Java tutorial
/* * Copyright 2005 Joe Walker * * 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 org.directwebremoting.servlet; import java.io.IOException; import java.io.PrintWriter; import java.lang.reflect.Field; import java.lang.reflect.Modifier; import java.util.Collection; import java.util.HashMap; import java.util.Iterator; import java.util.Map; import java.util.SortedMap; import java.util.TreeMap; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.directwebremoting.Container; import org.directwebremoting.WebContext; import org.directwebremoting.WebContextFactory; import org.directwebremoting.extend.Handler; import org.directwebremoting.util.LocalUtil; import org.directwebremoting.util.MimeConstants; /** * A monitoring system so we can see what is going on inside DWR * @author Joe Walker [joe at getahead dot ltd dot uk] */ public class MonitorHandler implements Handler { /* (non-Javadoc) * @see org.directwebremoting.extend.Handler#handle(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse) */ public void handle(HttpServletRequest request, HttpServletResponse response) throws IOException { if (!debug) { log.warn( "Failed attempt to access test pages outside of debug mode. Set the debug init-parameter to true to enable."); throw new SecurityException("Access to debug pages is denied."); } response.setContentType(MimeConstants.MIME_HTML); PrintWriter out = response.getWriter(); out.print("<html><head><title>DWR - System Monitor</title></head><body>"); WebContext webContext = WebContextFactory.get(); out.print("<h1>DWR - System Monitor</h1>"); out.print("<h2>Global Settings:</h2>"); String contextPath = webContext.getContextPath(); out.print("<p>ContextPath: " + contextPath + "</p>"); out.print("<p>Current Page: " + webContext.getCurrentPage() + "</p>"); //ScriptSession scriptSession = webContext.getScriptSession(); Container container = webContext.getContainer(); SortedMap<String, Object> beans = new TreeMap<String, Object>(); SortedMap<String, String> settings = new TreeMap<String, String>(); SortedMap<String, String> urls = new TreeMap<String, String>(); for (String name : container.getBeanNames()) { Object bean = container.getBean(name); if (name.startsWith("url:")) { urls.put(name.substring(4), bean.getClass().getName()); } else if (bean instanceof String) { settings.put(name, bean.toString()); } else { beans.put(name, bean); } } // Add all the beans to an ID map for <a name=ID> IdManager ids = new IdManager(); // Remove the URL re-writers from the Settings map for (Map.Entry<String, String> urlEntry : urls.entrySet()) { for (Iterator<Map.Entry<String, String>> it = settings.entrySet().iterator(); it.hasNext();) { Map.Entry<String, String> settingEntry = it.next(); if (urlEntry.getKey().equals(settingEntry.getValue())) { it.remove(); urls.put(urlEntry.getKey(), urlEntry.getValue() + " (" + settingEntry.getKey() + ")"); } } } out.print("<h2>Beans:</h2>"); for (Map.Entry<String, Object> entry : beans.entrySet()) { String name = entry.getKey(); Object object = entry.getValue(); digWhatever(out, ids, name, object); } out.print("<h2>Settings:</h2>"); for (Map.Entry<String, String> entry : settings.entrySet()) { out.print("<p>" + entry.getKey() + ": \"" + entry.getValue() + "\"</p>"); } out.print("<h2>URLs:</h2>"); String prefix = contextPath + webContext.getHttpServletRequest().getServletPath(); for (Map.Entry<String, String> entry : urls.entrySet()) { out.print("<p><a href='" + prefix + entry.getKey() + "'>" + entry.getKey() + "</a>: " + entry.getValue() + "</p>"); } webContext.getContextPath(); out.print("</body></html>"); } /** * @param out * @param ids * @param name * @param object */ private void digWhatever(PrintWriter out, IdManager ids, String name, Object object) { if (object == null || object instanceof Number || object instanceof Boolean) { digSimple(out, name, object); } else if (object instanceof Collection<?>) { Collection<?> collection = (Collection<?>) object; boolean simple = true; for (Object child : collection) { if (!