org.eclipse.core.runtime

Interface IExecutableExtension

public interface IExecutableExtension

Interface for executable extension classes that require access to their configuration element, or implement an extension adapter.

Extension adapters are typically required in cases where the extension implementation does not follow the interface rules specified by the provider of the extension point. In these cases, the role of the adapter is to map between the extension point interface, and the actual extension implementation. In general, adapters are used when attempting to plug-in existing Java implementations, or non-Java implementations (e.g., external executables).

This interface can be used without OSGi running.

Clients may implement this interface.

See Also:

IConfigurationElement.createExecutableExtension(String)

Method Summary

Modifier and Type	Method and Description
void	setInitializationData(IConfigurationElement config, java.lang.String propertyName, java.lang.Object data) This method is called by the implementation of the method IConfigurationElement.createExecutableExtension on a newly constructed extension, passing it its relevant configuration information.

Method Detail

setInitializationData

void setInitializationData(IConfigurationElement config,
                           java.lang.String propertyName,
                           java.lang.Object data)
                    throws CoreException

This method is called by the implementation of the method IConfigurationElement.createExecutableExtension on a newly constructed extension, passing it its relevant configuration information. Most executable extensions only make use of the first two call arguments.

Regular executable extensions specify their Java implementation class name as an attribute of the configuration element for the extension. For example

     <action run="com.example.BaseAction"/>
 

In the above example, this method would be called with a reference to the <action> element (first argument), and "run" as the name of the attribute that defined this executable extension (second argument).

The last parameter is for the specific use of extension adapters and is typically not used by regular executable extensions.

There are two supported ways of associating additional adapter-specific data with the configuration in a way that is transparent to the extension point implementor:

(1) by specifying adapter data as part of the implementation class attribute value. The Java class name can be followed by a ":" separator, followed by any adapter data in string form. For example, if the extension point specifies an attribute "run" to contain the name of the extension implementation, an adapter can be configured as

     <action run="com.example.ExternalAdapter:./cmds/util.exe -opt 3"/>
 

(2) by converting the attribute used to specify the executable extension to a child element of the original configuration element, and specifying the adapter data in the form of xml markup. Using this form, the example above would become

     <action>
         <run class="com.xyz.ExternalAdapter">
             <parameter name="exec" value="./cmds/util.exe"/>
             <parameter name="opt"  value="3"/>
         </run>
     </action>
 

Form (2) will typically only be used for extension points that anticipate the majority of extensions configured into it will in fact be in the form of adapters.

In either case, the specified adapter class is instantiated using its 0-argument public constructor. The adapter data is passed as the last argument of this method. The data argument is defined as Object. It can have the following values:

• null, if no adapter data was supplied
• in case (1), the initialization data string is passed as a String
• in case (2), the initialization data is passed as a Hashtable containing the actual parameter names and values (both Strings)

Parameters:

config - the configuration element used to trigger this execution. It can be queried by the executable extension for specific configuration properties

propertyName - the name of an attribute of the configuration element used on the createExecutableExtension(String) call. This argument can be used in the cases where a single configuration element is used to define multiple executable extensions.

data - adapter data in the form of a String, a Hashtable, or null.

Throws:

CoreException - if error(s) detected during initialization processing

See Also:

IConfigurationElement.createExecutableExtension(String)