opendaylight/commons/concepts/src/main/java/org/opendaylight/controller/concepts/transform/CompositeConditionalTransformer.java

   1 /*\r
   2  * Copyright (c) 2013 Cisco Systems, Inc. and others.  All rights reserved.\r
   3  *\r
   4  * This program and the accompanying materials are made available under the\r
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,\r
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html\r
   7  */\r
   8 \r
   9 package org.opendaylight.controller.concepts.transform;\r
  10 \r
  11 import java.util.ArrayList;\r
  12 import java.util.Collection;\r
  13 import java.util.Comparator;\r
  14 import java.util.Set;\r
  15 import java.util.TreeSet;\r
  16 \r
  17 /**\r
  18  * Composite transformer which aggregates multiple implementation and selects\r
  19  * the one which accepts the input.\r
  20  *\r
  21  *\r
  22  * @author Tony Tkacik\r
  23  *\r
  24  * @param <I>\r
  25  *            Input class for transformation\r
  26  * @param <P>\r
  27  *            Product of transformation\r
  28  */\r
  29 public class CompositeConditionalTransformer<I, P> implements\r
  30         SimpleConditionalTransformer<I, P>,\r
  31         AggregateTransformer<I,P> {\r
  32 \r
  33     private final Comparator<TransformerWithPriority<I, P>> comparator = new Comparator<TransformerWithPriority<I, P>>() {\r
  34 \r
  35         @Override\r
  36         public int compare(TransformerWithPriority<I, P> o1,\r
  37                 TransformerWithPriority<I, P> o2) {\r
  38             return Integer.valueOf(o1.priority).compareTo(Integer.valueOf(o2.priority));\r
  39         }\r
  40 \r
  41     };\r
  42     private final Set<TransformerWithPriority<I, P>> transformers;\r
  43 \r
  44     public CompositeConditionalTransformer() {\r
  45         // FIXME: Add Ordering\r
  46         transformers = new TreeSet<TransformerWithPriority<I, P>>(comparator);\r
  47     }\r
  48 \r
  49     @Override\r
  50     public boolean isAcceptable(I input) {\r
  51         for (SimpleConditionalTransformer<I, P> trans : transformers) {\r
  52             if (trans.isAcceptable(input)) {\r
  53                 return true;\r
  54             }\r
  55         }\r
  56         return false;\r
  57     }\r
  58 \r
  59     @Override\r
  60     public P transform(I input) {\r
  61         for (SimpleConditionalTransformer<I, P> trans : transformers) {\r
  62             if (trans.isAcceptable(input)) {\r
  63                 return trans.transform(input);\r
  64             }\r
  65         }\r
  66         throw new IllegalStateException(\r
  67                 "Transformer for provided input is not available.");\r
  68     }\r
  69 \r
  70     public void addTransformer(SimpleConditionalTransformer<I, P> transformer,\r
  71             int priority) throws IllegalStateException {\r
  72         if (transformer == null) {\r
  73             throw new IllegalArgumentException(\r
  74                     "transformer should not be null.");\r
  75         }\r
  76         TransformerWithPriority<I, P> withPriority = new TransformerWithPriority<I, P>(\r
  77                 transformer, priority);\r
  78         if (false == transformers.add(withPriority)) {\r
  79             throw new IllegalStateException("transformer " + transformer\r
  80                     + "already registered");\r
  81         }\r
  82     }\r
  83 \r
  84     public void removeTransformer(SimpleConditionalTransformer<I, P> transformer)\r
  85             throws IllegalArgumentException {\r
  86         if (transformer == null) {\r
  87             throw new IllegalArgumentException(\r
  88                     "transformer should not be null.");\r
  89         }\r
  90         if (false == transformers.remove(transformer)) {\r
  91             throw new IllegalStateException("transformer " + transformer\r
  92                     + "already registered");\r
  93         }\r
  94     }\r
  95 \r
  96     @Override\r
  97     public Collection<P> transformAll(Collection<? extends I> inputs) {\r
  98         Collection<P> ret = new ArrayList<P>();\r
  99         for (I i : inputs) {\r
 100             ret.add(transform(i));\r
 101         }\r
 102         return ret;\r
 103     }\r
 104 \r
 105     private static class TransformerWithPriority<I, P> implements\r
 106             SimpleConditionalTransformer<I, P> {\r
 107         final int priority;\r
 108         final SimpleConditionalTransformer<I, P> transformer;\r
 109 \r
 110         public TransformerWithPriority(\r
 111                 SimpleConditionalTransformer<I, P> transformer, int priority) {\r
 112             this.priority = priority;\r
 113             this.transformer = transformer;\r
 114         }\r
 115 \r
 116         @Override\r
 117         public int hashCode() {\r
 118             final int prime = 31;\r
 119             int result = 1;\r
 120             result = prime * result\r
 121                     + ((transformer == null) ? 0 : transformer.hashCode());\r
 122             return result;\r
 123         }\r
 124 \r
 125         @Override\r
 126         public boolean equals(Object obj) {\r
 127             if (this == obj)\r
 128                 return true;\r
 129             if (obj == null)\r
 130                 return false;\r
 131             if (getClass() != obj.getClass())\r
 132                 return false;\r
 133             TransformerWithPriority<?,?> other = (TransformerWithPriority<?,?>) obj;\r
 134             if (transformer == null) {\r
 135                 if (other.transformer != null)\r
 136                     return false;\r
 137             } else if (!transformer.equals(other.transformer))\r
 138                 return false;\r
 139             return true;\r
 140         }\r
 141 \r
 142         @Override\r
 143         public boolean isAcceptable(I input) {\r
 144             return transformer.isAcceptable(input);\r
 145         }\r
 146 \r
 147         @Override\r
 148         public P transform(I input) {\r
 149             return transformer.transform(input);\r
 150         }\r
 151 \r
 152 \r
 153 \r
 154 \r
 155 \r
 156     }\r
 157 }\r