Java tutorial
/** * Copyright (c) 2015 Bosch Software Innovations GmbH and others. * * All rights reserved. This program and the accompanying materials * are made available under the terms of the Eclipse Public License v1.0 * which accompanies this distribution, and is available at * http://www.eclipse.org/legal/epl-v10.html */ package org.eclipse.hawkbit.ui.tenantconfiguration; import java.util.ArrayList; import java.util.List; import com.vaadin.ui.CustomComponent; /** * Base class for all configuration views. This class implements the logic for * the handling of the configurations in a consistent way. * */ public abstract class BaseConfigurationView extends CustomComponent implements ConfigurationGroup { private static final long serialVersionUID = 1L; private final List<ConfigurationItemChangeListener> configurationChangeListeners = new ArrayList<>(); protected void notifyConfigurationChanged() { configurationChangeListeners.forEach(ConfigurationItemChangeListener::configurationHasChanged); } @Override public void addChangeListener(final ConfigurationItemChangeListener listener) { configurationChangeListeners.add(listener); } @Override public boolean isUserInputValid() { // default return value is true, because often user can only choose from // different valid options. return true; } }