opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/entityownership/selectionstrategy/EntityOwnerSelectionStrategyConfig.java

   1 /*
   2  * Copyright (c) 2015 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.cluster.datastore.entityownership.selectionstrategy;
  10
  11 import java.lang.reflect.InvocationTargetException;
  12 import java.util.HashMap;
  13 import java.util.Map;
  14 import org.slf4j.Logger;
  15 import org.slf4j.LoggerFactory;
  16
  17 /**
  18  * FIXME: this is simple registry service, except it also loads classes.
  19  */
  20 public final class EntityOwnerSelectionStrategyConfig {
  21     private static final Logger LOG = LoggerFactory.getLogger(EntityOwnerSelectionStrategyConfig.class);
  22     private final Map<String, StrategyInfo> entityTypeToStrategyInfo = new HashMap<>();
  23     private final Map<String, EntityOwnerSelectionStrategy> entityTypeToOwnerSelectionStrategy = new HashMap<>();
  24
  25     private EntityOwnerSelectionStrategyConfig() {
  26
  27     }
  28
  29     public boolean isStrategyConfigured(final String entityType) {
  30         return entityTypeToStrategyInfo.get(entityType) != null;
  31     }
  32
  33     public EntityOwnerSelectionStrategy createStrategy(final String entityType,
  34             final Map<String, Long> initialStatistics) {
  35         final EntityOwnerSelectionStrategy strategy;
  36         final EntityOwnerSelectionStrategy existingStrategy = entityTypeToOwnerSelectionStrategy.get(entityType);
  37         if (existingStrategy != null) {
  38             strategy = existingStrategy;
  39         } else {
  40             EntityOwnerSelectionStrategyConfig.StrategyInfo strategyInfo = entityTypeToStrategyInfo.get(entityType);
  41             if (strategyInfo == null) {
  42                 strategy = FirstCandidateSelectionStrategy.INSTANCE;
  43             } else {
  44                 strategy = strategyInfo.createStrategy(initialStatistics);
  45             }
  46             entityTypeToOwnerSelectionStrategy.put(entityType, strategy);
  47         }
  48         return strategy;
  49     }
  50
  51     /**
  52      * This class should not exist. It contains a single long, which is passed to the constructor (via reflection).
  53      * We are getting that information from a BundleContext. We are running in OSGi environment, hence this class
  54      * needs to be deployed in its own bundle, with its own configuration.
  55      * If this is used internally, it needs to be relocated into a separate package along with the implementation
  56      * using it.
  57      *
  58      * @deprecated FIXME: THIS IS CONFIGURATION FOR A CUSTOM-LOADED CLASS CONSTRUCTOR
  59      */
  60     @Deprecated
  61     public void clearStrategies() {
  62         entityTypeToOwnerSelectionStrategy.clear();
  63     }
  64
  65     private static final class StrategyInfo {
  66         private final Class<? extends EntityOwnerSelectionStrategy> strategyClass;
  67         private final long delay;
  68
  69         private StrategyInfo(final Class<? extends EntityOwnerSelectionStrategy> strategyClass, final long delay) {
  70             this.strategyClass = strategyClass;
  71             this.delay = delay;
  72         }
  73
  74         public EntityOwnerSelectionStrategy createStrategy(final Map<String, Long> initialStatistics) {
  75             try {
  76                 return strategyClass.getDeclaredConstructor(long.class, Map.class)
  77                         .newInstance(delay, initialStatistics);
  78             } catch (InstantiationException | IllegalAccessException | InvocationTargetException
  79                     | NoSuchMethodException e) {
  80                 LOG.warn("could not create custom strategy", e);
  81             }
  82             return FirstCandidateSelectionStrategy.INSTANCE;
  83         }
  84     }
  85
  86     public static Builder newBuilder() {
  87         return new Builder(new EntityOwnerSelectionStrategyConfig());
  88     }
  89
  90     public static final class Builder {
  91         private final EntityOwnerSelectionStrategyConfig config;
  92
  93         Builder(final EntityOwnerSelectionStrategyConfig config) {
  94             this.config = config;
  95         }
  96
  97         public Builder addStrategy(final String entityType,
  98                 final Class<? extends EntityOwnerSelectionStrategy> strategy, final long delay) {
  99             config.entityTypeToStrategyInfo.put(entityType, new StrategyInfo(strategy, delay));
 100             return this;
 101         }
 102
 103         public EntityOwnerSelectionStrategyConfig build() {
 104             return this.config;
 105         }
 106     }
 107 }