bundles/org.simantics.databoard/src/org/simantics/databoard/binding/reflection/UnionClassBinding.java

   1 /*******************************************************************************\r
   2  *  Copyright (c) 2010 Association for Decentralized Information Management in\r
   3  *  Industry THTH ry.\r
   4  *  All rights reserved. This program and the accompanying materials\r
   5  *  are made available under the terms of the Eclipse Public License v1.0\r
   6  *  which accompanies this distribution, and is available at\r
   7  *  http://www.eclipse.org/legal/epl-v10.html\r
   8  *\r
   9  *  Contributors:\r
  10  *      VTT Technical Research Centre of Finland - initial API and implementation\r
  11  *******************************************************************************/\r
  12 package org.simantics.databoard.binding.reflection;
  13
  14 import org.simantics.databoard.Bindings;\r
  15 import org.simantics.databoard.adapter.AdaptException;\r
  16 import org.simantics.databoard.binding.Binding;\r
  17 import org.simantics.databoard.binding.UnionBinding;\r
  18 import org.simantics.databoard.binding.error.BindingConstructionException;\r
  19 import org.simantics.databoard.binding.error.BindingException;\r
  20 import org.simantics.databoard.serialization.Serializer;\r
  21 import org.simantics.databoard.serialization.SpecializedSerializerProvider;\r
  22 import org.simantics.databoard.type.UnionType;\r
  23
  24 /**\r
  25  * Bindings an abstract class with @Union annotation to a DataBoard's UnionType.
  26  * \r
  27  * Example of usage:\r
  28  *  @Union({Rectangle.class, Circle.class, Triangle.class}) class Shape {}\r
  29  *      \r
  30  *  class Rectangle extends Shape { public int width, height; }\r
  31  *  class Circle extends Shape { public int radius; }           \r
  32  *  class Triangle extends Shape { public int sideLength; }             \r
  33  *
  34  * @author Toni Kalajainen
  35  */
  36 class UnionClassBinding extends UnionBinding implements SpecializedSerializerProvider {
  37
  38         Class<?>[] componentClasses;\r
  39         Serializer specializedSerializer;\r
  40
  41         public UnionClassBinding(UnionType type)
  42         throws BindingConstructionException {
  43                 this.type = type;\r
  44         }\r
  45         \r
  46         @Override
  47         public Object create(int tag, Object value) {
  48                 return value;
  49         }
  50
  51     @Override
  52     public void setValue(Object union, int tag, Object value)
  53         throws BindingException {\r
  54         if (tag != getTag(union)) throw new BindingException("Cannot change the class of an instance");\r
  55         Binding cb = getComponentBinding(tag);\r
  56         cb.readFrom(cb, value, union);
  57     }\r
  58
  59         @Override
  60         public int getTag(Object obj) throws BindingException {
  61                 for (int i=0; i<componentClasses.length; i++)
  62                         if (componentClasses[i].isInstance(obj)) return i;\r
  63                 throw new BindingException(obj.getClass().getSimpleName()+" is not a known component class");\r
  64         }
  65         @Override
  66         public Object getValue(Object obj) {
  67                 return obj;
  68         }
  69         @Override
  70         public boolean isInstance(Object obj) {
  71                 for (Class<?> c : componentClasses)
  72                         if (c.isInstance(obj)) return true;
  73                 return false;
  74         }\r
  75 \r
  76     @Override\r
  77     public Serializer getSpecializedSerializer() {\r
  78         return specializedSerializer;\r
  79     }
  80 \r
  81 \r
  82         transient Boolean isImmutable;\r
  83         \r
  84         @Override\r
  85         public synchronized boolean isImmutable() {\r
  86                 if ( isImmutable == null ) {\r
  87                         boolean b = true;\r
  88                         for ( Binding cb : getComponentBindings() ) {\r
  89                                 b &= cb.isImmutable();\r
  90                                 if (!b) break;\r
  91                         }\r
  92                         isImmutable = b;\r
  93                 }\r
  94                 return isImmutable;\r
  95         }\r
  96 \r
  97         @Override\r
  98     public Object readFromTry(Binding srcBinding, Object src, Object dst) throws BindingException\r
  99     {\r
 100                 UnionBinding sb = (UnionBinding) srcBinding;\r
 101                 int st = sb.getTag(src);\r
 102                 int dt = getTag(dst);\r
 103                 Binding scb = sb.getComponentBinding(st);\r
 104                 Object sv = sb.getValue(src);\r
 105                 \r
 106                 \r
 107                 if (st==dt) {\r
 108                         // Same Tag\r
 109                         Object dv = getValue(dst);\r
 110                         Binding dcb = getComponentBinding(dt);\r
 111                         dcb.readFrom(scb, sv, dv);\r
 112                         return dv;\r
 113                 } else {\r
 114                         // Different Tag -> return cloned or (same, if immutable) value\r
 115                         try {\r
 116                                 Binding dcb = getComponentBinding(st);\r
 117                                 return Bindings.adapt(src, scb, dcb);\r
 118                         } catch(AdaptException e) {\r
 119                                 throw new BindingException(e);\r
 120                         }\r
 121                 }\r
 122                 \r
 123         }       \r
 124         \r
 125         /**\r
 126          * Returns true if the tag of this union type can be modified\r
 127          *  \r
 128          * @return\r
 129          */\r
 130         public boolean isTagMutable() {\r
 131                 return true;\r
 132         }\r
 133  \r
 134         @Override\r
 135         protected boolean baseEquals(Object obj) {\r
 136                 if (!super.baseEquals(obj)) return false;       \r
 137 \r
 138                 UnionClassBinding o = (UnionClassBinding)obj;\r
 139                 if (isImmutable != o.isImmutable) return false;\r
 140                 if (specializedSerializer != o.specializedSerializer) return false;\r
 141                 if (componentClasses.length != o.componentClasses.length) return false;\r
 142                 \r
 143                 for (int i = 0; i < componentClasses.length; i++) {\r
 144                         if (!componentClasses[i].equals(o.componentClasses[i]))\r
 145                                 return false;\r
 146                 }\r
 147                 \r
 148                 return true;\r
 149         }\r
 150         \r
 151         @Override\r
 152         public int baseHashCode() {\r
 153                 int code = super.baseHashCode();\r
 154                 for (int i = 0; i < componentClasses.length; i++)\r
 155                         code = 23 * code + componentClasses.hashCode();\r
 156                 \r
 157                 return code;\r
 158         }
 159 }\r