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.wicket.protocol.ws.api; import java.io.IOException; import java.util.Collection; import java.util.Collections; import org.apache.wicket.Component; import org.apache.wicket.MarkupContainer; import org.apache.wicket.Page; import org.apache.wicket.core.request.handler.logger.PageLogData; import org.apache.wicket.markup.head.IHeaderResponse; import org.apache.wicket.page.PartialPageUpdate; import org.apache.wicket.page.XmlPartialPageUpdate; import org.apache.wicket.request.ILogData; import org.apache.wicket.request.IRequestCycle; import org.apache.wicket.request.component.IRequestablePage; import org.apache.wicket.request.mapper.parameter.PageParameters; import org.apache.wicket.util.lang.Args; import org.apache.wicket.util.visit.IVisit; import org.apache.wicket.util.visit.IVisitor; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * A handler of WebSocket requests. * * @since 6.0 */ public class WebSocketRequestHandler implements IWebSocketRequestHandler { private static final Logger LOG = LoggerFactory.getLogger(WebSocketRequestHandler.class); private final Page page; private final IWebSocketConnection connection; private PartialPageUpdate update; private PageLogData logData; public WebSocketRequestHandler(final Component component, final IWebSocketConnection connection) { this.page = Args.notNull(component, "component").getPage(); this.connection = Args.notNull(connection, "connection"); } @Override public void push(CharSequence message) { if (connection.isOpen()) { Args.notNull(message, "message"); try { connection.sendMessage(message.toString()); } catch (IOException iox) { LOG.error("An error occurred while pushing text message.", iox); } } else { LOG.warn("The websocket connection is already closed. Cannot push the text message '{}'", message); } } @Override public void push(byte[] message, int offset, int length) { if (connection.isOpen()) { Args.notNull(message, "message"); try { connection.sendMessage(message, offset, length); } catch (IOException iox) { LOG.error("An error occurred while pushing binary message.", iox); } } else { LOG.warn("The websocket connection is already closed. Cannot push the binary message '{}'", message); } } @Override public void add(Component component, String markupId) { getUpdate().add(component, markupId); } private PartialPageUpdate getUpdate() { if (update == null) { update = new XmlPartialPageUpdate(page); } return update; } @Override public void add(Component... components) { for (final Component component : components) { Args.notNull(component, "component"); if (component.getOutputMarkupId() == false) { throw new IllegalArgumentException( "cannot update component that does not have setOutputMarkupId property set to true. Component: " + component.toString()); } add(component, component.getMarkupId()); } } @Override public final void addChildren(MarkupContainer parent, Class<?> childCriteria) { Args.notNull(parent, "parent"); Args.notNull(childCriteria, "childCriteria"); parent.visitChildren(childCriteria, new IVisitor<Component, Void>() { @Override public void component(final Component component, final IVisit<Void> visit) { add(component); visit.dontGoDeeper(); } }); } @Override public void appendJavaScript(CharSequence javascript) { getUpdate().appendJavaScript(javascript); } @Override public void prependJavaScript(CharSequence javascript) { getUpdate().prependJavaScript(javascript); } @Override public Collection<? extends Component> getComponents() { if (update == null) { return Collections.emptyList(); } else { return update.getComponents(); } } @Override public final void focusComponent(Component component) { if (component != null && component.getOutputMarkupId() == false) { throw new IllegalArgumentException( "cannot update component that does not have setOutputMarkupId property set to true. Component: " + component.toString()); } final String id = component != null ? ("'" + component.getMarkupId() + "'") : "null"; appendJavaScript("Wicket.Focus.setFocusOnId(" + id + ");"); } @Override public IHeaderResponse getHeaderResponse() { return getUpdate().getHeaderResponse(); } @Override public Page getPage() { return page; } @Override public Integer getPageId() { return page.getPageId(); } @Override public boolean isPageInstanceCreated() { return true; } @Override public Integer getRenderCount() { return page.getRenderCount(); } @Override public ILogData getLogData() { return logData; } @Override public Class<? extends IRequestablePage> getPageClass() { return page.getPageClass(); } @Override public PageParameters getPageParameters() { return page.getPageParameters(); } @Override public void respond(IRequestCycle requestCycle) { if (update != null) { update.writeTo(requestCycle.getResponse(), "UTF-8"); } } @Override public void detach(IRequestCycle requestCycle) { if (logData == null) { logData = new PageLogData(page); } if (update != null) { update.detach(requestCycle); update = null; } } }