/interpreter/tags/at2dist220411/src/edu/vub/at/objects/natives/NATDelegation.java

  1/**
  2 * AmbientTalk/2 Project
  3 * NATDelegation.java created on 29-jan-2007 at 16:24:59
  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.objects.ATMessage;
 33import edu.vub.at.objects.ATMethodInvocation;
 34import edu.vub.at.objects.ATObject;
 35import edu.vub.at.objects.ATTypeTag;
 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.natives.grammar.AGSymbol;
 40import edu.vub.util.TempFieldGenerator;
 41
 42import java.util.LinkedList;
 43import java.util.Set;
 44import java.util.Vector;
 45
 46/**
 47 * Instances of the class NATMethodInvocation represent first-class method invocations.
 48 * They encapsulate a selector and arguments and may be turned into an actual invocation by invoking meta_sendTo.
 49 * This method provides the invocation with a receiver to apply itself to.
 50 * 
 51 * @author tvcutsem
 52 */
 53public final class NATDelegation extends NATMessage implements ATMethodInvocation {
 54
 55	private final static AGSymbol _DELEGATOR_ = AGSymbol.jAlloc("delegator");
 56	
 57	public NATDelegation(ATObject delegator, ATSymbol sel, ATTable arg, ATTable annotations) throws InterpreterException {
 58		super(sel, arg, annotations, NativeTypeTags._DELEGATION_);
 59		super.meta_defineField(_DELEGATOR_, delegator);
 60	}
 61	
 62    /**
 63     * Copy constructor.
 64     */
 65    private NATDelegation(FieldMap map,
 66            Vector state,
 67            LinkedList originalCustomFields,
 68            MethodDictionary methodDict,
 69            ATObject dynamicParent,
 70            ATObject lexicalParent,
 71            byte flags,
 72            ATTypeTag[] types,
 73            Set freeVars) throws InterpreterException {
 74    	super(map, state, originalCustomFields, methodDict, dynamicParent, lexicalParent, flags, types, freeVars);
 75    }
 76
 77    public ATMethodInvocation asMethodInvocation() { return this; }
 78    
 79	/**
 80	 * To evaluate a delegating message send, invoke the method corresponding to the encapsulated
 81	 * selector with the encapsulated arguments. During execution of the method, 'self' should be
 82	 * bound to the object that initiated the delegating method invocation.
 83	 * 
 84	 * @return the return value of the invoked method.
 85	 */
 86	public ATObject prim_sendTo(ATMessage self, ATObject receiver, ATObject sender) throws InterpreterException {
 87		return receiver.meta_invoke(super.meta_invokeField(self, _DELEGATOR_), self.asMethodInvocation());
 88	}
 89	
 90	public NATText meta_print() throws InterpreterException {
 91		return NATText.atValue("<delegation:"+base_selector()+Evaluator.printAsList(base_arguments()).javaValue+">");
 92	}
 93	
 94	public NATText impl_asCode(TempFieldGenerator objectMap) throws InterpreterException {
 95		if (objectMap.contains(this)) {
 96			return objectMap.getName(this);
 97		}
 98		//StringBuffer codeString = new StringBuffer("^" + base_selector().meta_print().javaValue + Evaluator.printAsList(base_arguments()).javaValue);
 99		StringBuffer codeString = new StringBuffer("^" + base_selector().meta_print().javaValue + Evaluator.codeAsList(objectMap, base_arguments()).javaValue);
100		NATTable annotations = NATTable.atValue(this.typeTags_);
101		if(annotations.base_length().asNativeNumber().javaValue > 0) {
102			codeString.append("@"+annotations.impl_asCode(objectMap).javaValue);
103		}
104		NATText code = NATText.atValue(codeString.toString());
105		NATText name = objectMap.put(this, code);
106		return name;
107	}
108	
109	protected NATObject createClone(FieldMap map,
110			Vector state,
111			LinkedList originalCustomFields,
112			MethodDictionary methodDict,
113			ATObject dynamicParent,
114			ATObject lexicalParent,
115			byte flags,
116			ATTypeTag[] types,
117			Set freeVars) throws InterpreterException {
118		return new NATDelegation(map,
119				state,
120				originalCustomFields,
121				methodDict,
122				dynamicParent,
123				lexicalParent,
124				flags,
125				types,
126				freeVars);
127	}
128	
129}