expobjop.java

UML设计测试工具

/*
 * USE - UML based specification environment
 * Copyright (C) 1999-2004 Mark Richters, University of Bremen
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/* $ProjectHeader: use 2-3-0-release.1 Mon, 12 Sep 2005 20:18:33 +0200 green $ */

package org.tzi.use.uml.ocl.expr;

import org.tzi.use.uml.mm.MClass;
import org.tzi.use.uml.mm.MOperation;
import org.tzi.use.uml.ocl.value.ObjectValue;
import org.tzi.use.uml.ocl.value.UndefinedValue;
import org.tzi.use.uml.ocl.value.Value;
import org.tzi.use.uml.sys.MObject;
import org.tzi.use.uml.sys.MObjectState;
import org.tzi.use.util.StringUtil;

/**
 * An operation defined by a class.
 *
 * @version     $ProjectVersion: 2-3-0-release.1 $
 * @author  Mark Richters
 */
public final class ExpObjOp extends Expression {
    private MOperation fOp;
    private Expression[] fArgs; // the arguments, first one is "receiver" object
    
    public ExpObjOp(MOperation op, Expression[] args) 
        throws ExpInvalidException
    {
        super(op.resultType());
        fOp = op;
        fArgs = args;
        if (! args[0].type().isObjectType() )
            throw new ExpInvalidException(
                                          "Target expression of object operation must have " +
                                          "object type, found `" + args[0].type() + "'.");

        // check for matching arguments
        VarDeclList params = fOp.paramList();
        if (params.size() != (args.length - 1) )
            throw new ExpInvalidException(
                                          "Number of arguments does not match declaration of operation `" +
                                          fOp.name() + "'. Expected " + params.size() + " argument(s), found " +
                                          (args.length - 1) + ".");

        for (int i = 1; i < args.length; i++)
            if (! args[i].type().isSubtypeOf(params.varDecl(i - 1).type()) )
                throw new ExpInvalidException(
                                              "Type mismatch in argument `" + params.varDecl(i - 1).name() + 
                                              "'. Expected type `" + params.varDecl(i - 1).type() + 
                                              "', found `" + args[i].type() + "'.");
    }

    /**
     * Evaluates expression and returns result value.
     */
    public Value eval(EvalContext ctx) {
        ctx.enter(this);
        Value res = new UndefinedValue(type());
        Value val = fArgs[0].eval(ctx);
        // if we don't have an object we can't call its operation
        if (! val.isUndefined() ) {
            // get object
            ObjectValue objVal = (ObjectValue) val;
            MObject obj = objVal.value();
            MObjectState objState = isPre() ? 
                obj.state(ctx.preState()) : obj.state(ctx.postState());
            if (objState != null ) {
                // the object's type may be a subtype of the declared
                // type. The operation may be redefined in this
                // subclass. We have to get the possibly redefined
                // operation.
                MClass cls = obj.cls();
                MOperation op = cls.operation(fOp.name(), true);

                // evaluate arguments
                Value [] argValues = new Value[fArgs.length - 1];
                for (int i = 0; i < fArgs.length - 1; i++)
                    argValues[i] = fArgs[i + 1].eval(ctx);

                // bind the argument values to the operation's
                // parameters
                VarDeclList params = op.paramList();
                for (int i = 0; i < fArgs.length - 1; i++) {
                    VarDecl decl = params.varDecl(i);
                    ctx.pushVarBinding(decl.name(), argValues[i]);
                }

                // the operation's expression must be evaluated in context
                // of the target object. The "self" variable is bound to
                // the receiver object.
                ctx.pushVarBinding("self", objVal);
                Expression opExpr = op.expression();
                res = opExpr.eval(ctx);
                ctx.popVarBinding();
                for (int i = 1; i < fArgs.length; i++) 
                    ctx.popVarBinding();
            }
        }
        ctx.exit(this, res);
        return res;
    }

    public String toString() {
        return fArgs[0] + "." + fOp.name() + atPre() +
            "(" + StringUtil.fmtSeq(fArgs, 1, ", ") + ")";
    }
}