Java tutorial
/* * Copyright 2018-present Open Networking 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.onosproject.netconf; import static org.slf4j.LoggerFactory.getLogger; import java.io.IOException; import javax.xml.bind.JAXBContext; import javax.xml.bind.JAXBElement; import javax.xml.bind.JAXBException; import javax.xml.bind.Unmarshaller; import javax.xml.namespace.QName; import javax.xml.stream.XMLEventReader; import javax.xml.stream.XMLInputFactory; import javax.xml.stream.XMLStreamException; import javax.xml.stream.XMLStreamReader; import javax.xml.transform.OutputKeys; import javax.xml.transform.Source; import javax.xml.transform.Transformer; import javax.xml.transform.TransformerException; import javax.xml.transform.TransformerFactory; import javax.xml.transform.dom.DOMSource; import javax.xml.transform.stax.StAXSource; import javax.xml.transform.stream.StreamResult; import org.onosproject.netconf.rpc.RpcErrorType; import org.slf4j.Logger; import org.w3c.dom.Node; import com.google.common.annotations.Beta; import com.google.common.io.CharSource; import com.google.common.io.CharStreams; @Beta public final class NetconfRpcParserUtil { private static final Logger log = getLogger(NetconfRpcParserUtil.class); /** * Parse first rpc-reply contained in the input. * * @param xml input * @return {@link NetconfRpcReply} or null on error */ public static NetconfRpcReply parseRpcReply(CharSequence xml) { XMLInputFactory xif = XMLInputFactory.newFactory(); try { XMLStreamReader xsr = xif.createXMLStreamReader(CharSource.wrap(xml).openStream()); return parseRpcReply(xsr); } catch (XMLStreamException | IOException e) { log.error("Exception thrown creating XMLStreamReader", e); return null; } } /** * Parse first rpc-reply contained in the input. * * @param xsr input * @return {@link NetconfRpcReply} or null on error */ public static NetconfRpcReply parseRpcReply(XMLStreamReader xsr) { try { for (; xsr.hasNext(); xsr.next()) { if (xsr.isStartElement() && xsr.getName().getLocalPart().equals("rpc-reply")) { NetconfRpcReply.Builder builder = NetconfRpcReply.builder(); String msgId = xsr.getAttributeValue(null, "message-id"); builder.withMessageId(msgId); xsr.nextTag(); return parseRpcReplyBody(builder, xsr); } } } catch (XMLStreamException e) { log.error("Exception thrown parsing rpc-reply", e); } return null; } private static NetconfRpcReply parseRpcReplyBody(NetconfRpcReply.Builder builder, XMLStreamReader xsr) { try { for (; xsr.hasNext(); xsr.next()) { if (xsr.isStartElement()) { switch (xsr.getName().getLocalPart()) { case "ok": try { // skip to end of tag event xsr.getElementText(); } catch (XMLStreamException e) { log.warn("Failed parsing ok", e); } // ok should be the only element return builder.buildOk(); case "rpc-error": try { JAXBContext context = JAXBContext.newInstance(RpcErrorType.class); Unmarshaller unmarshaller = context.createUnmarshaller(); JAXBElement<RpcErrorType> error = unmarshaller.unmarshal(xsr, RpcErrorType.class); builder.addError(NetconfRpcError.wrap(error.getValue())); } catch (JAXBException e) { log.warn("Failed parsing rpc-error", e); } break; default: // =rpc-response QName qName = xsr.getName(); try { TransformerFactory tf = TransformerFactory.newInstance(); Transformer t = tf.newTransformer(); t.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes"); StringBuilder sb = new StringBuilder(); t.transform(new StAXSource(xsr), new StreamResult(CharStreams.asWriter(sb))); builder.addResponses(sb.toString()); } catch (TransformerException e) { log.warn("Failed parsing {}", qName, e); } break; } } } } catch (XMLStreamException e) { log.error("Exception thrown parsing rpc-reply body", e); } return builder.build(); } /** * Converts XML object into a String. * * @param xml Object (e.g., DOM {@link Node}) * @return String representation of {@code xml} or empty on error. */ @Beta public static String toString(Object xml) { TransformerFactory tf = TransformerFactory.newInstance(); try { Transformer t = tf.newTransformer(); t.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes"); Source xmlSource = null; if (xml instanceof Node) { xmlSource = new DOMSource((Node) xml); } else if (xml instanceof XMLEventReader) { xmlSource = new StAXSource((XMLEventReader) xml); } else if (xml instanceof XMLStreamReader) { xmlSource = new StAXSource((XMLStreamReader) xml); } else { log.warn("Unknown XML object type: {}, {}", xml.getClass(), xml); return ""; } StringBuilder sb = new StringBuilder(); t.transform(xmlSource, new StreamResult(CharStreams.asWriter(sb))); return sb.toString(); } catch (TransformerException | XMLStreamException e) { log.error("Exception thrown", e); return ""; } } private NetconfRpcParserUtil() { } }