PI (Programming Interface) Step

The Program Interface Step element is located in the Activity drawer of the process editor palette.

Element Details

This element is one of Xpert.ivy facilities to integrate custom-made software, legacy systems, proprietary applications or any other external system through a Java interface. The Program Interface element will instantiate a Java class that must implement the interface IUserProcessExtension and will call the method perform each time a process comes to the Program Interface. The common way to implement a Program Interface bean is to extend the abstract base class AbstractUserProcessExtension . The interface also includes an inner editor class to parametrize the bean. You will find the documentation of the interface and the abstract class in the Java Doc of the Xpert.ivy Public API.

Note

Since Xpert.ivy 3.x this element has become somewhat obsolete, since it has become very easy to create and call your own Java classes from IvyScript. However, the PI element still provides a standardized interface to a third party Java class and can provide a custom made editor for parametrization.

Inscription

Name Tab

This tab is included in the mask of all process elements and contains the name and a description of the element. See Name Tab for a more detailed description.

Tab PI

On this tab you set the Java class which implements the interface IUserProcessExtension which is called when the PI step is executed. Furthermore, you can define exception handlers to react on errors such as not reachable systems, insufficient privileges and many more.

Figure 5.20. The PI tab

The PI tab

Java Class to Execute

The fully qualified name of the PI Java class implementing IUserProcessExtension . You can use default copy & paste commands, open a Java Type Browser to search for the class or you use the predefined Wait class which just waits for a given period of time. Use the New Bean Class Wizard () to create a new Java source file with an example implementation of the bean class.

Tip

You can add a graphical configuration editor for the Java call (i.e. setting the parameter values) on the PI inscription mask. See section Tab Editor for more details.

Program Exception / Exception Handler

The Exception step which is executed whenever errors during the call to the PI Java class or during the execution of the class are returned.

Timeout

Sets a timeout for the return call to the Java PI class. When the timeout ends without an answer from the PI class, then the Exception step below is executed

Timeout Exception Handler

The Exception step which is executed whenever the timeout ends without an answer from the PI call.

Tab Editor

This tab displays the editor, that can be integrated in the external Java bean of the process element. The editor is implemented as an inner public static class of the Java bean class and must have the name Editor. Additionally the editor class must implement the IProcessExtensionConfigurationEditorEx interface. The common way to implement the editor class is to extend the abstract base class AbstractProcessExtensionConfigurationEditor and to override the methods createEditorPanelContent, loadUiDataFromConfiguration and saveUiDataToConfiguration. The method createEditorPanelContent can be used to build the UI components of the editor. You can add any AWT/Swing component to the given editorPanel parameter. With the given editorEnvironment parameter, which is of the type IProcessExtensionConfigurationEditorEnvironment , you can create text fields that support ivyScript and has smart buttons which provide access to the process data, environment functions and Java classes.

Here is an example of such an editor:

As you can see, the editor provides you access to any process relevant data, which can be used by your own process elements. For instance, you can easily transfer process data to your legacy system.

The following part shows the implementation of the editor shown above. As mentioned above Xpert.ivy provides the IIvyScriptEditor which represents a text field with ivyScript support and smart buttons. Inside createEditorPanelContent use the method createIvyScriptEditor from the editorEnvironment parameter to create an instance of such an editor. Use the loadUiDataFromConfiguration method to read the bean configuration and set them to the UI components. Inside this method you can use the methods getBeanConfiguration or getBeanConfigurationProperty to read the bean configuration. Use the method saveUiDataToConfiguration to save the data in the UI components to the bean configuration. Inside this method you can use the methods setBeanConfiguration or setBeanConfigurationProperty to save the bean configuration.

  public static class Editor extends AbstractProcessExtensionConfigurationEditor
  {
    private IIvyScriptEditor editorUser;
    private IIvyScriptEditor editorEventTyp;
    private IIvyScriptEditor editorLinkId;
    private IIvyScriptEditor editorFieldValue;
    
    @Override
    protected void createEditorPanelContent(Container editorPanel,
            IProcessExtensionConfigurationEditorEnvironment editorEnvironment)
    {
      editorPanel.setLayout(new GridLayout(4,2));
      editorUser = editorEnvironment.createIvyScriptEditor(null,null, "String");
      editorEventTyp = editorEnvironment.createIvyScriptEditor(null,null, "String");
      editorLinkId = editorEnvironment.createIvyScriptEditor(null, null, "String");
      editorFieldValue = editorEnvironment.createIvyScriptEditor(null, null);
      
      editorPanel.add(new JLabel("User"));
      editorPanel.add(editorUser.getComponent());
      editorPanel.add(new JLabel("Event Typ"));
      editorPanel.add(editorEventTyp.getComponent());
      editorPanel.add(new JLabel("Link-Id"));
      editorPanel.add(editorLinkId.getComponent());
      editorPanel.add(new JLabel("Feldwert"));
      editorPanel.add(editorFieldValue.getComponent());        
    }

    @Override
    protected void loadUiDataFromConfiguration()
    {
      editorUser.setText(getBeanConfigurationProperty("User"));
      editorEventTyp.setText(getBeanConfigurationProperty("EventTyp"));
      editorLinkId.setText(getBeanConfigurationProperty("LinkId"));
      editorFieldValue.setText(getBeanConfigurationProperty("Feldwert"));
    }

