opendaylight/netconf/config-persister-impl/src/main/java/org/opendaylight/controller/netconf/persist/impl/PersisterImpl.java

   1 /*
   2  * Copyright (c) 2013 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
   9 package org.opendaylight.controller.netconf.persist.impl;
  10
  11 import com.google.common.annotations.VisibleForTesting;
  12 import com.google.common.base.Optional;
  13 import org.opendaylight.controller.config.persist.api.Persister;
  14 import org.opendaylight.controller.config.persist.api.storage.StorageAdapter;
  15 import org.osgi.framework.BundleContext;
  16
  17 import java.io.IOException;
  18
  19 /**
  20  * {@link Persister} implementation that delegates persisting functionality to
  21  * underlying {@link Persister} called Storage Adapter.
  22  *
  23  * Storage adapters are low level persisters that do the heavy lifting for this
  24  * class. Instances of storage adapters can be injected directly via constructor
  25  * or instantiated from a full name of its class provided in a properties file.
  26  *
  27  * Name of storage adapter class should be located under
  28  * {@link #STORAGE_ADAPTER_CLASS_PROP} key.
  29  */
  30 public final class PersisterImpl implements Persister {
  31
  32     public static final String STORAGE_ADAPTER_CLASS_PROP = "netconf.config.persister.storageAdapterClass";
  33     private final StorageAdapter storage;
  34
  35     public PersisterImpl(StorageAdapter storage) {
  36         this.storage = storage;
  37     }
  38
  39     public static Optional<PersisterImpl> createFromProperties(BundleContext bundleContext) {
  40         String storageAdapterClass = bundleContext.getProperty(STORAGE_ADAPTER_CLASS_PROP);
  41         StorageAdapter storage;
  42         if (storageAdapterClass == null || storageAdapterClass.equals("")) {
  43             return Optional.absent();
  44         }
  45
  46         try {
  47             storage = StorageAdapter.class.cast(resolveClass(storageAdapterClass, StorageAdapter.class).newInstance());
  48             storage.setProperties(bundleContext);
  49
  50         } catch (InstantiationException | IllegalAccessException | ClassNotFoundException e) {
  51             throw new IllegalArgumentException("Unable to instantiate storage adapter from " + storageAdapterClass, e);
  52         }
  53         return Optional.of(new PersisterImpl(storage));
  54     }
  55
  56     private static Class<?> resolveClass(String storageAdapterClass, Class<?> baseType) throws ClassNotFoundException {
  57         Class<?> clazz = Class.forName(storageAdapterClass);
  58
  59         if (!isImplemented(baseType, clazz))
  60             throw new IllegalArgumentException("Storage adapter " + clazz + " has to implement " + baseType);
  61         return clazz;
  62     }
  63
  64     private static boolean isImplemented(Class<?> expectedIface, Class<?> byClazz) {
  65         for (Class<?> iface : byClazz.getInterfaces()) {
  66             if (iface.equals(expectedIface))
  67                 return true;
  68         }
  69         return false;
  70     }
  71
  72     @Override
  73     public void persistConfig(ConfigSnapshotHolder holder) throws IOException {
  74         storage.persistConfig(holder);
  75     }
  76
  77     @Override
  78     public Optional<ConfigSnapshotHolder> loadLastConfig() throws IOException {
  79         return storage.loadLastConfig();
  80     }
  81
  82     @VisibleForTesting
  83     StorageAdapter getStorage() {
  84         return storage;
  85     }
  86
  87     @Override
  88     public void close() throws IOException {
  89         storage.close();
  90     }
  91
  92     @Override
  93     public String toString() {
  94         return "PersisterImpl [storage=" + storage + "]";
  95     }
  96 }