/interpreter/tags/at2dist090708/src/edu/vub/at/objects/natives/NATField.java
Java | 151 lines | 91 code | 17 blank | 43 comment | 3 complexity | 2300cbe450d01363cc09e9b6d091388d 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.eval.Evaluator; 31import edu.vub.at.exceptions.InterpreterException; 32import edu.vub.at.exceptions.XIllegalOperation; 33import edu.vub.at.exceptions.XSelectorNotFound; 34import edu.vub.at.exceptions.XTypeMismatch; 35import edu.vub.at.objects.ATContext; 36import edu.vub.at.objects.ATField; 37import edu.vub.at.objects.ATMethod; 38import edu.vub.at.objects.ATObject; 39import edu.vub.at.objects.ATTable; 40import edu.vub.at.objects.coercion.NativeTypeTags; 41import edu.vub.at.objects.grammar.ATSymbol; 42import edu.vub.at.objects.mirrors.PrimitiveMethod; 43import edu.vub.at.objects.natives.grammar.AGSymbol; 44 45/** 46 * NATField implements a causally connected field of an object. Rather than storing 47 * these fields directly in every object, we choose to only make people pay when they 48 * choose to reify them. 49 * 50 * @author smostinc, tvcutsem 51 */ 52public class NATField extends NATByRef implements ATField { 53 54 private final ATSymbol name_; 55 private final ATObject host_; 56 57 /** 58 * Constructs a new native field object linked to the field of a base-level 59 * AmbientTalk object 60 */ 61 public NATField(ATSymbol name, ATObject host) { 62 name_ = name; 63 host_ = host; 64 } 65 66 public ATSymbol base_name() { 67 return name_; 68 } 69 70 public ATObject base_readField() throws InterpreterException { 71 try { 72 return host_.meta_invokeField(host_, name_); 73 } catch (XSelectorNotFound e) { 74 e.catchOnlyIfSelectorEquals(name_); 75 // Since the field was selected from the receiver, it should always be found 76 throw new XIllegalOperation("Incorrectly initialised field accessed", e); 77 } 78 } 79 80 public ATObject base_writeField(ATObject newValue) throws InterpreterException { 81 return host_.impl_invoke(host_, name_.asAssignmentSymbol(), NATTable.of(newValue)); 82 } 83 84 public NATText meta_print() throws InterpreterException { 85 return NATText.atValue("<field:"+name_.meta_print().javaValue+">"); 86 } 87 88 public boolean isNativeField() { 89 return true; 90 } 91 92 public ATField asField() throws XTypeMismatch { 93 return this; 94 } 95 96 /** 97 * Fields can be re-initialized when installed in an object that is being cloned. 98 * They expect the new owner of the field as the sole instance to their 'new' method 99 */ 100 public ATObject meta_newInstance(ATTable initargs) throws InterpreterException { 101 if (initargs.base_length() != NATNumber.ONE) { 102 return super.meta_newInstance(initargs); 103 } else { 104 ATObject newhost = initargs.base_at(NATNumber.ONE); 105 return new NATField(name_, (NATCallframe) newhost); 106 } 107 } 108 109 public ATTable meta_typeTags() throws InterpreterException { 110 return NATTable.of(NativeTypeTags._FIELD_); 111 } 112 113 public ATMethod base_accessor() throws InterpreterException { 114 return accessorForField(this); 115 } 116 117 public ATMethod base_mutator() throws InterpreterException { 118 return mutatorForField(this); 119 } 120 121 public static ATMethod accessorForField(final ATField f) throws InterpreterException { 122 return new PrimitiveMethod(f.base_name(), NATTable.EMPTY, new PrimitiveMethod.PrimitiveBody() { 123 public ATObject meta_eval(ATContext ctx) throws InterpreterException { 124 return f.base_readField(); 125 } 126 public NATText meta_print() throws InterpreterException { 127 return NATText.atValue(f.base_readField().toString()); 128 } 129 }) { 130 public NATText meta_print() throws InterpreterException { 131 return NATText.atValue("<accessor method for:"+f.base_name()+">"); 132 } 133 }; 134 } 135 136 public static ATMethod mutatorForField(final ATField f) throws InterpreterException { 137 return new PrimitiveMethod(f.base_name().asAssignmentSymbol(), NATTable.of(AGSymbol.jAlloc("v")), new PrimitiveMethod.PrimitiveBody() { 138 public ATObject meta_eval(ATContext ctx) throws InterpreterException { 139 return f.base_writeField(ctx.base_lexicalScope().impl_callField(AGSymbol.jAlloc("v"))); 140 } 141 public NATText meta_print() throws InterpreterException { 142 return NATText.atValue(""+f.base_name()+" := v"); 143 } 144 }) { 145 public NATText meta_print() throws InterpreterException { 146 return NATText.atValue("<mutator method for:"+f.base_name()+">"); 147 } 148 }; 149 } 150 151}