restconf/restconf-nb/src/main/java/org/opendaylight/restconf/nb/rfc8040/streams/listeners/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.nb.rfc8040.streams.listeners;
   9
  10 import static java.util.Objects.requireNonNull;
  11
  12 import com.google.gson.stream.JsonWriter;
  13 import java.io.IOException;
  14 import java.io.StringWriter;
  15 import java.time.Instant;
  16 import java.util.Collection;
  17 import javax.xml.xpath.XPathExpressionException;
  18 import org.eclipse.jdt.annotation.NonNull;
  19 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.controller.md.sal.remote.rev140114.$YangModuleInfoImpl;
  20 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.controller.md.sal.remote.rev140114.DataChangedNotification;
  21 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.controller.md.sal.remote.rev140114.data.changed.notification.DataChangeEvent;
  22 import org.opendaylight.yangtools.yang.data.codec.gson.JSONCodecFactorySupplier;
  23 import org.opendaylight.yangtools.yang.data.tree.api.DataTreeCandidate;
  24 import org.opendaylight.yangtools.yang.model.api.EffectiveModelContext;
  25
  26 public final class JSONDataTreeCandidateFormatter extends DataTreeCandidateFormatter {
  27     private static final @NonNull String NOTIFICATION_NAME = "ietf-restconf:notification";
  28
  29     private static final @NonNull String DATA_CHANGED_NOTIFICATION_NAME;
  30     private static final @NonNull String DATA_CHANGED_EVENT_NAME = DataChangeEvent.QNAME.getLocalName();
  31
  32     static {
  33         final var salRemoteName = $YangModuleInfoImpl.getInstance().getName().getLocalName();
  34         DATA_CHANGED_NOTIFICATION_NAME = salRemoteName + ":" + DataChangedNotification.QNAME.getLocalName();
  35     }
  36
  37     private final JSONCodecFactorySupplier codecSupplier;
  38
  39     private JSONDataTreeCandidateFormatter(final TextParameters textParams,
  40             final JSONCodecFactorySupplier codecSupplier) {
  41         super(textParams);
  42         this.codecSupplier = requireNonNull(codecSupplier);
  43     }
  44
  45     private JSONDataTreeCandidateFormatter(final TextParameters textParams, final String xpathFilter,
  46             final JSONCodecFactorySupplier codecSupplier) throws XPathExpressionException {
  47         super(textParams, xpathFilter);
  48         this.codecSupplier = requireNonNull(codecSupplier);
  49     }
  50
  51     public static DataTreeCandidateFormatterFactory createFactory(
  52             final JSONCodecFactorySupplier codecSupplier) {
  53         final var empty = new JSONDataTreeCandidateFormatter(TextParameters.EMPTY, codecSupplier);
  54         return new DataTreeCandidateFormatterFactory(empty) {
  55             @Override
  56             DataTreeCandidateFormatter newFormatter(final TextParameters textParams) {
  57                 return new JSONDataTreeCandidateFormatter(textParams, codecSupplier);
  58             }
  59
  60             @Override
  61             DataTreeCandidateFormatter getFormatter(final TextParameters textParams, final String xpathFilter)
  62                     throws XPathExpressionException {
  63                 return new JSONDataTreeCandidateFormatter(textParams, xpathFilter, codecSupplier);
  64             }
  65         };
  66     }
  67
  68     @Override
  69     String createText(final TextParameters params, final EffectiveModelContext schemaContext,
  70             final Collection<DataTreeCandidate> input, final Instant now) throws IOException {
  71         try (var writer = new StringWriter()) {
  72             boolean nonEmpty = false;
  73             try (var jsonWriter = new JsonWriter(writer)) {
  74                 jsonWriter.beginObject()
  75                     .name(NOTIFICATION_NAME).beginObject()
  76                         .name("event-time").value(toRFC3339(now))
  77                         .name(DATA_CHANGED_NOTIFICATION_NAME).beginObject()
  78                             .name(DATA_CHANGED_EVENT_NAME).beginArray();
  79
  80                 final var serializer = new JsonDataTreeCandidateSerializer(schemaContext, codecSupplier, jsonWriter);
  81                 for (var candidate : input) {
  82                     nonEmpty |= serializer.serialize(candidate, params);
  83                 }
  84
  85                 jsonWriter.endArray().endObject().endObject().endObject();
  86             }
  87
  88             return nonEmpty ? writer.toString() : null;
  89         }
  90     }
  91 }