    @Override
    protected boolean saveUiDataToConfiguration()
    {
      setBeanConfigurationProperty("User", editorUser.getText());
      setBeanConfigurationProperty("EventTyp", editorEventTyp.getText());
      setBeanConfigurationProperty("LinkId", editorLinkId.getText());
      setBeanConfigurationProperty("Feldwert", editorFieldValue.getText());
      return true;
    }
  }    

At runtime you have to evaluate the IvyScript the user have entered into the ivy script editors. If you implement for example the AbstractUserProcessExtension class there is a perform method which is executed at runtime. At this point you want to access the configured data in the editor. The following code snippet show how you can evaluate the value of an IIvyScriptEditor . If you use the IIvyScriptEditor you only get the value by calling the executeIvyScript method of the AbstractUserProcessExtension .

  public CompositeObject perform(IRequestId requestId, CompositeObject in,
     IIvyScriptContext context) throws Exception
  {
    IIvyScriptContext ownContext;
    CompositeObject out;
    out = in.clone();
    ownContext = createOwnContext(context);

    String eventtyp = "";
    String linkId = "";
    String fieldValue = "";
    String user= "";

    user = (String)executeIvyScript(ownContext, getConfigurationProperty("User"));
    eventtyp = (String)executeIvyScript(ownContext, getConfigurationProperty("Event Typ"));
    linkId = (String)executeIvyScript(ownContext, getConfigurationProperty("Link-Id"));
    fieldValue = (String)executeIvyScript(ownContext, getConfigurationProperty("Feldwert"));
    
    // add your call here
    
    return out;
  }           

Complete Code sample

public class MyOwnPiBean extends AbstractUserProcessExtension {
				
				/**
				* @see ch.ivyteam.ivy.process.extension.IUserProcessExtension#perform(ch.ivyteam.ivy.process.engine.IRequestId,
				*      ch.ivyteam.ivy.scripting.objects.CompositeObject,
				*      ch.ivyteam.ivy.scripting.language.IIvyScriptContext)
				*/
				public CompositeObject perform(IRequestId requestId, CompositeObject in,
				IIvyScriptContext context) throws Exception {
				
    				IIvyScriptContext ownContext;
    				CompositeObject out;
    				out = in.clone();
    				ownContext = createOwnContext(context);
				
    				String eventtyp = "";
    				String linkId = "";
    				String fieldValue = "";
    				String user= "";
				
    				StringTokenizer st = new StringTokenizer(getConfiguration(),"|");
    				if(st.hasMoreElements())
        				user= (String)executeIvyScript(context, st.nextElement().toString());
    				if(st.hasMoreElements())
        				eventtyp = (String)executeIvyScript(context, st.nextElement().toString());
    				if(st.hasMoreElements())
        				linkId = (String)executeIvyScript(context, st.nextElement().toString());
    				if(st.hasMoreElements())
        				fieldValue = (String)executeIvyScript(context, st.nextElement().toString());
				
    				//do something with the values				
    				return out;
  				}
				
    				public static class Editor extends JPanel implements IProcessExtensionConfigurationEditorEx {
        				private IProcessExtensionConfigurationEditorEnvironment env;
        				private IIvyScriptEditor editorUser;
        				private IIvyScriptEditor editorEventTyp;
        				private IIvyScriptEditor editorLinkId;
        				private IIvyScriptEditor editorFieldValue;
				
				
        				/**
        				* Constructor for the Editor object
        				*/
        				public Editor() {
            				super(new GridLayout(4,2));
        				}
				
        				/**
        				* Sets the configuration
        				* 
        				* @param config  the configuration as an String	*/
    				public void setConfiguration(String config) {
        				StringTokenizer st = new StringTokenizer(config,"|");
        				if(st.hasMoreElements())
            				editorUser.setText(st.nextElement().toString());
        				if(st.hasMoreElements())
            				editorEventTyp.setText(st.nextElement().toString());
        				if(st.hasMoreElements())
            				editorLinkId.setText(st.nextElement().toString());
        				if(st.hasMoreElements())
            				editorFieldValue.setText(st.nextElement().toString());
    				}
				
    				/**
    				* Gets the component attribute of the Editor object
    				* 
    				* @return this
    				*/
    				public Component getComponent() {
        				return this;
    				}
				
    				/**
    				* Gets the configuration
    				* 
    				* @return The configuration as an String
    				*/
    				public String getConfiguration() {
        				return editorUser.getText() + "|" +  editorEventTyp.getText() +  "|" +
        					editorLinkId.getText() + "|" + editorFieldValue.getText() + "|";
    				}
    				
    				/**
    				* @return boolean
    				*/
    				public boolean acceptInput() {
        				return true;
    				}
				
    				public void setEnvironment(IProcessExtensionConfigurationEditorEnvironment env) {
        				this.env = env;
        				editorUser = env.createIvyScriptEditor(null,null, "String");
        				editorEventTyp = env.createIvyScriptEditor(null,null, "String");
        				editorLinkId = env.createIvyScriptEditor(null, null, "String");
        				editorFieldValue = env.createIvyScriptEditor(null, null);
        				
        				add(new JLabel("User"));
        				add(editorUser.getComponent());
        				add(new JLabel("Event Typ"));
        				add(editorEventTyp.getComponent());
        				add(new JLabel("Link-Id"));
        				add(editorLinkId.getComponent());
        				add(new JLabel("Feldwert"));
        				add(editorFieldValue.getComponent());
        				
   				}
  				}
				}