opendaylight/netconf/netconf-util/src/main/java/org/opendaylight/controller/netconf/util/handler/NetconfEXIToMessageDecoder.java

   1 /*
   2  * Copyright (c) 2014 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.controller.netconf.util.handler;
   9
  10 import io.netty.buffer.ByteBuf;
  11 import io.netty.buffer.ByteBufInputStream;
  12 import io.netty.channel.ChannelHandlerContext;
  13 import io.netty.handler.codec.ByteToMessageDecoder;
  14
  15 import java.io.InputStream;
  16 import java.util.List;
  17
  18 import javax.xml.transform.dom.DOMResult;
  19 import javax.xml.transform.sax.SAXTransformerFactory;
  20 import javax.xml.transform.sax.TransformerHandler;
  21
  22 import org.opendaylight.controller.netconf.api.NetconfMessage;
  23 import org.openexi.sax.EXIReader;
  24 import org.w3c.dom.Document;
  25 import org.xml.sax.InputSource;
  26
  27 import com.google.common.base.Preconditions;
  28
  29 public final class NetconfEXIToMessageDecoder extends ByteToMessageDecoder {
  30     private static final SAXTransformerFactory saxTransformerFactory = (SAXTransformerFactory)SAXTransformerFactory.newInstance();
  31
  32     // FIXME: is this needed?
  33     //    private static final SAXParserFactory saxParserFactory;
  34     //    static {
  35     //        saxParserFactory = SAXParserFactory.newInstance();
  36     //        saxParserFactory.setNamespaceAware(true);
  37     //    }
  38
  39     private final NetconfEXICodec codec;
  40
  41     public NetconfEXIToMessageDecoder(final NetconfEXICodec codec) {
  42         this.codec = Preconditions.checkNotNull(codec);
  43     }
  44
  45     @Override
  46     protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
  47         /*
  48          * Note that we could loop here and process all the messages, but we can't do that.
  49          * The reason is <stop-exi> operation, which has the contract of immediately stopping
  50          * the use of EXI, which means the next message needs to be decoded not by us, but rather
  51          * by the XML decoder.
  52          */
  53         final DOMResult result = new DOMResult();
  54         final EXIReader r = codec.getReader();
  55
  56         final TransformerHandler transformerHandler = saxTransformerFactory.newTransformerHandler();
  57         transformerHandler.setResult(result);
  58         r.setContentHandler(transformerHandler);
  59
  60         try (final InputStream is = new ByteBufInputStream(in)) {
  61             r.parse(new InputSource(is));
  62         }
  63         out.add(new NetconfMessage((Document) result.getNode()));
  64     }
  65 }