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 com.google.ratel.service.error; import com.google.ratel.RatelConfig; import com.google.ratel.deps.lang3.StringUtils; import com.google.ratel.service.json.JsonElement; import com.google.ratel.service.json.JsonService; import com.google.ratel.service.template.TemplateException; import com.google.ratel.util.HtmlStringBuffer; import com.google.ratel.core.Mode; import com.google.ratel.util.RatelUtils; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.LineNumberReader; import java.io.PrintWriter; import java.io.StringWriter; import java.lang.reflect.Method; import java.util.Enumeration; import java.util.Locale; import java.util.Map; import java.util.ResourceBundle; import java.util.StringTokenizer; import java.util.TreeMap; import javax.servlet.ServletException; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpSession; /** * Provides an HTML <div> error report for the display of page error information. This class is used by ErrorPage and ClickServlet for * the display of error information. */ public class ErrorReport { /** * The Java language keywords. Used to render Java source code. */ /* private static final String[] JAVA_KEYWORDS = { "package", "import", "enum", "class", "interface", "public", "protected", "private", "extends", "implements", "return", "if", "while", "for", "do", "else", "try", "new", "void", "catch", "throws", "throw", "static", "final", "break", "continue", "super", "finally", "true", "false", "true;", "false;", "null", "boolean", "int", "char", "long", "float", "double", "short" }; */ /** * The column number of the error, or -1 if not defined. */ protected int columnNumber; /** * The cause of the error. */ protected final Throwable error; /** * The line number of the error, or -1 if not defined. */ protected int lineNumber; /** * The error is Velocity parsing exception. */ protected final boolean isParseError; /** * The application mode indicator. */ protected final Mode mode; /** * The service class which caused the error. */ protected final Class<?> serviceClass; /** * The method which caused the error. */ protected final Method method; /** * The servlet request. */ protected final HttpServletRequest request; /** * The servlet context. */ protected final RatelConfig ratelConfig; /** * The name of the error source. */ protected final String sourceName; /** * The error source LineNumberReader. */ protected LineNumberReader sourceReader; // Constructor ------------------------------------------------------------ /** * Create a ErrorReport instance from the given error and page. * * @param error the cause of the error * @param pageClass the Page class which caused the error * @param isProductionMode the application is in "production" mode * @param request the page request * @param servletContext the servlet context */ public ErrorReport(Throwable throwable, Class<?> serviceClass, Method method, Mode mode, HttpServletRequest request, RatelConfig ratelConfig) { this.serviceClass = serviceClass; this.method = method; this.mode = mode; this.request = request; this.ratelConfig = ratelConfig; Throwable temp = getTemplateException(throwable); if (temp == null) { error = throwable; } else { error = temp; } if (isParseError(error)) { TemplateException te = (TemplateException) error; if (te.getTemplateName().charAt(0) == '/') { sourceName = te.getTemplateName(); } else { sourceName = '/' + te.getTemplateName(); } lineNumber = te.getLineNumber(); columnNumber = te.getColumnNumber(); InputStream is = ratelConfig.getServletContext().getResourceAsStream(sourceName); sourceReader = new LineNumberReader(new InputStreamReader(is)); isParseError = true; } else { isParseError = false; sourceName = null; columnNumber = -1; StringWriter sw = new StringWriter(); PrintWriter pw = new PrintWriter(sw); Throwable cause = getCause(); cause.printStackTrace(pw); StringTokenizer tokenizer = new StringTokenizer(sw.toString(), "\n"); try { tokenizer.nextToken(); String line = tokenizer.nextToken(); //if (cause