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.markup.html.link; import org.apache.wicket.markup.ComponentTag; import org.apache.wicket.model.IModel; import org.apache.wicket.model.Model; import org.apache.wicket.protocol.http.WebApplication; import org.apache.wicket.request.UrlUtils; import org.apache.wicket.request.cycle.RequestCycle; import org.apache.wicket.request.flow.RedirectToUrlException; /** * <p> * A simple anchor link (<a href="http://url">) pointing to any URL. Usually this is used for * links to destinations outside of Wicket. * </p> * * <p> * <strong>Note</strong>: in the case when the support for cookies in the browser is disabled the * user's jsessionid will leak in the 'Referrer' header after clicking this link. If this is a * problem for the application then better use a {@link Link} which redirects to a shared resource * (see * {@link WebApplication#mountResource(String, org.apache.wicket.request.resource.ResourceReference)} * , e.g. "/myapp/redirecting-resource?url=...") which on its side redirects to the new URL using * {@link RedirectToUrlException}. Another option is to use <code>rel="noreferrer"</code> attribute * in your markup but this will work only in the modern browsers (supporting HTML5 standard). * * @author Juergen Donnerstag */ public class ExternalLink extends AbstractLink { private static final long serialVersionUID = 1L; private boolean contextRelative = false; /** * The popup specification. If not-null, a javascript on-click event handler will be generated * that opens a new window using the popup properties. */ private PopupSettings popupSettings = null; /** * Constructor. * * @param id * See Component * @param href * the href attribute to set * @param label * the label (body) */ public ExternalLink(final String id, final String href, final String label) { super(id); setDefaultModel(href != null ? new Model<>(href) : null); setBody(Model.of(label)); } /** * Constructor. * * @param id * The name of this component * @param href * the href attribute to set */ public ExternalLink(final String id, final String href) { this(id, Model.of(href)); } /** * Constructor. * * @param id * The name of this component * @param href * the href attribute to set */ public ExternalLink(final String id, final IModel<String> href) { this(id, href, null); } /** * Constructor. * * @param id * See Component * @param href * the href attribute to set * @param label * the label (body) */ public ExternalLink(final String id, final IModel<String> href, final IModel<?> label) { super(id); setDefaultModel(wrap(href)); setBody(label); } /** * Gets the popup specification. If not-null, a javascript on-click event handler will be * generated that opens a new window using the popup properties. * * @return the popup specification. */ public final PopupSettings getPopupSettings() { return popupSettings; } /** * Sets the popup specification. If not-null, a javascript on-click event handler will be * generated that opens a new window using the popup properties. * * @param popupSettings * the popup specification. * @return This */ public final ExternalLink setPopupSettings(final PopupSettings popupSettings) { this.popupSettings = popupSettings; return this; } /** * Processes the component tag. * * @param tag * Tag to modify * @see org.apache.wicket.Component#onComponentTag(org.apache.wicket.markup.ComponentTag) */ @Override protected void onComponentTag(final ComponentTag tag) { super.onComponentTag(tag); if (isEnabledInHierarchy() == false) { disableLink(tag); } else if (getDefaultModel() != null) { Object hrefValue = getDefaultModelObject(); if (hrefValue != null) { String url = hrefValue.toString(); if (contextRelative) { if (url.length() > 0 && url.charAt(0) == '/') { url = url.substring(1); } url = UrlUtils.rewriteToContextRelative(url, RequestCycle.get()); } // if the tag is an anchor proper if (tag.getName().equalsIgnoreCase("a") || tag.getName().equalsIgnoreCase("link") || tag.getName().equalsIgnoreCase("area")) { // generate the href attribute tag.put("href", url); // Add any popup script if (popupSettings != null) { // NOTE: don't encode to HTML as that is not valid // JavaScript tag.put("onclick", popupSettings.getPopupJavaScript()); } } else { // generate a popup script by asking popup settings for one if (popupSettings != null) { popupSettings.setTarget("'" + url + "'"); String popupScript = popupSettings.getPopupJavaScript(); tag.put("onclick", popupScript); } else { // or generate an onclick JS handler directly tag.put("onclick", "window.location.href='" + url + "';return false;"); } } } } } /** * @return True if this link is automatically prepended with ../ to make it relative to the * context root. */ public boolean isContextRelative() { return contextRelative; } /** * Set to true if this link should be automatically prepended with ../ to make it relative to * the context root. * * @param contextRelative * @return This for chaining */ public ExternalLink setContextRelative(final boolean contextRelative) { this.contextRelative = contextRelative; return this; } }