/interpreter/tags/reactive-pattern-matching/src/edu/vub/at/objects/symbiosis/JavaField.java

  1/**
  2 * AmbientTalk/2 Project
  3 * JavaField.java created on 5-nov-2006 at 20:08:18
  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.symbiosis;
 29
 30import edu.vub.at.eval.Evaluator;
 31import edu.vub.at.exceptions.InterpreterException;
 32import edu.vub.at.exceptions.XIllegalArgument;
 33import edu.vub.at.objects.ATField;
 34import edu.vub.at.objects.ATMutable;
 35import edu.vub.at.objects.ATObject;
 36import edu.vub.at.objects.ATTable;
 37import edu.vub.at.objects.coercion.NativeTypeTags;
 38import edu.vub.at.objects.grammar.ATSymbol;
 39import edu.vub.at.objects.mirrors.Reflection;
 40import edu.vub.at.objects.natives.NATByRef;
 41import edu.vub.at.objects.natives.NATNumber;
 42import edu.vub.at.objects.natives.NATTable;
 43import edu.vub.at.objects.natives.NATText;
 44
 45import java.lang.reflect.Field;
 46
 47/**
 48 * A JavaField is a simple wrapper around a native java.lang.reflect.Field
 49 * 
 50 * @author tvcutsem
 51 */
 52public final class JavaField extends NATByRef implements ATField, ATMutable {
 53
 54	private final Object host_;
 55	private final Field field_;
 56
 57	public JavaField(Object host, Field f) {
 58		host_ = host;
 59		field_ = f;
 60	}
 61
 62	public ATSymbol base_name() {
 63		return Reflection.downSelector(field_.getName());
 64	}
 65
 66	public ATObject base_readField() throws InterpreterException {
 67		return Symbiosis.readField(host_, field_);
 68	}
 69
 70	public ATObject base_writeField(ATObject newValue) throws InterpreterException {
 71		Symbiosis.writeField(host_, field_, newValue);
 72		return Evaluator.getNil();
 73	}
 74
 75	public NATText meta_print() throws InterpreterException {
 76		return NATText.atValue("<java field:"+field_+">");
 77	}
 78	
 79	public ATField asField() {
 80		return this;
 81	}
 82	
 83	/**
 84	 * Fields can be re-initialized when installed in an object that is being cloned.
 85	 * They expect the new owner of the field as the sole instance to their 'new' method
 86	 */
 87	public ATObject meta_newInstance(ATTable initargs) throws InterpreterException {
 88		if (initargs.base_length() != NATNumber.ONE) {
 89			return super.meta_newInstance(initargs);
 90		} else {
 91			ATObject newhost = initargs.base_at(NATNumber.ONE);
 92			if (newhost.isJavaObjectUnderSymbiosis()) {
 93				return new JavaField(newhost.asJavaObjectUnderSymbiosis().getWrappedObject(), field_);
 94			} else {
 95				throw new XIllegalArgument("Java Field re-initialization requires a symbiotic Java object, given " + newhost);
 96			}
 97		}
 98	}
 99	
100    public ATTable meta_typeTags() throws InterpreterException {
101    	return NATTable.of(NativeTypeTags._FIELD_);
102    }
103    	
104}