## How to show the parameters of a extension in the property editor
VSM supports to list all the parameters(properties) of a plugin in the property editor, which makes it convenient for users to set the values of required parameters. <br/>
In this tutorial we will use the plugin "ReetiExecutor" as an example to introduce how to achieve this function.<br/><br/>
The interface ExportableProperties contains the methods to provide the properties of the decive and the properties of the agent, which needs to be implemented by our plugin.<br/>
```
public interface ExportableProperties {
// return properties of the decive
Map<ProjectProperty, ProjectValueProperty> getExportableProperties();
// return properties of the agent
Map<ProjectProperty, ProjectValueProperty> getExportableAgentProperties();
}
```
ProjectProperty is used to store the name of a property.
```
public class ProjectProperty {
// description of the current property
private final String description;
// name of the current property
String name;
// specify whether the property is necessary or not
boolean required;
public ProjectProperty(String name, boolean required){
this.name = name;
this.required = required;
this.description = "";
}
public ProjectProperty(String name ){
this.name = name;
this.required = false;
this.description = "";
}
public ProjectProperty(String name, String description){
this.name = name;
this.description = description;
this.required = false;
}
public ProjectProperty(String name, boolean required, String description){
this.name = name;
this.description = description;
this.required = required;
}
...
}
```
ProjectValueProperty is used to store the default value of a property.
```
public class ProjectValueProperty implements PropertyValue {
...
// used by SelectableRenderer
private final ArrayList<String> options;
// type of the value: STRING, LIST, BOOLEAN, NUMERIC, FILEPATH
ValueTYPE type;
// the defalut value
Object defaultValue;
// specify different input forms
ValueRenderable renderer;
...
public ProjectValueProperty(ValueTYPE type, Object defaultValue,
ValueRenderable renderer){
this.type = type;
this.defaultValue = defaultValue;
this.renderer = renderer;
this.required = false;
this.options = new ArrayList<>();
this.renderer.setValueProperty(this);
}
public ProjectValueProperty(ValueTYPE type, Object defaultValue,
ValueRenderable renderer, boolean required){
this.type = type;
this.defaultValue = defaultValue;
this.renderer = renderer;
this.required = required;
this.options = new ArrayList<>();
this.renderer.setValueProperty(this);
}
public ProjectValueProperty(ValueTYPE type, Object defaultValue,
ValueRenderable renderer, boolean required,
ArrayList<String> options){
this.type = type;
this.defaultValue = defaultValue;
this.renderer = renderer;
this.required = required;
this.renderer.setValueProperty(this);
this.options = options;
}
...
}
```
In this example, we implement ExportableProperties and override the methods getExportableProperties() and getExportableAgentProperties() using ReetiExecutor.java.
```
public class ReetiExecutor extends ActivityExecutor implements ExportableProperties {
...
private ReetiProjectProperty reetiProjectProperty = new ReetiProjectProperty();
...
@Override
public Map<ProjectProperty, ProjectValueProperty> getExportableProperties() {
return reetiProjectProperty.getExportableProperties();
}
@Override
public Map<ProjectProperty, ProjectValueProperty> getExportableAgentProperties() {
return reetiProjectProperty.getExportableAgentProperties();
}
}
```
The class ReetiProjectProperty.java is used to input the values of ProjectProperty and ProjectValueProperty in the map. We add "lhost" for the device into the following code.
```
public class ReetiProjectProperty implements ExportableProperties {
HashMap<ProjectProperty, ProjectValueProperty> exportableProperties = new HashMap<>();
public ReetiProjectProperty(){
ProjectProperty lhost = new ProjectProperty("lhost", true,
"The address of the computer running VSM ");
ProjectValueProperty lhostVP = new ProjectValueProperty(ValueTYPE.STRING,
"127.0.0.1",
new StringRender());
exportableProperties.put(lhost, lhostVP);
}
@Override
public Map<ProjectProperty, ProjectValueProperty> getExportableProperties() {
return exportableProperties;
}
@Override
public Map<ProjectProperty, ProjectValueProperty> getExportableAgentProperties() {
return null;
}
}
```
After that, we can find "lhost" in the list of the combobox.
<img src="../../images/tutorials/lhostInCombobox.png" width="600" height="660"/>
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