Java tutorial
/** * Copyright (c) Codice Foundation * * This 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 3 of the * License, or any later version. * * This program 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. A copy of the GNU Lesser General Public License * is distributed along with this program and can be found at * <http://www.gnu.org/licenses/lgpl.html>. * **/ package ddf.catalog.services.xsltlistener; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.Serializable; import java.net.URLConnection; import java.util.HashMap; import java.util.List; import java.util.Map; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.ParserConfigurationException; import javax.xml.transform.Source; import javax.xml.transform.Transformer; import javax.xml.transform.TransformerConfigurationException; import javax.xml.transform.TransformerException; import javax.xml.transform.dom.DOMSource; import javax.xml.transform.stream.StreamResult; import org.apache.commons.codec.binary.Base64; import org.joda.time.format.DateTimeFormatter; import org.joda.time.format.ISODateTimeFormat; import org.osgi.framework.Bundle; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.w3c.dom.DOMException; import org.w3c.dom.Document; import org.w3c.dom.Element; import org.w3c.dom.Node; import org.w3c.dom.ls.DOMImplementationLS; import org.w3c.dom.ls.LSSerializer; import ddf.catalog.data.BinaryContent; import ddf.catalog.data.Metacard; import ddf.catalog.data.Result; import ddf.catalog.operation.SourceResponse; import ddf.catalog.transform.CatalogTransformerException; import ddf.catalog.transform.QueryResponseTransformer; import ddf.util.XPathHelper; public class XsltResponseQueueTransformer extends AbstractXsltTransformer implements QueryResponseTransformer { private static final String GRAND_TOTAL = "grandTotal"; // private static final String XML_RESULTS_NAMESPACE = // "http://ddf/xslt-response-queue-transformer"; private static final String XML_RESULTS_NAMESPACE = null; protected static Logger LOGGER = LoggerFactory.getLogger(XsltResponseQueueTransformer.class); public XsltResponseQueueTransformer() { } public XsltResponseQueueTransformer(Bundle bundle, String xslFile) { super(bundle, xslFile); } @Override public ddf.catalog.data.BinaryContent transform(SourceResponse upstreamResponse, Map<String, Serializable> arguments) throws CatalogTransformerException { LOGGER.debug("Transforming ResponseQueue with XSLT tranformer"); long grandTotal = -1; try { DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); factory.setNamespaceAware(true); DocumentBuilder builder = factory.newDocumentBuilder(); Document doc = builder.newDocument(); Node resultsElement = doc.appendChild(createElement(doc, XML_RESULTS_NAMESPACE, "results", null)); // TODO use streaming XSLT, not DOM List<Result> results = upstreamResponse.getResults(); grandTotal = upstreamResponse.getHits(); for (Result result : results) { Metacard metacard = result.getMetacard(); String thisMetacard = metacard.getMetadata(); if (metacard != null && thisMetacard != null) { Element metacardElement = createElement(doc, XML_RESULTS_NAMESPACE, "metacard", null); if (metacard.getId() != null) { metacardElement .appendChild(createElement(doc, XML_RESULTS_NAMESPACE, "id", metacard.getId())); } if (metacard.getMetacardType().toString() != null) { metacardElement.appendChild(createElement(doc, XML_RESULTS_NAMESPACE, "type", metacard.getMetacardType().getName())); } if (metacard.getTitle() != null) { metacardElement.appendChild( createElement(doc, XML_RESULTS_NAMESPACE, "title", metacard.getTitle())); } if (result.getRelevanceScore() != null) { metacardElement.appendChild(createElement(doc, XML_RESULTS_NAMESPACE, "score", result.getRelevanceScore().toString())); } if (result.getDistanceInMeters() != null) { metacardElement.appendChild(createElement(doc, XML_RESULTS_NAMESPACE, "distance", result.getDistanceInMeters().toString())); } if (metacard.getSourceId() != null) { metacardElement.appendChild( createElement(doc, XML_RESULTS_NAMESPACE, "site", metacard.getSourceId())); } if (metacard.getContentTypeName() != null) { String contentType = metacard.getContentTypeName(); Element typeElement = createElement(doc, XML_RESULTS_NAMESPACE, "content-type", contentType); // TODO revisit what to put in the qualifier