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