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(String entityType, Map<String, Long> initialStatistics){
  34         final EntityOwnerSelectionStrategy strategy;
  35         final EntityOwnerSelectionStrategy existingStrategy = entityTypeToOwnerSelectionStrategy.get(entityType);
  36         if(existingStrategy != null){
  37             strategy = existingStrategy;
  38         } else {
  39             EntityOwnerSelectionStrategyConfig.StrategyInfo strategyInfo = entityTypeToStrategyInfo.get(entityType);
  40             if(strategyInfo == null){
  41                 strategy = FirstCandidateSelectionStrategy.INSTANCE;
  42             } else {
  43                 strategy = strategyInfo.createStrategy(initialStatistics);
  44             }
  45             entityTypeToOwnerSelectionStrategy.put(entityType, strategy);
  46         }
  47         return strategy;
  48     }
  49
  50     /**
  51      * @deprecated FIXME: THIS IS CONFIGURATION FOR A CUSTOM-LOADED CLASS CONSTRUCTOR
  52      *
  53      * This class should not exist. It contains a single long, which is passed to the constructor (via reflection).
  54      * We are getting that information from a BundleContext. We are running in OSGi environment, hence this class
  55      * needs to be deployed in its own bundle, with its own configuration.
  56      *
  57      * If this is used internally, it needs to be relocated into a separate package along with the implementation
  58      * using it.
  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(Map<String, Long> initialStatistics){
  75             try {
  76                 return strategyClass.getDeclaredConstructor(long.class, Map.class).newInstance(delay, initialStatistics);
  77             } catch (InstantiationException | IllegalAccessException | InvocationTargetException | NoSuchMethodException e) {
  78                 LOG.warn("could not create custom strategy", e);
  79             }
  80             return FirstCandidateSelectionStrategy.INSTANCE;
  81         }
  82     }
  83
  84     public static Builder newBuilder() {
  85         return new Builder(new EntityOwnerSelectionStrategyConfig());
  86     }
  87
  88     public static class Builder {
  89         private final EntityOwnerSelectionStrategyConfig config;
  90
  91         private Builder(final EntityOwnerSelectionStrategyConfig config){
  92             this.config = config;
  93         }
  94
  95         public Builder addStrategy(final String entityType, final Class<? extends EntityOwnerSelectionStrategy> strategy, final long delay){
  96             config.entityTypeToStrategyInfo.put(entityType, new StrategyInfo(strategy, delay));
  97             return this;
  98         }
  99
 100         public EntityOwnerSelectionStrategyConfig build(){
 101             return this.config;
 102         }
 103     }
 104 }