instanceof IllegalArgumentException) { // line = tokenizer.nextToken(); //if (line.indexOf("org.apache.commons.lang.Validate") != -1) { // line = tokenizer.nextToken(); //} //} int nameStart = line.indexOf("at "); int nameEnd = line.indexOf("("); nameEnd = line.lastIndexOf(".", nameEnd); if (line.indexOf("$") != -1) { nameEnd = line.indexOf("$"); } if (nameStart != -1 && nameEnd != -1) { String classname = line.substring(nameStart + 3, nameEnd); int lineStart = line.indexOf(":"); if (lineStart != -1) { int lineEnd = line.indexOf(")"); if (lineEnd != -1) { String localLineNumber = line.substring(lineStart + 1, lineEnd); this.lineNumber = Integer.parseInt(localLineNumber); } String filename = "/" + classname.replace('.', '/') + ".java"; sourceReader = getJavaSourceReader(filename); } } } catch (Exception e) { e.printStackTrace(); } } } // Public Methods --------------------------------------------------------- /** * Return a error report HTML <div> element for the given error and page. The HTML <div> element 'id' and 'class' attribute * values are 'errorReport'. * * @return a error HTML display string */ @SuppressWarnings("unchecked") public String toString() { if (getMode() == Mode.PRODUCTION) { Locale locale = request.getLocale(); ResourceBundle bundle = RatelUtils.getBundle("ratel", locale); return bundle.getString("production-error-message"); } HtmlStringBuffer buffer = new HtmlStringBuffer(10 * 1024); Throwable cause = getCause(); buffer.append("<div id='errorReport' class='errorReport'>\n"); // Exception table buffer.append("<table class=\"flat-table flat-table-1\"><tbody>"); if (isParseError()) { buffer.append("<tr><th colspan='2' class='header'>Service Parsing Error</th></tr>"); buffer.append("<tr><th width='12%'>Source</th><td>"); buffer.append(getSourceName()); buffer.append("</td></tr>"); } else { buffer.append("<tr><th colspan='2' class='header'>Exception</th></tr>"); buffer.append("<tr><th width='12%'>Class</th><td>"); buffer.append(cause.getClass().getName()); buffer.append("</td></tr>"); } buffer.append("<tr><th valign='top' width='12%'>Message</th><td>"); buffer.append(getMessage()); buffer.append("</td></tr>"); if (getSourceReader() != null) { buffer.append("<tr><td class='pre' valign='top' colspan='2'>\n"); buffer.append(getRenderedSource()); buffer.append("</td></tr>"); } if (!isParseError()) { buffer.append("<tr><td valign='top' colspan='2' class='pre'>\n"); buffer.append(getStackTrace()); buffer.append("</td></tr>"); } buffer.append("</tbody></table>"); buffer.append("<br/>"); // Service table buffer.append("<table class=\"flat-table flat-table-1\"><tbody>"); buffer.append("<tr><th colspan='2' class='header'>Service</th></tr>"); buffer.append("<tr><th width='12%'>Service</th><td>"); if (serviceClass != null) { String location = RatelUtils.buildLocation(serviceClass, method); buffer.append(location); } buffer.append("</td></tr>"); buffer.append("<tr><th width='12%'>Path</th><td>"); buffer.append(RatelUtils.getResourcePath(request)); buffer.append("</td></tr>"); buffer.append("</tbody></table>"); buffer.append("<br/>"); // Request table buffer.append("<table class=\"flat-table flat-table-1\"><tbody>"); buffer.append("<tr><th colspan='2' class='header'>Request</th></tr>"); Map<String, Object> requestAttributes = new TreeMap<String, Object>(); Enumeration attributeNames = request.getAttributeNames(); while (attributeNames.hasMoreElements()) { String name = attributeNames.nextElement().toString(); requestAttributes.put(name, request.getAttribute(name)); } buffer.append("<tr><th width='12%' valign='top'>Attributes</th><td>"); writeMap(requestAttributes, buffer); buffer.append("</td></tr>"); buffer.append("<tr><th width='12%'>Auth Type</th><td>"); buffer.append(request.getAuthType()); buffer.append("</td></tr>"); buffer.append("<tr><th width='12%'>Context Path</th><td>"); buffer.append("<a href='"); buffer.append(request.getContextPath()); buffer.append("'>"); buffer.append(request.getContextPath()); buffer.append("</a>"); buffer.append("</td></tr>"); Map<String, Object> requestHeaders = new TreeMap<String, Object>(); Enumeration headerNames = request.getHeaderNames(); while (headerNames.hasMoreElements()) { String name = headerNames.nextElement().toString(); requestHeaders.put(name, request.getHeader(name)); } buffer.append("<tr><th width='12%' valign='top'>Headers</th><td>"); writeMap(requestHeaders, buffer); buffer.append("</td></tr>"); buffer.append("<tr><th width='12%'>Query</th><td>"); String escapedQueryString = RatelUtils.escape(request.getQueryString()); buffer.append(escapedQueryString); buffer.append("</td></tr>"); buffer.append("<tr><th width='12%'>Method</th><td>"); buffer.append(request.getMethod()); buffer.append("</td></tr>"); String content = null; if (RatelUtils.isPost(request) && RatelUtils.isJsonContentType(request)) { try { content = RatelUtils.getContent(request, ratelConfig.getMaxRequestSize()); } catch (Exception ignore) { } buffer.append("<tr><th width='12%' valign='top'>Json Request Content></th>"); buffer.append("<td class='pre'>"); if (StringUtils.isBlank(content)) { buffer.append( "Could not retrieve HttpServletRequest content from Reader, most likely because the content was already read before the exception occurred."); } else { buffer.append("<pre class='prettyprint'>"); String json = content; try { // Pretty format the json JsonService jsonService = ratelConfig.getJsonService(); JsonElement node = jsonService.parseJson(content); if (node != null) { json = jsonService.toJson(node); } } catch (Exception ignore) { } buffer.append(json); buffer.append("</pre>"); } buffer.append("</td></tr>"); } else { Map<String, Object> requestParams = new TreeMap<String, Object>(); Enumeration paramNames = request.getParameterNames(); while (paramNames.hasMoreElements()) { String name = paramNames.nextElement().toString(); requestParams.put(name, request.getParameter(name)); } buffer.append("<tr><th width='12%' valign='top'>Parameters</th><td>"); writeMap(requestParams, buffer); buffer.append("</td></tr>"); } buffer.append("<tr><th width='12%'>Remote User</th><td>"); buffer.append(request.getRemoteUser()); buffer.append("</td></tr>"); buffer.append("<tr><th width='12%' valign='top'URI</th><td>"); buffer.append("<a href='"); String requestURI = RatelUtils.getRequestURI(request); buffer.append(requestURI); buffer.append("'>"); buffer.append(requestURI); buffer.append("</a>"); buffer.append("</td></tr>"); buffer.append("<tr><th width='12%'>URL</th><td>"); buffer.append("<a href='"); buffer.append(request.getRequestURL()); buffer.append("'>"); buffer.append(request.getRequestURL()); buffer.append("</a>"); buffer.append("</td></tr>"); Map<String, Object> sessionAttributes = new TreeMap<String, Object>(); if (request.getSession(false) != null) { HttpSession session = request.getSession(); attributeNames = session.getAttributeNames(); while (attributeNames.hasMoreElements()) { String name = attributeNames.nextElement().toString(); sessionAttributes.put(name, session.getAttribute(name)); } } buffer.append("<tr><th width='12%' valign='top'>Session</th><td>"); writeMap(sessionAttributes, buffer); buffer.append("</td></tr>"); buffer.append("</tbody></table>\n"); buffer.append("</div>\n"); return buffer.toString(); } // Protected Methods ------------------------------------------------------ /** * Return the cause of the error. * * @return the cause of the error */ protected Throwable getCause() { Throwable cause = null; if (error instanceof ServletException) { cause = ((ServletException) error).getRootCause(); if (cause == null) { cause = error.getCause(); } } else { cause = getRootCause(error); } if (cause == null) { cause = error; } return cause; } protected Throwable getRootCause(Throwable error) { Throwable root = error; while (root.getCause() != null) { root = root.getCause(); } return root; } /** * Return the error source column number, or -1 if not determined. * * @return the error source column number, or -1 if not determined */ protected int getColumnNumber() { return