Java tutorial
/* * Copyright 2011 JBoss Inc * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.jbpm.formbuilder.client.tree; import org.jbpm.formapi.client.CommonGlobals; import org.jbpm.formapi.client.form.FBCompositeItem; import org.jbpm.formapi.client.form.FBFormItem; import org.jbpm.formbuilder.client.bus.ui.FormItemAddedEvent; import org.jbpm.formbuilder.client.bus.ui.FormItemAddedHandler; import org.jbpm.formbuilder.client.bus.ui.FormItemRemovedEvent; import org.jbpm.formbuilder.client.bus.ui.FormItemRemovedHandler; import com.google.gwt.event.shared.EventBus; import com.google.gwt.user.client.ui.Widget; /** * Tree presenter. Handles notifications of form items added and removed * and tells the view to update itself */ public class TreePresenter implements TreeView.Presenter { private final TreeView view; private final EventBus bus = CommonGlobals.getInstance().getEventBus(); public TreePresenter(TreeView treeView) { this.view = treeView; bus.addHandler(FormItemRemovedEvent.TYPE, new FormItemRemovedHandler() { @Override public void onEvent(FormItemRemovedEvent event) { FBFormItem item = event.getFormItem(); view.removeFormItem(item); } }); bus.addHandler(FormItemAddedEvent.TYPE, new FormItemAddedHandler() { @Override public void onEvent(FormItemAddedEvent event) { FBFormItem item = event.getFormItem(); Widget parent = event.getFormItemHolder(); FBCompositeItem parentItem = null; while (parent != null && parentItem == null) { if (parent instanceof FBCompositeItem) { parentItem = (FBCompositeItem) parent; } else { parent = parent.getParent(); } } view.addFormItem(item, parentItem); } }); } }