Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you 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.apache.tamaya.ui.events; import com.vaadin.data.Item; import com.vaadin.data.Property; import com.vaadin.navigator.View; import com.vaadin.navigator.ViewChangeListener; import com.vaadin.shared.ui.label.ContentMode; import com.vaadin.ui.Button; import com.vaadin.ui.CheckBox; import com.vaadin.ui.HorizontalLayout; import com.vaadin.ui.Label; import com.vaadin.ui.Notification; import com.vaadin.ui.Table; import com.vaadin.ui.TextField; import org.apache.tamaya.events.ConfigEvent; import org.apache.tamaya.events.ConfigEventListener; import org.apache.tamaya.events.ConfigEventManager; import org.apache.tamaya.spi.ServiceContextManager; import org.apache.tamaya.ui.UIConstants; import org.apache.tamaya.ui.ViewProvider; import org.apache.tamaya.ui.components.VerticalSpacedLayout; import org.apache.tamaya.ui.services.MessageProvider; import javax.annotation.Priority; import java.util.Date; /** * Tamaya View for observing the current event stream. */ public class EventView extends VerticalSpacedLayout implements View { /** * Provider used to register the view. */ @Priority(20) public static final class Provider implements ViewProvider { @Override public ViewLifecycle getLifecycle() { return ViewLifecycle.EAGER; } @Override public String getName() { return "view.events.name"; } @Override public String getUrlPattern() { return "/events"; } @Override public String getDisplayName() { return getName(); } @Override public View createView(Object... params) { return new EventView(); } } private CheckBox changeMonitorEnabled = new CheckBox(ServiceContextManager.getServiceContext() .getService(MessageProvider.class).getMessage("view.events.button.enableMonitoring")); private Button clearViewButton = new Button(ServiceContextManager.getServiceContext() .getService(MessageProvider.class).getMessage("view.events.button.clearView")); private TextField pollingInterval = new TextField(ServiceContextManager.getServiceContext() .getService(MessageProvider.class).getMessage("view.events.field.pollingInterval")); private Table eventsTable = new Table(ServiceContextManager.getServiceContext() .getService(MessageProvider.class).getMessage("view.events.table.name")); public EventView() { Label caption = new Label(ServiceContextManager.getServiceContext().getService(MessageProvider.class) .getMessage("view.events.name")); Label description = new Label(ServiceContextManager.getServiceContext().getService(MessageProvider.class) .getMessage("view.events.description"), ContentMode.HTML); ConfigEventManager.addListener(new ConfigEventListener() { @Override public void onConfigEvent(ConfigEvent<?> event) { addEvent(event); } }); changeMonitorEnabled.addValueChangeListener(new Property.ValueChangeListener() { @Override public void valueChange(Property.ValueChangeEvent valueChangeEvent) { ConfigEventManager.enableChangeMonitoring(changeMonitorEnabled.getValue()); if (changeMonitorEnabled.getValue()) { Notification.show("Event Monitoring (Polling) active."); } else { Notification.show("Event Monitoring (Polling) inactive."); } } }); clearViewButton.addClickListener(new Button.ClickListener() { @Override public void buttonClick(Button.ClickEvent clickEvent) { eventsTable.removeAllItems(); Notification.show("Events cleared."); } }); HorizontalLayout eventSettings = new HorizontalLayout(); eventSettings.addComponents(changeMonitorEnabled, new Label(" Polling Interval"), pollingInterval, clearViewButton); changeMonitorEnabled.setValue(ConfigEventManager.isChangeMonitoring()); pollingInterval.setValue(String.valueOf(ConfigEventManager.getChangeMonitoringPeriod())); pollingInterval.setRequired(true); pollingInterval.addValueChangeListener(new Property.ValueChangeListener() { @Override public void valueChange(Property.ValueChangeEvent valueChangeEvent) { try { long millis = Long.parseLong((String) valueChangeEvent.getProperty().getValue()); ConfigEventManager.setChangeMonitoringPeriod(millis); Notification.show("Updated Event Monitoring Poll Interval to " + millis + " milliseconds."); } catch (Exception e) { Notification.show("Cannot update Event Monitoring Poll Interval to " + valueChangeEvent.getProperty().getValue(), Notification.Type.ERROR_MESSAGE); } } }); eventsTable.addContainerProperty("Timestamp", Date.class, null); eventsTable.addContainerProperty("Type", String.class, "?"); eventsTable.addContainerProperty("Payload", String.class, "<empty>"); eventsTable.addContainerProperty("Version", String.class, "?"); eventsTable.setPageLength(20); eventsTable.setWidth("100%"); eventsTable.setResponsive(true); caption.addStyleName(UIConstants.LABEL_HUGE); description.addStyleName(UIConstants.LABEL_LARGE); addComponents(caption, description, eventSettings, eventsTable); } private void addEvent(ConfigEvent<?> evt) { Object newItemId = eventsTable.addItem(); Item row = eventsTable.getItem(newItemId); row.getItemProperty("Timestamp").setValue(new Date(evt.getTimestamp())); row.getItemProperty("Type").setValue(evt.getResourceType().getSimpleName()); String value = String.valueOf(evt.getResource()); String valueShort = value.length() < 150 ? value : value.substring(0, 147) + "..."; row.getItemProperty("Payload").setValue(valueShort); row.getItemProperty("Version").setValue(evt.getVersion()); } private String getCaption(String key, String value) { int index = key.lastIndexOf('.'); if (index < 0) { return key + " = " + value; } else { return key.substring(index + 1) + " = " + value; } } @Override public void enter(ViewChangeListener.ViewChangeEvent event) { } }