Association.cc

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/*
 * Association.cc
 *
 * Smalltalk like class library for C++
 * Relation between two objects.
 *
 * Copyright (c) 2003 Milan Cermak
 */
/*
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
#include <stlib/Association.h>
#include <stlib/String.h>
#include <stlib/Stream.h>
#include <stlib/Visitor.h>

Association::Association(Object *key, Object *value)
{
    _key = key;
    _value = value;
}

/* Copying protocol */
Association::Association(const Association &origin)
  : Object(origin)
{
    _key = origin._key;
    _value = origin._value;
}

/* Class-accessing protocol */
String *Association::className(void) const
{
    return new String("Association");
}

/* Accessing protocol */
void Association::key(Object *object)
{
    _key = object;
}

Object *Association::key(void)
{
    return _key;
}

void Association::value(Object *object)
{
    _value = object;
}

Object *Association::value(void)
{
    return _value;
}

/* Comparing protocol */
long Association::hash(void) const
{
    if (_key == nil) return Object::hash();
                else return _key->hash();
}

bool Association::isEqual(const Object *object) const
{
    if (object->isAssociation() && Object::isEqual(object)) {
        return _key == ((Association *) object)->key() &&
               _value == ((Association *) object)->value();
    }
    return false;
}

/* Copying protocol */
Object *Association::copy(void)
{
    return new Association(*this);
}

/* Printing protocol */
void Association::printOn(Stream *stream) const
{
    stream->print(_key);
    stream->nextPutAll("->");
    if (_value == nil) stream->nextPutAll("nil");
                  else stream->print(_value);
}

/* Testing protocol */
bool Association::isAssociation(void) const
{
    return true;
}

/* Visiting protocol */
void Association::visitBy(Visitor *visitor)
{
    visitor->visitAssociation(this);
}

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