Java tutorial
/* * Jitsi, the OpenSource Java VoIP and Instant Messaging client. * * Copyright @ 2015 Atlassian Pty Ltd * * 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 net.java.sip.communicator.impl.gui.main.chat.replacers; import java.util.regex.*; import net.java.sip.communicator.impl.gui.main.chat.*; import org.apache.commons.lang3.*; /** * The URL replacer used for replacing identified URL's with variations that are * surrounded by A-tags (anchor tags). * * @author Danny van Heumen */ public class URLReplacer implements Replacer { /** * The URL pattern to be used in matching. */ private final Pattern pattern; /** * The URL Replacer. * * @param urlPattern the exact URL pattern to be applied */ public URLReplacer(final Pattern urlPattern) { if (urlPattern == null) { throw new IllegalArgumentException("urlPattern cannot be null"); } this.pattern = urlPattern; } /** * Plain text is expected. * * @return returns true for plain text expectation */ @Override public boolean expectsPlainText() { return true; } /** * Replace operation for replacing URL's with a hyperlinked version. * * @param target destination to write the replacement result to * @param piece the piece of content to be processed */ @Override public void replace(final StringBuilder target, final String piece) { final Matcher m = this.pattern.matcher(piece); int prevEnd = 0; while (m.find()) { target.append(StringEscapeUtils.escapeHtml4(piece.substring(prevEnd, m.start()))); prevEnd = m.end(); String url = m.group().trim(); target.append("<A href=\""); if (url.startsWith("www")) { target.append("http://"); } target.append(url); target.append("\">"); target.append(StringEscapeUtils.escapeHtml4(url)); target.append("</A>"); } target.append(StringEscapeUtils.escapeHtml4(piece.substring(prevEnd))); } }