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AbstractMap.java

package ca.mcgill.sable.util;

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * SableUtil, a clean room implementation of the Collection API.     *
 * Copyright (C) 1997, 1998 Etienne Gagnon (gagnon@sable.mcgill.ca). *
 * All rights reserved.                                              *
 *                                                                   *
 * This work was done as a project of the Sable Research Group,      *
 * School of Computer Science, McGill University, Canada             *
 * (http://www.sable.mcgill.ca/).  It is understood that any         *
 * modification not identified as such is not covered by the         *
 * preceding statement.                                              *
 *                                                                   *
 * This work is free software; you can redistribute it and/or        *
 * modify it under the terms of the GNU Library General Public       *
 * License as published by the Free Software Foundation; either      *
 * version 2 of the License, or (at your option) any later version.  *
 *                                                                   *
 * This work 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 *
 * Library General Public License for more details.                  *
 *                                                                   *
 * You should have received a copy of the GNU Library 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.                                      *
 *                                                                   *
 * To submit a bug report, send a comment, or get the latest news on *
 * this project and other Sable Research Group projects, please      *
 * visit the web site: http://www.sable.mcgill.ca/                   *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/*
 Reference Version
 -----------------
 This is the latest official version on which this file is based.
 The reference version is: $SableUtilVersion: 1.11 $

 Change History
 --------------
 A) Notes:

 Please use the following template.  Most recent changes should
 appear at the top of the list.

 - Modified on [date (March 1, 1900)] by [name]. [(*) if appropriate]
   [description of modification].

 Any Modification flagged with "(*)" was done as a project of the
 Sable Research Group, School of Computer Science,
 McGill University, Canada (http://www.sable.mcgill.ca/).

 You should add your copyright, using the following template, at
 the top of this file, along with other copyrights.

 *                                                                   *
 * Modifications by [name] are                                       *
 * Copyright (C) [year(s)] [your name (or company)].  All rights     *
 * reserved.                                                         *
 *                                                                   *

 B) Changes:

 - Modified on June 7, 1998 by Etienne Gagnon (gagnon@sable.mcgill.ca). (*)
   Changed the license.
*/

import ca.mcgill.sable.util.Map.Entry;

public abstract class AbstractMap implements Map
{
    private Collection values;
    private Set keys;

    private class ValueCollection extends AbstractCollection
    {
        public int size()
        {
            return entries().size();
        }

        public Iterator iterator()
        {
            return new ValueIterator();
        }
    }

    private class ValueIterator implements Iterator
    {
        private Iterator iterator = entries().iterator();

        public boolean hasNext()
        {
            return iterator.hasNext();
        }

        public Object next()
        {
            return ((Entry) iterator.next()).getValue();
        }

        public void remove()
        {
            iterator.remove();
        }
    }

    private class KeySet extends AbstractSet
    {
        public int size()
        {
            return entries().size();
        }

        public Iterator iterator()
        {
            return new KeyIterator();
        }
    }

    private class KeyIterator implements Iterator
    {
        private Iterator iterator = entries().iterator();

        public boolean hasNext()
        {
            return iterator.hasNext();
        }

        public Object next()
        {
            return ((Entry) iterator.next()).getKey();
        }

        public void remove()
        {
            iterator.remove();
        }
    }

    public static abstract class AbstractEntry implements Entry
    {
        public boolean equals(Object o)
        {
            if(o == this)
            {
                return true;
            }

            if(!(o instanceof Entry))
            {
                return false;
            }

            Entry e = (Entry) o;
            Object k = getKey();
            Object v = getValue();

            if((k == null ? e.getKey() == null : k.equals(e.getKey())) &&
                (v == null ? e.getValue() == null : v.equals(e.getValue())))
            {
                return true;
            }

            return false;
        }

        public int hashCode()
        {
            Object k = getKey();
            Object v = getValue();

            return (k == null ? 0 : k.hashCode()) ^
                (v == null ? 0 : v.hashCode());
        }
    }
    public void clear()
    {
        entries().clear();
    }
    public boolean containsKey(Object key)
    {
        for(Iterator i = entries().iterator(); i.hasNext();)
        {
            Object k = ((Entry) i.next()).getKey();

            if(key==null ? k==null : key.equals(k))
            {
                return true;
            }
        }

        return false;
    }
    public boolean containsValue(Object value)
    {
        for(Iterator i = entries().iterator(); i.hasNext();)
        {
            Object v = ((Entry) i.next()).getValue();

            if(value==null ? v==null : value.equals(v))
            {
                return true;
            }
        }

        return false;
    }
    public boolean equals(Object o)
    {
        if(o == this)
        {
            return true;
        }

        if(!(o instanceof Map))
        {
            return false;
        }

        Map m = (Map) o;

        if(m.size() != size())
        {
            return false;
        }

        for(Iterator i = entries().iterator(); i.hasNext();)
        {
            Entry e = (Entry) i.next();
            Object k = e.getKey();

            if(!m.containsKey(k))
            {
                return false;
            }

            Object v = e.getValue();

            if(!(v==null ? m.get(k)==null : v.equals(m.get(k))))
            {
                return false;
            }
        }

        return true;
    }
    public Object get(Object key)
    {
        for(Iterator i = entries().iterator(); i.hasNext();)
        {
            Entry e = (Entry) i.next();

            if(key==null ? e.getKey()==null : key.equals(e.getKey()))
            {
                return e.getValue();
            }
        }

        return null;
    }
    public int hashCode()
    {
        int hashCode = 0;

        for(Iterator i = entries().iterator(); i.hasNext();)
        {
            hashCode += i.next().hashCode();
        }

        return hashCode;
    }
    public boolean isEmpty()
    {
        return size() == 0;
    }
    public Set keySet()
    {
        if(keys == null)
        {
            keys = new KeySet();
        }

        return keys;
    }
    public Object put(Object key, Object value)
    {
        throw new UnsupportedOperationException();
    }
    public void putAll(Map t)
    {
        for(Iterator i = t.entries().iterator(); i.hasNext();)
        {
            Entry e = (Entry) i.next();

            put(e.getKey(), e.getValue());
        }
    }
    public Object remove(Object key)
    {
        for(Iterator i = entries().iterator(); i.hasNext();)
        {
            Entry e = (Entry) i.next();

            if(key==null ? e.getKey()==null : key.equals(e.getKey()))
            {
                Object v = e.getValue();
                i.remove();
                return v;
            }
        }

        return null;
    }
    public int size()
    {
        return entries().size();
    }
    public String toString()
    {
        StringBuffer s = new StringBuffer();
        boolean first = true;

        s.append("{");
        for(Iterator i = entries().iterator(); i.hasNext();)
        {
            Entry e = (Entry) i.next();

            if(!first)
            {
                s.append(",");
            }
            else
            {
                first = false;
            }

            s.append("(");
            s.append(e.getKey());
            s.append(",");
            s.append(e.getValue());
            s.append(")");
        }
        s.append("}");

        return s.toString();
    }
    public Collection values()
    {
        if(values == null)
        {
            values = new ValueCollection();
        }

        return values;
    }
}

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