bundles/org.simantics.g2d/src/org/simantics/g2d/canvas/impl/DependencyReflection.java

   1 /*******************************************************************************\r
   2  * Copyright (c) 2007, 2010 Association for Decentralized Information Management\r
   3  * in 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.g2d.canvas.impl;\r
  13 \r
  14 import java.lang.annotation.ElementType;\r
  15 import java.lang.annotation.Retention;\r
  16 import java.lang.annotation.RetentionPolicy;\r
  17 import java.lang.annotation.Target;\r
  18 import java.lang.reflect.Field;\r
  19 import java.util.ArrayList;\r
  20 import java.util.Collection;\r
  21 import java.util.List;\r
  22 \r
  23 import org.simantics.g2d.canvas.ICanvasParticipant;\r
  24 import org.simantics.g2d.diagram.handler.DiagramHandler;\r
  25 \r
  26 /**\r
  27  * @author Toni Kalajainen\r
  28  */\r
  29 public class DependencyReflection {\r
  30 \r
  31         private final static ReferenceDefinition[] EMPTY = new ReferenceDefinition[0]; \r
  32         \r
  33         @Retention(RetentionPolicy.RUNTIME)\r
  34         @Target(ElementType.FIELD)\r
  35         public static @interface Dependency {}\r
  36         @Retention(RetentionPolicy.RUNTIME)\r
  37         @Target(ElementType.FIELD)\r
  38         public static @interface Reference {}\r
  39         \r
  40         /**\r
  41          * Scans an object with reflection for all dependencies \r
  42          * <p>\r
  43          * Example:\r
  44          * \r
  45          * @Dependency\r
  46          * ViewportInteractor vi;\r
  47          * \r
  48          * @param obj object to scan\r
  49          * @return an array of painters and their priorities\r
  50          */\r
  51         public static ReferenceDefinition[] getDependencies(final Object obj, ReferenceType type)\r
  52         {\r
  53                 List<ReferenceDefinition> result = new ArrayList<ReferenceDefinition>();\r
  54                 Class<?> clazz = obj.getClass();\r
  55                 _addDependencies(clazz, result, type);\r
  56                 //if (result==null) return EMPTY;\r
  57                 return result.toArray(EMPTY);\r
  58         }\r
  59 \r
  60     private static void _addDependencies(Class<?> clazz, Collection<ReferenceDefinition> result, ReferenceType type)\r
  61         {\r
  62                 for (final Field f : clazz.getDeclaredFields()) {\r
  63                         Class<?> c = f.getType();\r
  64                         Dependency dep = (Dependency) f.getAnnotation(Dependency.class);\r
  65                         Reference ref = (Reference) f.getAnnotation(Reference.class);\r
  66                         if (dep==null && ref==null) continue;\r
  67                         ReferenceType referenceType = null;                     \r
  68                         if ( ICanvasParticipant.class.isAssignableFrom( c ) )\r
  69                                 referenceType = ReferenceType.CanvasParticipant;\r
  70                         else if ( DiagramHandler.class.isAssignableFrom( c ) )\r
  71                                 referenceType = ReferenceType.DiagramHandler;\r
  72                         else assert(false);\r
  73                         if (referenceType!=type) continue;\r
  74                         \r
  75                         assert(!(dep!=null && ref!=null));\r
  76                         ReferenceDefinition rd = new ReferenceDefinition();\r
  77                         rd.dependency = dep!=null;\r
  78                         rd.field = f;\r
  79                         rd.requirement = c;\r
  80                         rd.referenceType = referenceType;\r
  81                         \r
  82                         f.setAccessible(true);\r
  83                         result.add(rd);\r
  84                 }\r
  85                 Class<?> superClass = clazz.getSuperclass();\r
  86                 if (superClass!=null)\r
  87                         _addDependencies(superClass, result, type);\r
  88         }\r
  89         \r
  90         public final static class ReferenceDefinition {\r
  91                 public Class<?> requirement;\r
  92                 public Field field;\r
  93                 public boolean dependency;\r
  94                 public ReferenceType referenceType; \r
  95         }       \r
  96         \r
  97         public static enum ReferenceType {\r
  98                 CanvasParticipant, DiagramHandler\r
  99         }\r
 100         \r
 101 }\r