Your first Zest Project

3.1. Getting started

Create a new Eclipse RCP application "sawan.modi.zest.first". Use the "Eclipse RCP with a view" as a template. Add "org.eclipse.zest.core" and "org.eclipse.zest.layouts" as dependencies to your MANIFEST.MF.

Change the coding of "View.java" to the following. This coding creates a simple graph and connects its elements.

    
package sawan.modi.zest.first;

import org.eclipse.swt.SWT;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.ui.part.ViewPart;
import org.eclipse.zest.core.widgets.Graph;
import org.eclipse.zest.core.widgets.GraphConnection;
import org.eclipse.zest.core.widgets.GraphNode;
import org.eclipse.zest.core.widgets.ZestStyles;
import org.eclipse.zest.layouts.LayoutStyles;
import org.eclipse.zest.layouts.algorithms.SpringLayoutAlgorithm;
import org.eclipse.zest.layouts.algorithms.TreeLayoutAlgorithm;

public class View extends ViewPart {
 public static final String ID = "sawan.modi.zest.first.view";
 private Graph graph;
 private int layout = 1;

 public void createPartControl(Composite parent) {
  // Graph will hold all other objects
  graph = new Graph(parent, SWT.NONE);
  // Now a few nodes
  GraphNode node1 = new GraphNode(graph, SWT.NONE, "Jim");
  GraphNode node2 = new GraphNode(graph, SWT.NONE, "Jack");
  GraphNode node3 = new GraphNode(graph, SWT.NONE, "Joe");
  GraphNode node4 = new GraphNode(graph, SWT.NONE, "Bill");
  // Lets have a directed connection
  new GraphConnection(graph, ZestStyles.CONNECTIONS_DIRECTED, node1,
    node2);
  // Lets have a dotted graph connection
  new GraphConnection(graph, ZestStyles.CONNECTIONS_DOT, node2, node3);
  // Standard connection
  new GraphConnection(graph, SWT.NONE, node3, node1);
  // Change line color and line width
  GraphConnection graphConnection = new GraphConnection(graph, SWT.NONE,
    node1, node4);
  graphConnection.changeLineColor(parent.getDisplay().getSystemColor(
    SWT.COLOR_GREEN));
  // Also set a text
  graphConnection.setText("This is a text");
  graphConnection.setHighlightColor(parent.getDisplay().getSystemColor(
    SWT.COLOR_RED));
  graphConnection.setLineWidth(3);
  graphConnection.addListener(SWT.SELECTED, new Listener() {

   @Override
   public void handleEvent(Event event) {
    System.out.println("Selected");
   }

  });
  graph.setLayoutAlgorithm(new SpringLayoutAlgorithm(
    LayoutStyles.NO_LAYOUT_NODE_RESIZING), true);

 }

 public void setLayoutManager() {
  switch (layout) {
  case 1:
   graph.setLayoutAlgorithm(new TreeLayoutAlgorithm(
     LayoutStyles.NO_LAYOUT_NODE_RESIZING), true);
   layout++;
   break;
  case 2:
   graph.setLayoutAlgorithm(new SpringLayoutAlgorithm(
     LayoutStyles.NO_LAYOUT_NODE_RESIZING), true);
   layout = 1;
   break;

  }

 }

 /**
  * Passing the focus request to the viewer's control.
  */
 public void setFocus() {
 }
}
   

Run you application and you should see the graph.

3.2. Select layout manager via a command

Create a command with the following default handler "sawan.modi.zest.first.handler.ChangeLayout" which will change the layout for the graph. Assign the command to the menu.

    
package sawan.modi.zest.first.handler;

import org.eclipse.core.commands.AbstractHandler;
import org.eclipse.core.commands.ExecutionEvent;
import org.eclipse.core.commands.ExecutionException;
import org.eclipse.ui.IViewPart;
import org.eclipse.ui.handlers.HandlerUtil;

import sawan.modi.zest.first.View;

public class ChangeLayout extends AbstractHandler {

 @Override
 public Object execute(ExecutionEvent event) throws ExecutionException {
  IViewPart findView = HandlerUtil.getActiveWorkbenchWindow(event)
    .getActivePage().findView("sawan.modi.zest.first.view");
  View view = (View) findView;
  view.setLayoutManager();
  return null;
 }

}

   

Run your application, if you select your command the layout of your view should change.