Java tutorial
//$HeadURL$ /*---------------------------------------------------------------------------- This file is part of deegree, http://deegree.org/ Copyright (C) 2001-2009 by: Department of Geography, University of Bonn and lat/lon GmbH This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA Contact information: lat/lon GmbH Aennchenstr. 19, 53177 Bonn Germany http://lat-lon.de/ Department of Geography, University of Bonn Prof. Dr. Klaus Greve Postfach 1147, 53001 Bonn Germany http://www.geographie.uni-bonn.de/deegree/ e-mail: info@deegree.org ----------------------------------------------------------------------------*/ package org.deegree.portal.owswatch.validator; import java.io.BufferedReader; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import javax.servlet.http.HttpServletResponse; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.ParserConfigurationException; import org.apache.commons.httpclient.HttpMethodBase; import org.deegree.framework.log.ILogger; import org.deegree.framework.log.LoggerFactory; import org.deegree.framework.util.StringTools; import org.deegree.framework.xml.XMLParsingException; import org.deegree.framework.xml.XMLTools; import org.w3c.dom.Document; import org.deegree.portal.owswatch.Status; import org.deegree.portal.owswatch.ValidatorResponse; /** * Abstract class implementing the method validate. * * @author <a href="mailto:elmasry@lat-lon.de">Moataz Elmasry</a> * @author last edited by: $Author$ * * @version $Revision$, $Date$ */ public abstract class AbstractValidator implements Validator { private static final ILogger LOG = LoggerFactory.getLogger(AbstractValidator.class); /* * (non-Javadoc) * * @see org.deegree.portal.owswatch.validator.Validator#validateAnswer(org.apache.commons.httpclient.HttpMethodBase, int, * int) */ public ValidatorResponse validateAnswer(HttpMethodBase method, int statusCode) { if (isValidHttpResponse(statusCode)) { return validateXml(method); } else { return validateErrorHttpResponse(statusCode); } } /** * Validates the HttpMethodBase and checks if the execution was successful or not * * @param method * the httpmethod after executing it * @return an instance of ValidatorResponse with the necessary information after validation */ protected ValidatorResponse validateXml(HttpMethodBase method) { String lastMessage = null; Status status = null; String contentType = method.getResponseHeader("Content-Type").getValue(); if (!contentType.contains("xml")) { status = Status.RESULT_STATE_UNEXPECTED_CONTENT; lastMessage = StringTools.concat(100, "Error: Response Content is ", contentType, " not xml"); return new ValidatorResponse(lastMessage, status); } String xml = null; try { InputStream stream = copyStream(method.getResponseBodyAsStream()); stream.reset(); xml = parseStream(stream); } catch (IOException e) { status = Status.RESULT_STATE_BAD_RESPONSE; lastMessage = status.getStatusMessage(); return new ValidatorResponse(lastMessage, status); } if (xml.length() == 0) { status = Status.RESULT_STATE_BAD_RESPONSE; lastMessage = "Error: XML Response is empty"; return new ValidatorResponse(lastMessage, status); } if (xml.contains("ServiceException")) { return validateXmlServiceException(method); } // If its an xml, and there's no service exception, then don't really parse the xml, // we assume that its well formed, since there might be huge xmls, which would take time to be parsed status = Status.RESULT_STATE_AVAILABLE; lastMessage = status.getStatusMessage(); return new ValidatorResponse(lastMessage, status); } /** * This method is called To read the ServiceExceptionReport from the xml file * * @param method * the httpmethod after executing it * @return an instance of ValidatorResponse with the necessary information after validation */ protected ValidatorResponse validateXmlServiceException(HttpMethodBase method) { Document doc = null; String lastMessage = null; Status status = null; try { InputStream stream = method.getResponseBodyAsStream(); stream.reset(); doc = instantiateParser().parse(stream); } catch (Exception e) { status = Status.RESULT_STATE_INVALID_XML; lastMessage = "Error: MalFormed XML Response"; return new ValidatorResponse(lastMessage, status); } try { status = Status.RESULT_STATE_SERVICE_UNAVAILABLE; lastMessage = XMLTools.getNodeAsString(doc.getDocumentElement(), "./ServiceException", null, "Service Unavailable. Unknown error"); return new ValidatorResponse(lastMessage, status); } catch (XMLParsingException e) { status = Status.RESULT_STATE_SERVICE_UNAVAILABLE; lastMessage = status.getStatusMessage(); return new ValidatorResponse(lastMessage, status); } } /** * Makes sure that the HttpResponse is not a critical error * * @param statusCode */ protected boolean isValidHttpResponse(int statusCode) { if (statusCode >= 100 && statusCode < 400) { return true; } return false; } /** * @param statusCode * @return instance of the validatorresponse with the error */ protected ValidatorResponse validateErrorHttpResponse(int statusCode) { String lastMessage = null; Status status = null; if (statusCode == HttpServletResponse.SC_REQUEST_TIMEOUT) { status = Status.RESULT_STATE_TIMEOUT; lastMessage = status.getStatusMessage(); } else { status = Status.RESULT_STATE_PAGE_UNAVAILABLE; lastMessage = status.getStatusMessage(); } return new ValidatorResponse(lastMessage, status); } /** * Parses a given InputStream to a String * * @param stream * @return String * @throws IOException */ protected String parseStream(InputStream stream) throws IOException { stream.reset(); InputStreamReader reader = new InputStreamReader(stream); BufferedReader bufReader = new BufferedReader(reader); StringBuilder builder = new StringBuilder(); String line = null; line = bufReader.readLine(); while (line != null) { builder.append(line); line = bufReader.readLine(); } String answer = builder.toString(); return answer; } /** * Creates a new instance of DocumentBuilder * * @return DocumentBuilder * @throws IOException */ protected DocumentBuilder instantiateParser() throws IOException { DocumentBuilder parser = null; try { DocumentBuilderFactory fac = DocumentBuilderFactory.newInstance(); fac.setNamespaceAware(true); fac.setValidating(false); fac.setIgnoringElementContentWhitespace(false); parser = fac.newDocumentBuilder(); return parser; } catch (ParserConfigurationException e) { throw new IOException("Unable to initialize DocumentBuilder: " + e.getMessage()); } } protected boolean closeStream(InputStream stream) { try { stream.close(); } catch (IOException e) { LOG.logError(e.getLocalizedMessage()); return false; } return true; } /** * Creates a new copy of the given InputStream * * @param stream * @return InputStream * @throws IOException */ protected InputStream copyStream(InputStream stream) throws IOException { ByteArrayOutputStream out = new ByteArrayOutputStream(); int read; byte[] bs = new byte[16384]; while ((read = stream.read(bs)) != -1) { out.write(bs, 0, read); } return new ByteArrayInputStream(out.toByteArray()); } }