final TextBox arrayElementCount = new TextBox();
arrayElementCount.setText("1");
panel.add(arrayElementCount);
final Button createInstance = new Button("Create instance");
createInstance.addMouseEventListener(new MouseEventAdapter() {
public void onClick(final MouseClickEvent event) {
final int elementCount = Integer.parseInt(arrayElementCount.getText());
SerializationBenchmarker.this.setObject(createTree(elementCount));
SerializationBenchmarker.this.log("", "Created instance that will be serialized, with " + elementCount + " elements.");
}