bundles/org.simantics.databoard/src/org/simantics/databoard/binding/util/DefaultValue.java

   1 /*******************************************************************************
   2  *  Copyright (c) 2010 Association for Decentralized Information Management in
   3  *  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.databoard.binding.util;
  13
  14 import java.util.Map;
  15 import java.util.WeakHashMap;
  16
  17 import org.simantics.databoard.Bindings;
  18 import org.simantics.databoard.binding.ArrayBinding;
  19 import org.simantics.databoard.binding.Binding;
  20 import org.simantics.databoard.binding.Binding.Visitor;
  21 import org.simantics.databoard.binding.BooleanBinding;
  22 import org.simantics.databoard.binding.ByteBinding;
  23 import org.simantics.databoard.binding.DoubleBinding;
  24 import org.simantics.databoard.binding.FloatBinding;
  25 import org.simantics.databoard.binding.IntegerBinding;
  26 import org.simantics.databoard.binding.LongBinding;
  27 import org.simantics.databoard.binding.MapBinding;
  28 import org.simantics.databoard.binding.OptionalBinding;
  29 import org.simantics.databoard.binding.RecordBinding;
  30 import org.simantics.databoard.binding.StringBinding;
  31 import org.simantics.databoard.binding.UnionBinding;
  32 import org.simantics.databoard.binding.VariantBinding;
  33 import org.simantics.databoard.binding.error.BindingException;
  34 import org.simantics.databoard.binding.error.RuntimeBindingException;
  35 import org.simantics.databoard.type.ArrayType;
  36 import org.simantics.databoard.type.ByteType;
  37 import org.simantics.databoard.type.DoubleType;
  38 import org.simantics.databoard.type.FloatType;
  39 import org.simantics.databoard.type.IntegerType;
  40 import org.simantics.databoard.type.LongType;
  41 import org.simantics.databoard.type.StringType;
  42 import org.simantics.databoard.util.Range;
  43
  44 /**
  45  * Visitor that creates a default instance of a DataType.
  46  * This visitor may throw RuntimeBindingException.
  47  *
  48  * Type                     Value
  49  * ------------------------------------------------------
  50  * Boolean                  false
  51  * Byte, Integer, Long      0 or min limit
  52  * Float, Double            0.0 or min limit
  53  * String                   ""
  54  * Optional                 *novalue*
  55  * Union                    tag 0
  56  * Record                   each field with default value
  57  * Array                    min range number of elements
  58  * Map                      no entries
  59  * Variant                  {} : void
  60  *
  61  *
  62  * TODO Create String according to the pattern
  63  * @author Toni Kalajainen <toni.kalajainen@vtt.fi>
  64  */
  65 public class DefaultValue implements Visitor<Object> {
  66
  67         /** Map of default values already created. Used to link back to recursive records */
  68         Map<Binding, Object> map = new WeakHashMap<Binding, Object>(1);
  69
  70         @Override
  71         public Object visit(ArrayBinding b) {
  72                 Object result = null;
  73
  74                 ArrayType at = b.type();
  75                 Range r = at.getLength();
  76                 int min = (r!=null) ? r.getLower().getValue().intValue() : 0;
  77
  78                 if (min>0) {
  79                         Binding componentBinding = b.getComponentBinding();
  80                         Object[] array = new Object[min];
  81                         for (int i=0; i<min; i++) {
  82                                 array[i] = componentBinding.accept(this);
  83                         }
  84                         result = b.createUnchecked(array);
  85                 } else {
  86                         result = b.createUnchecked();
  87                 }
  88                 return result;
  89         }
  90
  91         @Override
  92         public Object visit(BooleanBinding b) {
  93                 Object result = b.createUnchecked(Boolean.FALSE);
  94                 return result;
  95         }
  96
  97         @Override
  98         public Object visit(DoubleBinding b) {
  99                 DoubleType type = b.type();
 100                 Range range = type.getRange();
 101                 Number lowValue = range==null ? null : range.getLower().getValue();
 102                 return b.createUnchecked( lowValue == null ? 0 : lowValue.doubleValue() );
 103         }
 104
 105         @Override
 106         public Object visit(FloatBinding b) {
 107                 FloatType type = b.type();
 108                 Range range = type.getRange();
 109                 Number lowValue = range==null ? null : range.getLower().getValue();
 110                 return b.createUnchecked( lowValue == null ? 0 : lowValue.floatValue() );
 111         }
 112
 113         @Override
 114         public Object visit(IntegerBinding b) {
 115                 IntegerType type = b.type();
 116                 Range range = type.getRange();
 117                 Number lowValue = range==null ? null : range.getLower().getValue();
 118                 return b.createUnchecked( lowValue == null ? 0 : lowValue.intValue() );
 119         }
 120
 121         @Override
 122         public Object visit(ByteBinding b) {
 123                 ByteType type = b.type();
 124                 Range range = type.getRange();
 125                 Number lowValue = range==null ? null : range.getLower().getValue();
 126                 return b.createUnchecked( lowValue == null ? 0 : lowValue.intValue() );
 127         }
 128
 129         @Override
 130         public Object visit(LongBinding b) {
 131                 LongType type = b.type();
 132                 Range range = type.getRange();
 133                 Number lowValue = range==null ? null : range.getLower().getValue();
 134                 return b.createUnchecked( lowValue == null ? 0 : lowValue.longValue() );
 135         }
 136
 137         @Override
 138         public Object visit(OptionalBinding b) {
 139                 return b.createNoValueUnchecked();
 140         }
 141
 142         @Override
 143         public Object visit(RecordBinding b) {
 144                 try {
 145                         Object result = null;
 146                         if (b.type().isReferable()) {
 147                                 result = map.get(b);
 148                                 if (result!=null) return result;
 149                         }
 150                         Object[] values = new Object[ b.getComponentCount() ];
 151                         result = b.createPartial();
 152                         if (b.type().isReferable()) map.put(b, result);
 153                         for (int i=0; i<values.length; i++) {
 154                                 Binding cb = b.getComponentBinding(i);
 155                                 values[i] = cb.accept(this);
 156                         }
 157                         b.setComponents(result, values);
 158                         return result;
 159                 } catch (BindingException e) {
 160                         throw new RuntimeBindingException(e);
 161                 }
 162         }
 163
 164         @Override
 165         public Object visit(StringBinding b) {
 166                 Object result = null;
 167                 StringType st = b.type();
 168                 if (st.getPattern() != null) {
 169                         // TODO Create a string that is valid to the pattern
 170                         result = b.createUnchecked("");
 171                 } else {
 172                         result = b.createUnchecked("");
 173                 }
 174                 return result;
 175         }
 176
 177         @Override
 178         public Object visit(UnionBinding b) {
 179                 int tag = 0;
 180                 Binding componentBinding = b.getComponentBinding(tag);
 181                 Object tag0defaultValue = componentBinding.accept(this);
 182                 return b.createUnchecked(tag, tag0defaultValue);
 183         }
 184
 185
 186         @Override
 187         public Object visit(VariantBinding b) {
 188                 Binding voidBinding = Bindings.getBindingUnchecked(void.class);
 189                 Object voidValue = null;
 190                 return b.createUnchecked(voidBinding, voidValue);
 191         }
 192
 193         @Override
 194         public Object visit(MapBinding b) {
 195                 return b.createUnchecked();
 196         }
 197
 198 }
 199