opendaylight/md-sal/sal-distributed-eos/src/main/java/org/opendaylight/controller/cluster/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 package org.opendaylight.controller.cluster.entityownership.selectionstrategy;
   9
  10 import java.lang.reflect.InvocationTargetException;
  11 import java.util.HashMap;
  12 import java.util.Map;
  13 import org.slf4j.Logger;
  14 import org.slf4j.LoggerFactory;
  15
  16 /**
  17  * FIXME: this is simple registry service, except it also loads classes.
  18  */
  19 public final class EntityOwnerSelectionStrategyConfig {
  20     private static final Logger LOG = LoggerFactory.getLogger(EntityOwnerSelectionStrategyConfig.class);
  21     private final Map<String, StrategyInfo> entityTypeToStrategyInfo = new HashMap<>();
  22     private final Map<String, EntityOwnerSelectionStrategy> entityTypeToOwnerSelectionStrategy = new HashMap<>();
  23
  24     private EntityOwnerSelectionStrategyConfig() {
  25
  26     }
  27
  28     public boolean isStrategyConfigured(final String entityType) {
  29         return entityTypeToStrategyInfo.get(entityType) != null;
  30     }
  31
  32     public EntityOwnerSelectionStrategy createStrategy(final String entityType,
  33             final 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      * This class should not exist. It contains a single long, which is passed to the constructor (via reflection).
  52      * We are getting that information from a BundleContext. We are running in OSGi environment, hence this class
  53      * needs to be deployed in its own bundle, with its own configuration.
  54      * If this is used internally, it needs to be relocated into a separate package along with the implementation
  55      * using it.
  56      *
  57      * @deprecated FIXME: THIS IS CONFIGURATION FOR A CUSTOM-LOADED CLASS CONSTRUCTOR
  58      */
  59     @Deprecated
  60     public void clearStrategies() {
  61         entityTypeToOwnerSelectionStrategy.clear();
  62     }
  63
  64     private static final class StrategyInfo {
  65         private final Class<? extends EntityOwnerSelectionStrategy> strategyClass;
  66         private final long delay;
  67
  68         private StrategyInfo(final Class<? extends EntityOwnerSelectionStrategy> strategyClass, final long delay) {
  69             this.strategyClass = strategyClass;
  70             this.delay = delay;
  71         }
  72
  73         public EntityOwnerSelectionStrategy createStrategy(final Map<String, Long> initialStatistics) {
  74             try {
  75                 return strategyClass.getDeclaredConstructor(long.class, Map.class)
  76                         .newInstance(delay, initialStatistics);
  77             } catch (InstantiationException | IllegalAccessException | InvocationTargetException
  78                     | NoSuchMethodException e) {
  79                 LOG.warn("could not create custom strategy", e);
  80             }
  81             return FirstCandidateSelectionStrategy.INSTANCE;
  82         }
  83     }
  84
  85     public static Builder newBuilder() {
  86         return new Builder(new EntityOwnerSelectionStrategyConfig());
  87     }
  88
  89     public static final class Builder {
  90         private final EntityOwnerSelectionStrategyConfig config;
  91
  92         Builder(final EntityOwnerSelectionStrategyConfig config) {
  93             this.config = config;
  94         }
  95
  96         public Builder addStrategy(final String entityType,
  97                 final Class<? extends EntityOwnerSelectionStrategy> strategy, final long delay) {
  98             config.entityTypeToStrategyInfo.put(entityType, new StrategyInfo(strategy, delay));
  99             return this;
 100         }
 101
 102         public EntityOwnerSelectionStrategyConfig build() {
 103             return this.config;
 104         }
 105     }
 106 }