columnNumber; } /** * Return true if the error was a Velocity parsing exception. * * @return true if the error was a Velocity parsing exception */ protected boolean isParseError() { return isParseError; } /** * Return the application mode. * * @return the application mode */ protected Mode getMode() { return mode; } /** * Return the error source line number, or -1 if not determined. * * @return the error source line number, or -1 if not determined */ protected int getLineNumber() { return lineNumber; } /** * Return the error message. * * @return the error message */ protected String getMessage() { if (isParseError()) { String message = error.getMessage(); String parseMsg = message; int startIndex = message.indexOf('\n'); int endIndex = message.lastIndexOf("..."); if (startIndex != -1 && endIndex > startIndex) { parseMsg = message.substring(startIndex + 1, endIndex); } parseMsg = RatelUtils.escapeHtml(parseMsg); parseMsg = StringUtils.replace(parseMsg, "...", ",  "); return parseMsg; } else { Throwable cause = getCause(); String value = (cause.getMessage() != null) ? cause.getMessage() : "null"; return RatelUtils.escapeHtml(value); } } /** * Return the error source name. * * @return the error source name */ protected String getSourceName() { return sourceName; } /** * Return a LineNumberReader for the error source file, or null if not defined. * * @return LineNumberReader for the error source file, or null if not defined */ protected LineNumberReader getSourceReader() { return sourceReader; } /** * Return Java Source LineNumberReader for the given filename, or null if not found. * * @param filename the name of the Java source file, e.g. /examples/Page.java * @return LineNumberReader for the given source filename, or null if not found * @throws FileNotFoundException if file could not be found */ protected LineNumberReader getJavaSourceReader(String filename) throws FileNotFoundException { if (serviceClass == null) { return null; } // Look for source file on classpath InputStream is = serviceClass.getResourceAsStream(filename); if (is != null) { return new LineNumberReader(new InputStreamReader(is)); } // Else search for source file under WEB-INF String rootPath = ratelConfig.getServletContext().getRealPath("/"); String webInfPath = rootPath + File.separator + "WEB-INF"; File sourceFile = null; File webInfDir = new File(webInfPath); if (webInfDir.isDirectory() && webInfDir.canRead()) { File[] dirList = webInfDir.listFiles(); if (dirList != null) { for (File file : dirList) { if (file.isDirectory() && file.canRead()) { String sourcePath = file.toString() + filename; sourceFile = new File(sourcePath); if (sourceFile.isFile() && sourceFile.canRead()) { FileInputStream fis = new FileInputStream(sourceFile); return new LineNumberReader(new InputStreamReader(fis)); } } } } } return null; } /** * Return a HTML rendered section of the source error with the error line highlighted. * * @return a HTML rendered section of the parsing error page template */ protected String getRenderedSource() { HtmlStringBuffer buffer = new HtmlStringBuffer(5 * 1024); buffer.append("<pre class='prettyprint'>"); if (sourceReader == null) { buffer.append("Source is not available.</span>"); return buffer.toString(); } final String errorLineStyle = "style='background-color:yellow;'"; final String errorCharSpan = "<span style='color:red;text-decoration:underline;font-weight:bold;'>"; try { String line = sourceReader.readLine(); while (line != null) { if (skipLine()) { line = sourceReader.readLine(); continue; } boolean isErrorLine = sourceReader.getLineNumber() == lineNumber; // Start div tag buffer.append("<div "); if (isErrorLine) { buffer.append(errorLineStyle); } buffer.append(">"); // Write out line number String lineStr = "" + sourceReader.getLineNumber(); int numberSpace = 3 - lineStr.length(); for (int i = 0; i < numberSpace; i++) { buffer.append(" "); } if (isErrorLine) { buffer.append("<b>"); } buffer.append(sourceReader.getLineNumber()); if (isErrorLine) { buffer.append("</b>"); } buffer.append(": "); // Write