/interpreter/tags/at2dist130208/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.exceptions.InterpreterException;
 31import edu.vub.at.exceptions.XIllegalArgument;
 32import edu.vub.at.objects.ATField;
 33import edu.vub.at.objects.ATObject;
 34import edu.vub.at.objects.ATTable;
 35import edu.vub.at.objects.coercion.NativeTypeTags;
 36import edu.vub.at.objects.grammar.ATSymbol;
 37import edu.vub.at.objects.mirrors.Reflection;
 38import edu.vub.at.objects.natives.NATByRef;
 39import edu.vub.at.objects.natives.OBJNil;
 40import edu.vub.at.objects.natives.NATNumber;
 41import edu.vub.at.objects.natives.NATTable;
 42import edu.vub.at.objects.natives.NATText;
 43
 44import java.lang.reflect.Field;
 45
 46/**
 47 * A JavaField is a simple wrapper around a native java.lang.reflect.Field
 48 * 
 49 * @author tvcutsem
 50 */
 51public final class JavaField extends NATByRef implements ATField {
 52
 53	private final Object host_;
 54	private final Field field_;
 55
 56	public JavaField(Object host, Field f) {
 57		host_ = host;
 58		field_ = f;
 59	}
 60
 61	public ATSymbol base_name() {
 62		return Reflection.downSelector(field_.getName());
 63	}
 64
 65	public ATObject base_readField() throws InterpreterException {
 66		return Symbiosis.readField(host_, field_);
 67	}
 68
 69	public ATObject base_writeField(ATObject newValue) throws InterpreterException {
 70		Symbiosis.writeField(host_, field_, newValue);
 71		return OBJNil._INSTANCE_;
 72	}
 73
 74	public NATText meta_print() throws InterpreterException {
 75		return NATText.atValue("<java field:"+field_+">");
 76	}
 77	
 78	public ATField asField() {
 79		return this;
 80	}
 81	
 82	/**
 83	 * Fields can be re-initialized when installed in an object that is being cloned.
 84	 * They expect the new owner of the field as the sole instance to their 'new' method
 85	 */
 86	public ATObject meta_newInstance(ATTable initargs) throws InterpreterException {
 87		if (initargs.base_length() != NATNumber.ONE) {
 88			return super.meta_newInstance(initargs);
 89		} else {
 90			ATObject newhost = initargs.base_at(NATNumber.ONE);
 91			if (newhost.isJavaObjectUnderSymbiosis()) {
 92				return new JavaField(newhost.asJavaObjectUnderSymbiosis().getWrappedObject(), field_);
 93			} else {
 94				throw new XIllegalArgument("Java Field re-initialization requires a symbiotic Java object, given " + newhost);
 95			}
 96		}
 97	}
 98	
 99    public ATTable meta_typeTags() throws InterpreterException {
100    	return NATTable.of(NativeTypeTags._FIELD_);
101    }
102    	
103}