typeElement.setAttribute("qualifier", "content-type"); metacardElement.appendChild(typeElement); } if (metacard.getResourceURI() != null) { try { metacardElement.appendChild(createElement(doc, XML_RESULTS_NAMESPACE, "product", metacard.getResourceURI().toString())); } catch (DOMException e) { LOGGER.warn(" Unable to create resource uri element", e); } } if (metacard.getThumbnail() != null) { metacardElement.appendChild(createElement(doc, XML_RESULTS_NAMESPACE, "thumbnail", Base64.encodeBase64String(metacard.getThumbnail()))); try { String mimeType = URLConnection .guessContentTypeFromStream(new ByteArrayInputStream(metacard.getThumbnail())); metacardElement .appendChild(createElement(doc, XML_RESULTS_NAMESPACE, "t_mimetype", mimeType)); } catch (IOException e) { // TODO Auto-generated catch block metacardElement.appendChild( createElement(doc, XML_RESULTS_NAMESPACE, "t_mimetype", "image/png")); } } DateTimeFormatter fmt = ISODateTimeFormat.dateTime(); if (metacard.getCreatedDate() != null) { metacardElement.appendChild(createElement(doc, XML_RESULTS_NAMESPACE, "created", fmt.print(metacard.getCreatedDate().getTime()))); } // looking at the date last modified if (metacard.getModifiedDate() != null) { metacardElement.appendChild(createElement(doc, XML_RESULTS_NAMESPACE, "updated", fmt.print(metacard.getModifiedDate().getTime()))); } if (metacard.getEffectiveDate() != null) { metacardElement.appendChild(createElement(doc, XML_RESULTS_NAMESPACE, "effective", fmt.print(metacard.getEffectiveDate().getTime()))); } if (metacard.getLocation() != null) { metacardElement.appendChild( createElement(doc, XML_RESULTS_NAMESPACE, "location", metacard.getLocation())); } Element documentElement = doc.createElementNS(XML_RESULTS_NAMESPACE, "document"); metacardElement.appendChild(documentElement); resultsElement.appendChild(metacardElement); Node importedNode = doc.importNode(new XPathHelper(thisMetacard).getDocument().getFirstChild(), true); documentElement.appendChild(importedNode); } else { LOGGER.debug("Null content/document returned to XSLT ResponseQueueTransformer"); continue; } } if (LOGGER.isDebugEnabled()) { DOMImplementationLS domImplementation = (DOMImplementationLS) doc.getImplementation(); LSSerializer lsSerializer = domImplementation.createLSSerializer(); LOGGER.debug("Generated XML input for transform: " + lsSerializer.writeToString(doc)); } LOGGER.debug("Starting responsequeue xslt transform."); Transformer transformer; Map<String, Object> mergedMap = new HashMap<String, Object>(); mergedMap.put(GRAND_TOTAL, grandTotal); if (arguments != null) { mergedMap.putAll(arguments); } BinaryContent resultContent; StreamResult resultOutput = null; Source source = new DOMSource(doc); ByteArrayOutputStream baos = new ByteArrayOutputStream(); resultOutput = new StreamResult(baos); try { transformer = templates.newTransformer(); } catch (TransformerConfigurationException tce) { throw new CatalogTransformerException("Could not perform Xslt transform: " + tce.getException(), tce.getCause()); } if (mergedMap != null && !mergedMap.isEmpty()) { for (Map.Entry<String, Object> entry : mergedMap.entrySet()) { if (LOGGER.isDebugEnabled()) { LOGGER.debug( "Adding parameter to transform {" + entry.getKey() + ":" + entry.getValue() + "}"); } transformer.setParameter(entry.getKey(), entry.getValue()); } } try { transformer.transform(source, resultOutput); byte[] bytes = baos.toByteArray(); LOGGER.debug("Transform complete."); resultContent = new XsltTransformedContent(bytes, mimeType); } catch (TransformerException te) { LOGGER.error("Could not perform Xslt transform: " + te.getException(), te.getCause()); throw new CatalogTransformerException("Could not perform Xslt transform: " + te.getException(), te.getCause()); } finally { // transformer.reset(); // don't need to do that unless we are putting it back into a // pool -- which we should do, but that can wait until later. } return resultContent; } catch (ParserConfigurationException e) { LOGGER.warn("Error creating new document: " + e.getMessage(), e.getCause()); throw new CatalogTransformerException("Error merging entries to xml feed.", e); } } private Element createElement(Document parentDoc, String namespace, String tagName, String elementValue) { Element element = parentDoc.createElementNS(namespace, tagName); element.setTextContent(elementValue); return element; } }