(child instanceof Number) && !(child instanceof Boolean) && !(child instanceof String)) { simple = false; } } if (simple) { digSimple(out, name, object); } else { digCollection(out, ids, name, collection); } } else if (object instanceof Map<?, ?>) { digMap(out, ids, name, (Map<?, ?>) object); } else if (object.getClass().getName().startsWith("java") || object.getClass().getName().startsWith("com.sun")) { digSimple(out, name, object); } else if (object instanceof String) { digString(out, name, (String) object); } else { digObject(out, ids, name, object); } } /** * @param out * @param name * @param object */ private void digSimple(PrintWriter out, String name, Object object) { out.print("<div class='section'>"); out.print("<div class='title'>" + name + ": " + object.toString() + "</div>"); out.print("</div>"); } /** * @param out * @param name * @param object */ private void digString(PrintWriter out, String name, String object) { out.print("<div class='section'>"); out.print("<div class='title'>" + name + ": \"" + object + "\"</div>"); out.print("</div>"); } /** * */ private void digCollection(PrintWriter out, IdManager ids, String name, Collection<?> collection) { out.print("<div class='section'>"); String id = ids.getIfExists(collection); if (id != null) { out.print("<div class='title'>" + name + ": <a href='#id" + id + "'>Map</a></div>"); } else { id = ids.allocate(collection); out.print("<div class='title'><a name='id" + id + "'>" + name + "</a>: Map</div>"); out.print("<ul>"); int i = 0; for (Object entry : collection) { digWhatever(out, ids, "" + i, entry.toString()); i++; } out.print("</ul>"); } } /** * */ private void digMap(PrintWriter out, IdManager ids, String name, Map<?, ?> map) { out.print("<div class='section'>"); String id = ids.getIfExists(map); if (id != null) { out.print("<div class='title'>" + name + ": <a href='#id" + id + "'>Map</a></div>"); } else { id = ids.allocate(map); out.print("<div class='title'><a name='id" + id + "'>" + name + "</a>: Map</div>"); out.print("<ul>"); for (Map.Entry<?, ?> entry : map.entrySet()) { Object value = entry.getValue(); digWhatever(out, ids, entry.getValue().toString(), value); } out.print("</ul>"); } } /** * */ private void digException(PrintWriter out, String name, Throwable ex) { out.print("<div class='section'>"); out.print("<div class='title'>" + name + ": " + ex.getClass().getSimpleName() + "(" + ex.getMessage() + ")</div>"); out.print("</div>"); } /** * */ private void digObject(PrintWriter out, IdManager ids, String name, Object object) { Class<?> type = object.getClass(); if (object instanceof Log) { return; } out.print("<div class='section'>"); String id = ids.getIfExists(object); if (id != null) { out.print("<div class='title'>" + name + ": <a href='#id" + id + "'>" + type.getSimpleName() + "</a></div>"); } else { id = ids.allocate(object); out.print("<div class='title'><a name='id" + id + "'>" + name + "</a>: " + type.getName() + "</div>"); out.print("<ul>"); for (Field field : LocalUtil.getAllFields(type)) { try { if (Modifier.isStatic(field.getModifiers())) { continue; } field.setAccessible(true); Object value = field.get(object); digWhatever(out, ids, field.getName(), value); } catch (Exception ex) { digException(out, field.getName(), ex); } } out.print("</ul>"); } } protected static class IdManager { /** * */ public String getIfExists(Object object) { return allocated.get(object); } protected String allocate(Object object) { if (allocated.containsKey(object)) { throw new IllegalStateException("object already exists"); } String id = "id" + nextId; nextId++; allocated.put(object, id); return id; } private int nextId; private Map<Object, String> allocated = new HashMap<Object, String>(); } /** * Set the debug status * @param debug The new debug setting */ public void setDebug(boolean debug) { this.debug = debug; } /** * Are we in debug mode? */ protected boolean debug = false; /** * The log stream */ private static final Log log = LogFactory.getLog(MonitorHandler.class); }