/interpreter/tags/reactive-pattern-matching/src/edu/vub/at/objects/natives/NATField.java

http://ambienttalk.googlecode.com/ · Java · 109 lines · 53 code · 13 blank · 43 comment · 3 complexity · c04fef25303960a87c94ea03fbc5c39e MD5 · raw file

  1. /**
  2. * AmbientTalk/2 Project
  3. * NATField.java created on Jul 27, 2006 at 2:27:53 AM
  4. * (c) Programming Technology Lab, 2006 - 2007
  5. * Authors: Tom Van Cutsem & Stijn Mostinckx
  6. *
  7. * Permission is hereby granted, free of charge, to any person
  8. * obtaining a copy of this software and associated documentation
  9. * files (the "Software"), to deal in the Software without
  10. * restriction, including without limitation the rights to use,
  11. * copy, modify, merge, publish, distribute, sublicense, and/or
  12. * sell copies of the Software, and to permit persons to whom the
  13. * Software is furnished to do so, subject to the following
  14. * conditions:
  15. *
  16. * The above copyright notice and this permission notice shall be
  17. * included in all copies or substantial portions of the Software.
  18. *
  19. * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  20. * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
  21. * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  22. * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
  23. * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
  24. * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  25. * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  26. * OTHER DEALINGS IN THE SOFTWARE.
  27. */
  28. package edu.vub.at.objects.natives;
  29. import edu.vub.at.exceptions.InterpreterException;
  30. import edu.vub.at.exceptions.XIllegalOperation;
  31. import edu.vub.at.exceptions.XSelectorNotFound;
  32. import edu.vub.at.exceptions.XTypeMismatch;
  33. import edu.vub.at.objects.ATField;
  34. import edu.vub.at.objects.ATMutable;
  35. import edu.vub.at.objects.ATObject;
  36. import edu.vub.at.objects.ATTable;
  37. import edu.vub.at.objects.coercion.NativeTypeTags;
  38. import edu.vub.at.objects.grammar.ATSymbol;
  39. /**
  40. * NATField implements a causally connected field of an object. Rather than storing
  41. * these fields directly in every object, we choose to only make people pay when they
  42. * choose to reify them.
  43. *
  44. * @author smostinc, tvcutsem
  45. */
  46. public class NATField extends NATByRef implements ATField, ATMutable {
  47. private final ATSymbol name_;
  48. private final ATObject host_;
  49. /**
  50. * Constructs a new native field object linked to the field of a base-level
  51. * AmbientTalk object
  52. */
  53. public NATField(ATSymbol name, ATObject host) {
  54. name_ = name;
  55. host_ = host;
  56. }
  57. public ATSymbol base_name() {
  58. return name_;
  59. }
  60. public ATObject base_readField() throws InterpreterException {
  61. try {
  62. return host_.meta_invokeField(host_, name_);
  63. } catch (XSelectorNotFound e) {
  64. e.catchOnlyIfSelectorEquals(name_);
  65. // Since the field was selected from the receiver, it should always be found
  66. throw new XIllegalOperation("Incorrectly initialised field accessed", e);
  67. }
  68. }
  69. public ATObject base_writeField(ATObject newValue) throws InterpreterException {
  70. return host_.impl_invoke(host_, name_.asAssignmentSymbol(), NATTable.of(newValue));
  71. }
  72. public NATText meta_print() throws InterpreterException {
  73. return NATText.atValue("<field:"+name_.meta_print().javaValue+">");
  74. }
  75. public boolean isNativeField() {
  76. return true;
  77. }
  78. public ATField asField() throws XTypeMismatch {
  79. return this;
  80. }
  81. /**
  82. * Fields can be re-initialized when installed in an object that is being cloned.
  83. * They expect the new owner of the field as the sole instance to their 'new' method
  84. */
  85. public ATObject meta_newInstance(ATTable initargs) throws InterpreterException {
  86. if (initargs.base_length() != NATNumber.ONE) {
  87. return super.meta_newInstance(initargs);
  88. } else {
  89. ATObject newhost = initargs.base_at(NATNumber.ONE);
  90. return new NATField(name_, (NATCallframe) newhost);
  91. }
  92. }
  93. public ATTable meta_typeTags() throws InterpreterException {
  94. return NATTable.of(NativeTypeTags._FIELD_);
  95. }
  96. }