bundles/org.simantics.objmap2/src/org/simantics/objmap/graph/rules/range/FieldAccessor.java

   1 /*******************************************************************************
   2  * Copyright (c) 2007, 2013 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.objmap.graph.rules.range;
  13
  14 import java.lang.reflect.Field;
  15
  16 import org.simantics.objmap.exceptions.MappingException;
  17 import org.slf4j.Logger;
  18 import org.slf4j.LoggerFactory;
  19
  20
  21 /**
  22  * Accesses the given field of the element.
  23  * @author Hannu Niemistö
  24  */
  25 public class FieldAccessor<Range,T> implements IRangeAccessor<Range,T> {
  26
  27     static final Logger LOGGER = LoggerFactory.getLogger(FieldAccessor.class);
  28
  29         Field field;
  30
  31         public FieldAccessor(Field field) {
  32                 this.field = field;
  33         }
  34
  35         @Override
  36         public T get(Range element) throws MappingException {
  37                 try {
  38                     @SuppressWarnings("unchecked")
  39                         T result = (T)field.get(element);
  40
  41                 if(LOGGER.isTraceEnabled())
  42                     LOGGER.trace("        FieldAccessor.get " +
  43                             field.getName() + " -> " + result
  44                     );
  45
  46                         return result;
  47                 } catch (IllegalArgumentException e) {
  48                         throw new MappingException(e);
  49                 } catch (IllegalAccessException e) {
  50                         throw new MappingException(e);
  51                 }
  52         }
  53
  54         @Override
  55         public boolean set(Range element, T value) throws MappingException {
  56                 try {
  57                         Object currentValue = field.get(element);
  58
  59             if(LOGGER.isTraceEnabled())
  60                 LOGGER.trace("        FieldAccessor.set " +
  61                         field.getName() + " " + currentValue +
  62                         " -> " + value
  63                 );
  64
  65                         if(value == null
  66                                 ? (currentValue == null || field.getType().isPrimitive())
  67                                 : value.equals(currentValue))
  68                                 return false;
  69                         field.set(element, value);
  70                         return true;
  71                 } catch (IllegalArgumentException e) {
  72                         throw new MappingException(e);
  73                 } catch (IllegalAccessException e) {
  74                         throw new MappingException(e);
  75                 }
  76         }
  77 }