Java tutorial
/* * Copyright 1999-2004 The Apache Software Foundation. * * 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.apache.cocoon.components.notification; import org.apache.avalon.framework.component.Component; import org.apache.commons.lang.SystemUtils; import org.apache.commons.lang.exception.ExceptionUtils; import org.xml.sax.SAXParseException; import javax.xml.transform.SourceLocator; import javax.xml.transform.TransformerException; import java.io.PrintWriter; import java.io.StringWriter; import java.io.Writer; import java.util.Map; /** * Generates an Notifying representation of widely used objects. * * @author <a href="mailto:nicolaken@apache.org">Nicola Ken Barozzi</a> * @author Marc Liyanage (futureLAB AG) * @version CVS $Id: DefaultNotifyingBuilder.java 280628 2005-09-13 19:14:35Z sylvain $ */ public class DefaultNotifyingBuilder implements NotifyingBuilder, Component { /** * Builds a Notifying object (SimpleNotifyingBean in this case) * that tries to explain what the Object o can reveal. * * @param sender who sent this Object. * @param o the object to use when building the SimpleNotifyingBean * @return the Notifying Object that was build * @see org.apache.cocoon.components.notification.Notifying */ public Notifying build(Object sender, Object o) { if (o instanceof Notifying) { return (Notifying) o; } else if (o instanceof Throwable) { Throwable t = (Throwable) o; SimpleNotifyingBean n = new SimpleNotifyingBean(sender); n.setType(Notifying.ERROR_NOTIFICATION); n.setTitle("An Error Occurred"); if (t != null) { Throwable rootCause = getRootCause(t); n.setSource(t.getClass().getName()); // NullPointerException usually does not have a message if (rootCause.getMessage() != null) { n.setMessage(rootCause.getMessage()); } else { n.setMessage(t.getMessage()); } n.setDescription(t.toString()); n.addExtraDescription(Notifying.EXTRA_CAUSE, rootCause.toString()); if (rootCause instanceof SAXParseException) { SAXParseException saxParseException = (SAXParseException) rootCause; n.addExtraDescription(Notifying.EXTRA_LOCATION, String.valueOf(saxParseException.getSystemId())); n.addExtraDescription(Notifying.EXTRA_LINE, String.valueOf(saxParseException.getLineNumber())); n.addExtraDescription(Notifying.EXTRA_COLUMN, String.valueOf(saxParseException.getColumnNumber())); } else if (rootCause instanceof TransformerException) { TransformerException transformerException = (TransformerException) rootCause; SourceLocator sourceLocator = transformerException.getLocator(); if (null != sourceLocator) { n.addExtraDescription(Notifying.EXTRA_LOCATION, String.valueOf(sourceLocator.getSystemId())); n.addExtraDescription(Notifying.EXTRA_LINE, String.valueOf(sourceLocator.getLineNumber())); n.addExtraDescription(Notifying.EXTRA_COLUMN, String.valueOf(sourceLocator.getColumnNumber())); } } // Add root cause exception stacktrace StringWriter sw = new StringWriter(); rootCause.printStackTrace(new PrintWriter(sw)); n.addExtraDescription(Notifying.EXTRA_STACKTRACE, sw.toString()); // Add full exception chain sw = new StringWriter(); appendTraceChain(sw, t); n.addExtraDescription(Notifying.EXTRA_FULLTRACE, sw.toString()); } return n; } else { SimpleNotifyingBean n = new SimpleNotifyingBean(sender); n.setType(Notifying.UNKNOWN_NOTIFICATION); n.setTitle("Object Notification"); n.setMessage(String.valueOf(o)); n.setDescription("No details available."); return n; } } /** * Builds a Notifying object (SimpleNotifyingBean in this case) * that explains a notification. * * @param sender who sent this Object. * @param o the object to use when building the SimpleNotifyingBean * @param type see the Notifying apidocs * @param title see the Notifying apidocs * @param source see the Notifying apidocs * @param message see the Notifying apidocs * @param description see the Notifying apidocs * @param extra see the Notifying apidocs * @return the Notifying Object that was build * @see org.apache.cocoon.components.notification.Notifying */ public Notifying build(Object sender, Object o, String type, String title, String source, String message, String description, Map extra) { // NKB Cast here is secure, the method is of this class SimpleNotifyingBean n = (SimpleNotifyingBean) build(sender, o); if (type != null) n.setType(type); if (title != null) n.setTitle(title); if (source != null) n.setSource(source); if (message != null) n.setMessage(message); if (description != null) n.setDescription(description); if (extra != null) n.addExtraDescriptions(extra); return n; } /** * Print stacktrace of the Throwable and stacktraces of its all nested causes into a Writer. */ private static void appendTraceChain(Writer out, Throwable t) { PrintWriter pw = new PrintWriter(out); if (SystemUtils.isJavaVersionAtLeast(140)) { t.printStackTrace(pw); } else { for (Throwable cause = t; cause != null; cause = ExceptionUtils.getCause(cause)) { if (cause != t) { pw.println(); } cause.printStackTrace(pw); } } } /** * Get root cause Throwable. */ public static Throwable getRootCause(Throwable t) { Throwable rootCause = ExceptionUtils.getRootCause(t); return rootCause != null ? rootCause : t; } }