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

   1 /*******************************************************************************
   2  * Copyright (c) 2007, 2010 Association for Decentralized Information Management
   3  * in Industry THTH ry.
   4  * All rights reserved. This program and the accompanying materials
   5  * are made available under the terms of the Eclipse Public License v1.0
   6  * which accompanies this distribution, and is available at
   7  * http://www.eclipse.org/legal/epl-v10.html
   8  *
   9  * Contributors:
  10  *     VTT Technical Research Centre of Finland - initial API and implementation
  11  *******************************************************************************/
  12 package org.simantics.g2d.canvas.impl;
  13
  14 import java.lang.annotation.ElementType;
  15 import java.lang.annotation.Retention;
  16 import java.lang.annotation.RetentionPolicy;
  17 import java.lang.annotation.Target;
  18 import java.lang.reflect.Field;
  19 import java.util.ArrayList;
  20 import java.util.Collection;
  21 import java.util.List;
  22
  23 import org.simantics.g2d.canvas.ICanvasParticipant;
  24 import org.simantics.g2d.diagram.handler.DiagramHandler;
  25
  26 /**
  27  * @author Toni Kalajainen
  28  */
  29 public class DependencyReflection {
  30
  31         private final static ReferenceDefinition[] EMPTY = new ReferenceDefinition[0];
  32
  33         @Retention(RetentionPolicy.RUNTIME)
  34         @Target(ElementType.FIELD)
  35         public static @interface Dependency {}
  36         @Retention(RetentionPolicy.RUNTIME)
  37         @Target(ElementType.FIELD)
  38         public static @interface Reference {}
  39
  40         /**
  41          * Scans an object with reflection for all dependencies
  42          * <p>
  43          * Example:
  44          *
  45          * @Dependency
  46          * ViewportInteractor vi;
  47          *
  48          * @param obj object to scan
  49          * @return an array of painters and their priorities
  50          */
  51         public static ReferenceDefinition[] getDependencies(final Object obj, ReferenceType type)
  52         {
  53                 List<ReferenceDefinition> result = new ArrayList<ReferenceDefinition>();
  54                 Class<?> clazz = obj.getClass();
  55                 _addDependencies(clazz, result, type);
  56                 //if (result==null) return EMPTY;
  57                 return result.toArray(EMPTY);
  58         }
  59
  60     private static void _addDependencies(Class<?> clazz, Collection<ReferenceDefinition> result, ReferenceType type)
  61         {
  62                 for (final Field f : clazz.getDeclaredFields()) {
  63                         Class<?> c = f.getType();
  64                         Dependency dep = (Dependency) f.getAnnotation(Dependency.class);
  65                         Reference ref = (Reference) f.getAnnotation(Reference.class);
  66                         if (dep==null && ref==null) continue;
  67                         ReferenceType referenceType = null;
  68                         if ( ICanvasParticipant.class.isAssignableFrom( c ) )
  69                                 referenceType = ReferenceType.CanvasParticipant;
  70                         else if ( DiagramHandler.class.isAssignableFrom( c ) )
  71                                 referenceType = ReferenceType.DiagramHandler;
  72                         else assert(false);
  73                         if (referenceType!=type) continue;
  74
  75                         assert(!(dep!=null && ref!=null));
  76                         ReferenceDefinition rd = new ReferenceDefinition();
  77                         rd.dependency = dep!=null;
  78                         rd.field = f;
  79                         rd.requirement = c;
  80                         rd.referenceType = referenceType;
  81
  82                         f.setAccessible(true);
  83                         result.add(rd);
  84                 }
  85                 Class<?> superClass = clazz.getSuperclass();
  86                 if (superClass!=null)
  87                         _addDependencies(superClass, result, type);
  88         }
  89
  90         public final static class ReferenceDefinition {
  91                 public Class<?> requirement;
  92                 public Field field;
  93                 public boolean dependency;
  94                 public ReferenceType referenceType;
  95         }
  96
  97         public static enum ReferenceType {
  98                 CanvasParticipant, DiagramHandler
  99         }
 100
 101 }