restconf/restconf-nb/src/main/java/org/opendaylight/restconf/server/mdsal/streams/dtcl/XMLDataTreeCandidateFormatter.java

   1 /*
   2  * Copyright (c) 2020 PANTHEON.tech, s.r.o. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8 package org.opendaylight.restconf.server.mdsal.streams.dtcl;
   9
  10 import java.io.IOException;
  11 import java.io.StringWriter;
  12 import java.time.Instant;
  13 import java.util.List;
  14 import javax.xml.XMLConstants;
  15 import javax.xml.stream.XMLStreamException;
  16 import javax.xml.xpath.XPathExpressionException;
  17 import org.opendaylight.restconf.server.spi.TextParameters;
  18 import org.opendaylight.yangtools.yang.data.tree.api.DataTreeCandidate;
  19 import org.opendaylight.yangtools.yang.model.api.EffectiveModelContext;
  20
  21 final class XMLDataTreeCandidateFormatter extends DataTreeCandidateFormatter {
  22     private static final XMLDataTreeCandidateFormatter EMPTY = new XMLDataTreeCandidateFormatter(TextParameters.EMPTY);
  23
  24     static final DataTreeCandidateFormatterFactory FACTORY = new DataTreeCandidateFormatterFactory(EMPTY) {
  25         @Override
  26         public XMLDataTreeCandidateFormatter getFormatter(final TextParameters textParams, final String xpathFilter)
  27                 throws XPathExpressionException {
  28             return new XMLDataTreeCandidateFormatter(textParams, xpathFilter);
  29         }
  30
  31         @Override
  32         public XMLDataTreeCandidateFormatter newFormatter(final TextParameters textParams) {
  33             return new XMLDataTreeCandidateFormatter(textParams);
  34         }
  35     };
  36
  37     private XMLDataTreeCandidateFormatter(final TextParameters textParams) {
  38         super(textParams);
  39     }
  40
  41     private XMLDataTreeCandidateFormatter(final TextParameters textParams, final String xpathFilter)
  42             throws XPathExpressionException {
  43         super(textParams, xpathFilter);
  44     }
  45
  46     @Override
  47     protected String createText(final TextParameters params, final EffectiveModelContext schemaContext,
  48             final List<DataTreeCandidate> input, final Instant now) throws Exception {
  49         final var writer = new StringWriter();
  50         boolean nonEmpty = false;
  51         try {
  52             final var xmlStreamWriter = createStreamWriterWithNotification(writer, now);
  53             xmlStreamWriter.writeStartElement(XMLConstants.DEFAULT_NS_PREFIX, DATA_CHANGED_NOTIFICATION_ELEMENT,
  54                 DATA_CHANGED_NOTIFICATION_NS);
  55             xmlStreamWriter.writeDefaultNamespace(DATA_CHANGED_NOTIFICATION_NS);
  56
  57             final var serializer = new XMLDataTreeCandidateSerializer(schemaContext, xmlStreamWriter);
  58             for (var candidate : input) {
  59                 nonEmpty |= serializer.serialize(candidate, params);
  60             }
  61
  62             // data-changed-notification
  63             xmlStreamWriter.writeEndElement();
  64
  65             // notification
  66             xmlStreamWriter.writeEndElement();
  67             xmlStreamWriter.close();
  68         } catch (XMLStreamException e) {
  69             throw new IOException("Failed to write notification content", e);
  70         }
  71
  72         return nonEmpty ? writer.toString() : null;
  73     }
  74 }