opendaylight/md-sal/sal-dom-broker/src/main/java/org/opendaylight/controller/md/sal/dom/broker/impl/PingPongDataBroker.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.md.sal.dom.broker.impl;
   9
  10 import static java.util.Objects.requireNonNull;
  11
  12 import org.eclipse.jdt.annotation.NonNull;
  13 import org.opendaylight.controller.md.sal.common.api.data.TransactionChainListener;
  14 import org.opendaylight.controller.md.sal.dom.api.DOMDataBroker;
  15 import org.opendaylight.controller.md.sal.dom.api.DOMDataTreeChangeListener;
  16 import org.opendaylight.controller.md.sal.dom.api.DOMDataTreeChangeService;
  17 import org.opendaylight.controller.md.sal.dom.api.DOMDataTreeIdentifier;
  18 import org.opendaylight.controller.md.sal.dom.spi.ForwardingDOMDataBroker;
  19 import org.opendaylight.yangtools.concepts.ListenerRegistration;
  20
  21 /**
  22  * An implementation of a {@link DOMDataBroker}, which forwards most requests to a delegate.
  23  *
  24  * <p>
  25  * Its interpretation of the API contract is somewhat looser, specifically it does not
  26  * guarantee transaction ordering between transactions allocated directly from the broker
  27  * and its transaction chains.
  28  */
  29 public final class PingPongDataBroker extends ForwardingDOMDataBroker implements AutoCloseable,
  30         DOMDataTreeChangeService {
  31     private final DOMDataBroker delegate;
  32
  33     /**
  34      * Instantiate a new broker, backed by the the specified delegate
  35      * {@link DOMDataBroker}.
  36      *
  37      * @param delegate Backend broker, may not be null.
  38      */
  39     public PingPongDataBroker(final @NonNull DOMDataBroker delegate) {
  40         this.delegate = requireNonNull(delegate);
  41     }
  42
  43     @Override
  44     protected DOMDataBroker delegate() {
  45         return delegate;
  46     }
  47
  48     @Override
  49     public PingPongTransactionChain createTransactionChain(final TransactionChainListener listener) {
  50         return new PingPongTransactionChain(delegate, listener);
  51     }
  52
  53     @Override
  54     public void close() {
  55         // intentionally NOOP
  56     }
  57
  58     @Override
  59     public <L extends DOMDataTreeChangeListener> ListenerRegistration<L> registerDataTreeChangeListener(
  60             final DOMDataTreeIdentifier treeId, final L listener) {
  61         final DOMDataTreeChangeService treeService = (DOMDataTreeChangeService) delegate.getSupportedExtensions()
  62                 .get(DOMDataTreeChangeService.class);
  63         if (treeService != null) {
  64             return treeService.registerDataTreeChangeListener(treeId, listener);
  65         }
  66
  67         throw new UnsupportedOperationException("Delegate " + delegate + " does not support required functionality");
  68     }
  69
  70     @Override
  71     public String toString() {
  72         return "PingPongDataBroker backed by " + delegate;
  73     }
  74 }