applies specifically to the NodeConfig on which it is defined, as opposed to being inherited by child NodeConfig when interpreted by the Model.