out line content if (isErrorLine) { if (isParseError()) { HtmlStringBuffer htmlLine = new HtmlStringBuffer(line.length() * 2); for (int i = 0; i < line.length(); i++) { if (i == getColumnNumber() - 1) { htmlLine.append(errorCharSpan); htmlLine.append(line.charAt(i)); htmlLine.append("</span>"); } else { htmlLine.append(line.charAt(i)); } } buffer.append(htmlLine.toString()); } else { line = RatelUtils.escapeHtml(line); buffer.append(line); } } else { if (isParseError()) { buffer.append(RatelUtils.escapeHtml(line)); } else { line = RatelUtils.escapeHtml(line); buffer.append(line); } } // Close div tag buffer.append("</div>"); line = sourceReader.readLine(); } } catch (IOException ioe) { buffer.append("Could not load page source: "); buffer.append(RatelUtils.escapeHtml(ioe.toString())); } finally { try { sourceReader.close(); } catch (IOException ioe) { // do nothing } } buffer.append("</pre>"); return buffer.toString(); } /** * Return a HTML encode stack trace string from the given error. * * @return a HTML encode stack trace string. */ protected String getStackTrace() { StringWriter sw = new StringWriter(); PrintWriter pw = new PrintWriter(sw); getCause().printStackTrace(pw); HtmlStringBuffer buffer = new HtmlStringBuffer(sw.toString().length() + 80); buffer.append("<pre>"); buffer.append(RatelUtils.escapeHtml(sw.toString().trim())); buffer.append("</pre>"); return buffer.toString(); } /** * Write out the map name value pairs as name=value lines to the string buffer. * * @param map the Map of name value pairs * @param buffer the string buffer to write out the values to */ protected void writeMap(Map<String, Object> map, HtmlStringBuffer buffer) { for (Map.Entry<String, Object> entry : map.entrySet()) { String key = entry.getKey(); Object value = entry.getValue(); buffer.append(key); buffer.append("="); if (value != null) { buffer.append(RatelUtils.escapeHtml(value.toString())); } else { buffer.append("null"); } buffer.append("<br/>"); } if (map.isEmpty()) { buffer.append(" "); } } /** * Return a HTML rendered Java source line with keywords highlighted using the given line. * * @param line the Java source line to render * @return HTML rendered Java source line */ /* protected String getRenderJavaLine(String line) { line = RatelUtils.escapeHtml(line); for (String keyword : JAVA_KEYWORDS) { line = renderJavaKeywords(line, keyword); } return line; }*/ /** * Render the HTML rendered Java source line with the given keyword highlighted. * * @param line the given Java source line to render * @param keyword the Java keyword to highlight * @return the HTML rendered Java source line with the given keyword highlighted */ /* protected String renderJavaKeywords(String line, String keyword) { String markupToken = "<span style='color:#7f0055;font-weight:bold;'>" + keyword + "</span>"; line = StringUtils.replace(line, " " + keyword + " ", " " + markupToken + " "); if (line.startsWith(keyword)) { line = markupToken + line.substring(keyword.length()); } if (line.endsWith(keyword)) { line = line.substring(0, line.length() - keyword.length()) + markupToken; } return line; }*/ /** * Return true if the current line read from the source line reader, should be skipped, or false if the current line should be rendered. * * @return true if the current line from the source reader should be skipped */ protected boolean skipLine() { final int currentLine = getSourceReader().getLineNumber(); final int errorLine = getLineNumber(); if (Math.abs(currentLine - errorLine) <= 10) { return false; } else { return true; } } protected boolean isParseError(Throwable error) { if (error instanceof TemplateException) { TemplateException te = (TemplateException) error; return te.isParseError(); } return false; } protected Throwable getTemplateException(Throwable error) { if (error instanceof TemplateException) { return error; } Throwable root = error; while (root.getCause() != null) { root = root.getCause(); if (root instanceof TemplateException) { return root; } } return root; } }