/interpreter/tags/at2dist130208/src/edu/vub/at/objects/natives/NATTypeTag.java

http://ambienttalk.googlecode.com/ · Java · 196 lines · 96 code · 26 blank · 74 comment · 11 complexity · e5e69126b133896f5e9c70e171994128 MD5 · raw file

  1. /**
  2. * AmbientTalk/2 Project
  3. * NATTypeTag.java created on 18-feb-2007 at 15:59:20
  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.actors.natives.DiscoveryManager;
  30. import edu.vub.at.exceptions.InterpreterException;
  31. import edu.vub.at.objects.ATBoolean;
  32. import edu.vub.at.objects.ATObject;
  33. import edu.vub.at.objects.ATTable;
  34. import edu.vub.at.objects.ATTypeTag;
  35. import edu.vub.at.objects.coercion.NativeTypeTags;
  36. import edu.vub.at.objects.grammar.ATSymbol;
  37. import edu.vub.at.objects.mirrors.NativeClosure;
  38. import edu.vub.at.objects.natives.grammar.AGSymbol;
  39. /**
  40. * The native implementation of AmbientTalk type tag objects.
  41. *
  42. * In principle, care should be taken that all objects implementing the
  43. * type tag interface are isolates, because type tags are usually attributed
  44. * to messages which are isolates themselves.
  45. *
  46. * @author tvcutsem
  47. */
  48. public class NATTypeTag extends NATByCopy implements ATTypeTag {
  49. private final ATSymbol typeName_;
  50. private final ATTable parentTypes_;
  51. public static ATTypeTag[] toTypeTagArray(ATTable types) throws InterpreterException {
  52. if (types == NATTable.EMPTY) {
  53. return NATObject._NO_TYPETAGS_;
  54. }
  55. ATObject[] unwrapped = types.asNativeTable().elements_;
  56. ATTypeTag[] unwrappedTypes = new ATTypeTag[unwrapped.length];
  57. for (int i = 0; i < unwrappedTypes.length; i++) {
  58. unwrappedTypes[i] = unwrapped[i].asTypeTag();
  59. }
  60. return unwrappedTypes;
  61. }
  62. public static NATTypeTag atValue(String typeName) {
  63. return atValue(AGSymbol.jAlloc(typeName));
  64. }
  65. public static NATTypeTag atValue(ATSymbol typeName) {
  66. return new NATTypeTag(typeName,
  67. NATTable.atValue(new ATObject[] { OBJRootType._INSTANCE_ }));
  68. }
  69. public static NATTypeTag atValue(String typeName, NATTypeTag singleParent) {
  70. return new NATTypeTag(AGSymbol.jAlloc(typeName),
  71. NATTable.atValue(new ATObject[] { singleParent }));
  72. }
  73. /**
  74. * Types should not be created directly because it should be verified
  75. * that their list of parent types is never empty. Types created
  76. * with an empty parent list automatically get assigned the root type
  77. * as their single parent.
  78. */
  79. public static NATTypeTag atValue(ATSymbol typeName, ATTable parentTypes) {
  80. if (parentTypes == NATTable.EMPTY) {
  81. return new NATTypeTag(typeName, NATTable.atValue(new ATObject[] { OBJRootType._INSTANCE_ }));
  82. } else {
  83. return new NATTypeTag(typeName, parentTypes);
  84. }
  85. }
  86. /**
  87. * The constructor is declared protected such that it cannot be used externally,
  88. * but can be used by the OBJRootType class to create a type with an empty
  89. * parent table, which is normally not allowed. Hence, by construction the only
  90. * type with an empty parent table is the root type.
  91. */
  92. protected NATTypeTag(ATSymbol typeName, ATTable parentTypes) {
  93. typeName_ = typeName;
  94. parentTypes_ = parentTypes;
  95. }
  96. public ATSymbol base_typeName() throws InterpreterException {
  97. return typeName_;
  98. }
  99. public ATTable base_superTypes() throws InterpreterException {
  100. return parentTypes_;
  101. }
  102. /**
  103. * Native implementation of:
  104. *
  105. * def isSubtypeOf(supertype) {
  106. * (supertype.name() == name).or:
  107. * { (supertypes.find: { |type|
  108. * type.isSubtypeOf(supertype) }) != nil }
  109. * };
  110. */
  111. public ATBoolean base_isSubtypeOf(final ATTypeTag supertype) throws InterpreterException {
  112. if (supertype.base_typeName().equals(typeName_)) {
  113. return NATBoolean._TRUE_;
  114. } else {
  115. ATObject found = parentTypes_.base_find_(new NativeClosure(this) {
  116. public ATObject base_apply(ATTable args) throws InterpreterException {
  117. ATTypeTag type = get(args, 1).asTypeTag();
  118. return type.base_isSubtypeOf(supertype);
  119. }
  120. });
  121. return NATBoolean.atValue(found != OBJNil._INSTANCE_);
  122. }
  123. }
  124. /**
  125. * Identity of types is based on their name
  126. */
  127. public ATBoolean base__opeql__opeql_(ATObject comparand) throws InterpreterException {
  128. if (comparand.isTypeTag()) {
  129. return comparand.asTypeTag().base_typeName().base__opeql__opeql_(typeName_);
  130. } else {
  131. return NATBoolean._FALSE_;
  132. }
  133. }
  134. public boolean isTypeTag() { return true; }
  135. public ATTypeTag asTypeTag() { return this; }
  136. public NATText meta_print() throws InterpreterException {
  137. return NATText.atValue("<type tag:"+typeName_+">");
  138. }
  139. /**
  140. * Types are singletons
  141. */
  142. public ATObject meta_clone() throws InterpreterException {
  143. return this;
  144. }
  145. public ATTable meta_typeTags() throws InterpreterException {
  146. return NATTable.of(NativeTypeTags._TYPETAG_, NativeTypeTags._ISOLATE_);
  147. }
  148. /** required as type tags are stored in a hashset in the {@link DiscoveryManager} */
  149. public int hashCode() { return typeName_.hashCode(); }
  150. /**
  151. * The root type of the type hierarchy: every type eventually
  152. * has this type as its parent.
  153. */
  154. public static class OBJRootType extends NATTypeTag implements ATTypeTag {
  155. private final static AGSymbol _ROOT_NAME_ = AGSymbol.jAlloc("Type");
  156. public static final OBJRootType _INSTANCE_ = new OBJRootType();
  157. /**
  158. * The root type is named `Type and has no parent types
  159. */
  160. private OBJRootType() {
  161. super(_ROOT_NAME_, NATTable.EMPTY);
  162. }
  163. /**
  164. * The root type is only a subtype of the root type itself
  165. */
  166. public ATBoolean base_isSubtypeOf(ATTypeTag supertype) throws InterpreterException {
  167. return NATBoolean.atValue(supertype.base_typeName().equals(_ROOT_NAME_));
  168. }
  169. }
  170. }