/interpreter/tags/reactive-pattern-matching/src/edu/vub/at/objects/natives/NATField.java
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 */ 28package edu.vub.at.objects.natives; 29 30import edu.vub.at.exceptions.InterpreterException; 31import edu.vub.at.exceptions.XIllegalOperation; 32import edu.vub.at.exceptions.XSelectorNotFound; 33import edu.vub.at.exceptions.XTypeMismatch; 34import edu.vub.at.objects.ATField; 35import edu.vub.at.objects.ATMutable; 36import edu.vub.at.objects.ATObject; 37import edu.vub.at.objects.ATTable; 38import edu.vub.at.objects.coercion.NativeTypeTags; 39import edu.vub.at.objects.grammar.ATSymbol; 40 41/** 42 * NATField implements a causally connected field of an object. Rather than storing 43 * these fields directly in every object, we choose to only make people pay when they 44 * choose to reify them. 45 * 46 * @author smostinc, tvcutsem 47 */ 48public class NATField extends NATByRef implements ATField, ATMutable { 49 50 private final ATSymbol name_; 51 private final ATObject host_; 52 53 /** 54 * Constructs a new native field object linked to the field of a base-level 55 * AmbientTalk object 56 */ 57 public NATField(ATSymbol name, ATObject host) { 58 name_ = name; 59 host_ = host; 60 } 61 62 public ATSymbol base_name() { 63 return name_; 64 } 65 66 public ATObject base_readField() throws InterpreterException { 67 try { 68 return host_.meta_invokeField(host_, name_); 69 } catch (XSelectorNotFound e) { 70 e.catchOnlyIfSelectorEquals(name_); 71 // Since the field was selected from the receiver, it should always be found 72 throw new XIllegalOperation("Incorrectly initialised field accessed", e); 73 } 74 } 75 76 public ATObject base_writeField(ATObject newValue) throws InterpreterException { 77 return host_.impl_invoke(host_, name_.asAssignmentSymbol(), NATTable.of(newValue)); 78 } 79 80 public NATText meta_print() throws InterpreterException { 81 return NATText.atValue("<field:"+name_.meta_print().javaValue+">"); 82 } 83 84 public boolean isNativeField() { 85 return true; 86 } 87 88 public ATField asField() throws XTypeMismatch { 89 return this; 90 } 91 92 /** 93 * Fields can be re-initialized when installed in an object that is being cloned. 94 * They expect the new owner of the field as the sole instance to their 'new' method 95 */ 96 public ATObject meta_newInstance(ATTable initargs) throws InterpreterException { 97 if (initargs.base_length() != NATNumber.ONE) { 98 return super.meta_newInstance(initargs); 99 } else { 100 ATObject newhost = initargs.base_at(NATNumber.ONE); 101 return new NATField(name_, (NATCallframe) newhost); 102 } 103 } 104 105 public ATTable meta_typeTags() throws InterpreterException { 106 return NATTable.of(NativeTypeTags._FIELD_); 107 } 108 109}