restconf/restconf-nb/src/main/java/org/opendaylight/restconf/server/mdsal/streams/dtcl/JSONDataTreeCandidateFormatter.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 com.google.gson.stream.JsonWriter;
  11 import java.io.IOException;
  12 import java.io.StringWriter;
  13 import java.time.Instant;
  14 import java.util.List;
  15 import javax.xml.xpath.XPathExpressionException;
  16 import org.eclipse.jdt.annotation.NonNull;
  17 import org.opendaylight.restconf.server.spi.TextParameters;
  18 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.controller.md.sal.remote.rev140114.DataChangedNotification;
  19 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.controller.md.sal.remote.rev140114.data.changed.notification.DataChangeEvent;
  20 import org.opendaylight.yang.svc.v1.urn.opendaylight.params.xml.ns.yang.controller.md.sal.remote.rev140114.YangModuleInfoImpl;
  21 import org.opendaylight.yangtools.yang.data.tree.api.DataTreeCandidate;
  22 import org.opendaylight.yangtools.yang.model.api.EffectiveModelContext;
  23
  24 final class JSONDataTreeCandidateFormatter extends DataTreeCandidateFormatter {
  25     private static final @NonNull String DATA_CHANGED_EVENT_NAME = DataChangeEvent.QNAME.getLocalName();
  26     private static final @NonNull String DATA_CHANGED_NOTIFICATION_NAME =
  27         YangModuleInfoImpl.getInstance().getName().getLocalName() + ":" + DataChangedNotification.QNAME.getLocalName();
  28     private static final JSONDataTreeCandidateFormatter EMPTY =
  29         new JSONDataTreeCandidateFormatter(TextParameters.EMPTY);
  30
  31     static final DataTreeCandidateFormatterFactory FACTORY = new DataTreeCandidateFormatterFactory(EMPTY) {
  32         @Override
  33         public DataTreeCandidateFormatter newFormatter(final TextParameters textParams) {
  34             return new JSONDataTreeCandidateFormatter(textParams);
  35         }
  36
  37         @Override
  38         public DataTreeCandidateFormatter getFormatter(final TextParameters textParams, final String xpathFilter)
  39                 throws XPathExpressionException {
  40             return new JSONDataTreeCandidateFormatter(textParams, xpathFilter);
  41         }
  42     };
  43
  44     private JSONDataTreeCandidateFormatter(final TextParameters textParams) {
  45         super(textParams);
  46     }
  47
  48     private JSONDataTreeCandidateFormatter(final TextParameters textParams, final String xpathFilter)
  49             throws XPathExpressionException {
  50         super(textParams, xpathFilter);
  51     }
  52
  53     @Override
  54     protected String createText(final TextParameters params, final EffectiveModelContext schemaContext,
  55             final List<DataTreeCandidate> input, final Instant now) throws IOException {
  56         try (var writer = new StringWriter()) {
  57             boolean nonEmpty = false;
  58             try (var jsonWriter = new JsonWriter(writer)) {
  59                 jsonWriter.beginObject()
  60                     .name("ietf-restconf:notification").beginObject()
  61                         .name("event-time").value(toRFC3339(now))
  62                         .name(DATA_CHANGED_NOTIFICATION_NAME).beginObject()
  63                             .name(DATA_CHANGED_EVENT_NAME).beginArray();
  64
  65                 final var serializer = new JSONDataTreeCandidateSerializer(schemaContext, jsonWriter);
  66                 for (var candidate : input) {
  67                     nonEmpty |= serializer.serialize(candidate, params);
  68                 }
  69
  70                 jsonWriter.endArray().endObject().endObject().endObject();
  71             }
  72
  73             return nonEmpty ? writer.toString() : null;
  74         }
  75     }
  76 }