/interpreter/tags/at_build150307/src/edu/vub/at/objects/natives/NATField.java

http://ambienttalk.googlecode.com/ · Java · 103 lines · 51 code · 13 blank · 39 comment · 3 complexity · 4fe7080d9b0e615da09e2ae8f995facc 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.XTypeMismatch;
  32. import edu.vub.at.objects.ATField;
  33. import edu.vub.at.objects.ATNil;
  34. import edu.vub.at.objects.ATObject;
  35. import edu.vub.at.objects.ATTable;
  36. import edu.vub.at.objects.coercion.NativeStripes;
  37. import edu.vub.at.objects.grammar.ATSymbol;
  38. /**
  39. * NATField implements a causally connected field of an object. Rather than storing
  40. * these fields directly in every object, we choose to only make people pay when they
  41. * choose to reify them.
  42. *
  43. * @author smostinc
  44. */
  45. public class NATField extends NATByRef implements ATField {
  46. private final ATSymbol name_;
  47. private final NATCallframe frame_;
  48. public NATField(ATSymbol name, NATCallframe frame) {
  49. name_ = name;
  50. frame_ = frame;
  51. }
  52. public ATSymbol base_getName() {
  53. return name_;
  54. }
  55. public ATObject base_readField() throws InterpreterException {
  56. try {
  57. return frame_.getLocalField(name_);
  58. } catch (InterpreterException e) {
  59. // Since the field was selected from the receiver, it should always be found
  60. throw new XIllegalOperation("Incorrectly initialised field accessed", e);
  61. }
  62. }
  63. public ATNil base_writeField(ATObject newValue) throws InterpreterException {
  64. return frame_.meta_assignField(frame_, name_, newValue);
  65. }
  66. public NATText meta_print() throws InterpreterException {
  67. return NATText.atValue("<field:"+name_.meta_print().javaValue+">");
  68. }
  69. public boolean isNativeField() {
  70. return true;
  71. }
  72. public ATField asField() throws XTypeMismatch {
  73. return this;
  74. }
  75. /**
  76. * Fields can be re-initialized when installed in an object that is being cloned.
  77. * They expect the new owner of the field as the sole instance to their 'new' method
  78. */
  79. public ATObject meta_newInstance(ATTable initargs) throws InterpreterException {
  80. if (initargs.base_getLength() != NATNumber.ONE) {
  81. return super.meta_newInstance(initargs);
  82. } else {
  83. ATObject newhost = initargs.base_at(NATNumber.ONE);
  84. return new NATField(name_, (NATCallframe) newhost);
  85. }
  86. }
  87. public ATTable meta_getStripes() throws InterpreterException {
  88. return NATTable.of(NativeStripes._FIELD_);
  89. }
  90. }