expnavigation.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 java.util.Iterator;
import java.util.List;

import org.tzi.use.uml.mm.MNavigableElement;
import org.tzi.use.uml.ocl.type.ObjectType;
import org.tzi.use.uml.ocl.type.SequenceType;
import org.tzi.use.uml.ocl.type.SetType;
import org.tzi.use.uml.ocl.type.Type;
import org.tzi.use.uml.ocl.value.ObjectValue;
import org.tzi.use.uml.ocl.value.SequenceValue;
import org.tzi.use.uml.ocl.value.SetValue;
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.uml.sys.MSystemState;

/**
 * Navigation expression from one class to another.
 *
 * @version     $ProjectVersion: 2-3-0-release.1 $
 * @author  Mark Richters
 */
public final class ExpNavigation extends Expression {
    private MNavigableElement fSrc;
    private MNavigableElement fDst;
    private Expression fObjExp;
    
    public ExpNavigation(Expression objExp,
                         MNavigableElement src,
                         MNavigableElement dst)
        throws ExpInvalidException
    {
        // set result type later
        super(null);

        // let c be the class at dstEnd, then the result type is:
        // (1) c if the multiplicity is max. one and this is binary association
        // (2) Set(c) if the multiplicity is greater than 1 
        // (3) Sequence(c) if the association end is marked as {ordered}

        setResultType( dst.getType( src ) );

        fSrc = src;
        fDst = dst;
        fObjExp = objExp;
        if ( !objExp.type().isObjectType() )
            throw new ExpInvalidException(
                    "Target expression of navigation operation must have " +
                    "object type, found `" + objExp.type() + "'." );

    }

    /**
     * Evaluates expression and returns result value.
     */
    public Value eval(EvalContext ctx) {
        ctx.enter(this);
        Value res = new UndefinedValue(type());
        Value val = fObjExp.eval(ctx);

        // if we don't have an object we can't navigate 
        if (! val.isUndefined() ) {
            // get the object
            ObjectValue objVal = (ObjectValue) val;
            MObject obj = objVal.value();
            MSystemState state = isPre() ? ctx.preState() : ctx.postState();
            MObjectState objState = obj.state(state);

            // get objects at association end
            List objList = obj.getNavigableObjects(state, fSrc, fDst);
            Type resultType = type();
            if (resultType.isObjectType() ) {
                if (objList.size() > 1 )
                    throw new MultiplicityViolationException(
                        "expected link set size 1 at " + 
                        "association end `" + fDst + 
                        "', found: " + 
                        objList.size());
                if (objList.size() == 1 ) {
                    obj = (MObject) objList.get(0);
                    if (obj.exists(state) )
                        res = new ObjectValue((ObjectType) type(), obj);
                }
            } else if (resultType.isSet() ) {
                res = new SetValue(((SetType) resultType).elemType(), 
                                   oidsToObjectValues(state, objList));
            } else if (resultType.isSequence() ) {
                res = new SequenceValue(((SequenceType) resultType).elemType(), 
                                        oidsToObjectValues(state, objList));
            } else
                throw new RuntimeException("Unexpected association end type `" + 
                                           resultType + "'");
        }

        ctx.exit(this, res);
        return res;
    }

    private Value[] oidsToObjectValues(MSystemState state, List objList) {
        Value[] res = new ObjectValue[objList.size()];
        Iterator it = objList.iterator();
        int i = 0;
        while (it.hasNext() ) {
            MObject obj = (MObject) it.next();
            MObjectState objState = obj.state(state);
            if (objState != null )
                res[i++] = new ObjectValue(obj.type(), obj);
        }
        return res;
    }


    public String toString() {
        return fObjExp + "." + fDst.nameAsRolename() + atPre();
    }
}