yang/yang-data-codec-gson/src/test/java/org/opendaylight/yangtools/yang/data/codec/gson/StreamToNormalizedNodeTest.java

   1 /*
   2  * Copyright (c) 2016 Cisco Systems, Inc. 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.yangtools.yang.data.codec.gson;
   9
  10 import static org.opendaylight.yangtools.yang.data.codec.gson.TestUtils.loadTextFile;
  11
  12 import com.google.gson.stream.JsonReader;
  13 import java.io.File;
  14 import java.io.IOException;
  15 import java.io.StringReader;
  16 import java.io.StringWriter;
  17 import java.net.URISyntaxException;
  18 import org.junit.AfterClass;
  19 import org.junit.BeforeClass;
  20 import org.junit.Test;
  21 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.PathArgument;
  22 import org.opendaylight.yangtools.yang.data.api.schema.DataContainerChild;
  23 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  24 import org.opendaylight.yangtools.yang.data.api.schema.stream.LoggingNormalizedNodeStreamWriter;
  25 import org.opendaylight.yangtools.yang.data.api.schema.stream.NormalizedNodeStreamWriter;
  26 import org.opendaylight.yangtools.yang.data.api.schema.stream.NormalizedNodeWriter;
  27 import org.opendaylight.yangtools.yang.data.impl.schema.ImmutableNormalizedNodeStreamWriter;
  28 import org.opendaylight.yangtools.yang.data.impl.schema.NormalizedNodeResult;
  29 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
  30 import org.opendaylight.yangtools.yang.model.api.SchemaPath;
  31 import org.opendaylight.yangtools.yang.test.util.YangParserTestUtils;
  32 import org.slf4j.Logger;
  33 import org.slf4j.LoggerFactory;
  34
  35 public class StreamToNormalizedNodeTest {
  36     private static final Logger LOG = LoggerFactory.getLogger(StreamToNormalizedNodeTest.class);
  37     private static SchemaContext schemaContext;
  38     private static String streamAsString;
  39
  40     @BeforeClass
  41     public static void initialization() throws IOException, URISyntaxException {
  42         schemaContext = YangParserTestUtils.parseYangResourceDirectory("/complexjson/yang");
  43         streamAsString = loadTextFile(new File(StreamToNormalizedNodeTest.class.getResource(
  44                 "/complexjson/complex-json.json").toURI()));
  45     }
  46
  47     @AfterClass
  48     public static void cleanup() {
  49         schemaContext = null;
  50         streamAsString = null;
  51     }
  52
  53     /**
  54      * Demonstrates how to log events produced by a {@link JsonReader}.
  55      */
  56     @Test
  57     public void ownStreamWriterImplementationDemonstration() throws IOException {
  58         // GSON's JsonReader reading from the loaded string (our event source)
  59         final JsonReader reader = new JsonReader(new StringReader(streamAsString));
  60
  61         // StreamWriter which outputs SLF4J events
  62         final LoggingNormalizedNodeStreamWriter logWriter = new LoggingNormalizedNodeStreamWriter();
  63
  64         // JSON -> StreamWriter parser
  65         try (JsonParserStream jsonHandler = JsonParserStream.create(logWriter,
  66             JSONCodecFactorySupplier.DRAFT_LHOTKA_NETMOD_YANG_JSON_02.getShared(schemaContext))) {
  67             // Process multiple readers, flush()/close() as needed
  68             jsonHandler.parse(reader);
  69         }
  70     }
  71
  72     /**
  73      * Demonstrates how to create an immutable NormalizedNode tree from a {@link JsonReader} and
  74      * then writes the data back into string representation.
  75      */
  76     @Test
  77     public void immutableNormalizedNodeStreamWriterDemonstration() throws IOException {
  78         /*
  79          * This is the parsing part
  80          */
  81         // This is where we will output the nodes
  82         NormalizedNodeResult result = new NormalizedNodeResult();
  83
  84         // StreamWriter which attaches NormalizedNode under parent
  85         final NormalizedNodeStreamWriter streamWriter = ImmutableNormalizedNodeStreamWriter.from(result);
  86
  87         // JSON -> StreamWriter parser
  88         try (JsonParserStream handler = JsonParserStream.create(streamWriter,
  89             JSONCodecFactorySupplier.DRAFT_LHOTKA_NETMOD_YANG_JSON_02.getShared(schemaContext))) {
  90             handler.parse(new JsonReader(new StringReader(streamAsString)));
  91         }
  92
  93         // Finally build the node
  94         final NormalizedNode<?, ?> parsedData = result.getResult();
  95         LOG.debug("Parsed NormalizedNodes: {}", parsedData);
  96
  97         /*
  98          * This is the serialization part.
  99          */
 100         // We want to write the first child out
 101         final DataContainerChild<? extends PathArgument, ?> firstChild =
 102                 (DataContainerChild<? extends PathArgument, ?>) parsedData;
 103         LOG.debug("Serializing first child: {}", firstChild);
 104
 105         // String holder
 106         final StringWriter writer = new StringWriter();
 107
 108         // StreamWriter which outputs JSON strings
 109         // StreamWriter which outputs JSON strings
 110         final NormalizedNodeStreamWriter jsonStream = JSONNormalizedNodeStreamWriter.createExclusiveWriter(
 111             JSONCodecFactorySupplier.DRAFT_LHOTKA_NETMOD_YANG_JSON_02.getShared(schemaContext), SchemaPath.ROOT, null,
 112             JsonWriterFactory.createJsonWriter(writer, 2));
 113
 114         // NormalizedNode -> StreamWriter
 115         final NormalizedNodeWriter nodeWriter = NormalizedNodeWriter.forStreamWriter(jsonStream);
 116
 117         // Write multiple NormalizedNodes fluently, flush()/close() as needed
 118         nodeWriter.write(firstChild).close();
 119
 120         // Just to put it somewhere
 121         LOG.debug("Serialized JSON: {}", writer.toString());
 122     }
 123 }