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