AbstractCharKeyMap.java

/*
 *  Primitive Collections for Java.
 *  Copyright (C) 2003  Søren Bak
 *
 *  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
 */
package com.uwyn.jhighlight.pcj.map;

import com.uwyn.jhighlight.pcj.hash.DefaultCharHashFunction;
import com.uwyn.jhighlight.pcj.map.CharKeyMap;
import com.uwyn.jhighlight.pcj.map.CharKeyMapIterator;

/**
 *  This class represents an abstract base for implementing
 *  maps from char values to objects. All operations that can be implemented
 *  using iterators
 *  are implemented as such. In most cases, this is
 *  hardly an efficient solution, and at least some of those
 *  methods should be overridden by sub-classes.
 *
 *  @author     Søren Bak
 *  @version    1.0     2003/10/1
 *  @since      1.0
 */
public abstract class AbstractCharKeyMap implements CharKeyMap
{
	
    /** Default constructor to be invoked by sub-classes. */
    protected AbstractCharKeyMap()
	{ }
	
    public void clear()
	{
        CharKeyMapIterator i = entries();
        while (i.hasNext())
		{
            i.next();
            i.remove();
        }
    }
	
    public Object remove(char key)
	{
        CharKeyMapIterator i = entries();
        while (i.hasNext())
		{
            i.next();
            if (i.getKey()==key)
			{
                Object value = i.getValue();
                i.remove();
                return value;
            }
        }
        return null;
    }
	
    public void putAll(CharKeyMap map)
	{
        CharKeyMapIterator i = map.entries();
        while (i.hasNext())
		{
            i.next();
            put(i.getKey(), i.getValue());
        }
    }
	
    public boolean containsKey(char key)
	{
        CharKeyMapIterator i = entries();
        while (i.hasNext())
		{
            i.next();
            if (i.getKey()==key)
                return true;
        }
        return false;
    }
	
    public Object get(char key)
	{
        CharKeyMapIterator i = entries();
        while (i.hasNext())
		{
            i.next();
            if (i.getKey()==key)
                return i.getValue();
        }
        return null;
    }
	
    public boolean containsValue(Object value)
	{
        CharKeyMapIterator i = entries();
        if (value==null)
		{
            while (i.hasNext())
			{
                i.next();
                if (value==null)
                    return true;
            }
        }
		else
		{
            while (i.hasNext())
			{
                i.next();
                if (value.equals(i.getValue()))
                    return true;
            }
        }
        return false;
    }
	
    @Override
    public boolean equals(Object obj)
	{
        if (!(obj instanceof CharKeyMap))
            return false;
        CharKeyMap map = (CharKeyMap)obj;
        if (size()!=map.size())
            return false;
        CharKeyMapIterator i = entries();
        while (i.hasNext())
		{
            i.next();
            char k = i.getKey();
            Object v = i.getValue();
            if (v==null)
			{
                if (map.get(k)!=null)
                    return false;
                if (!map.containsKey(k))
                    return false;
            }
			else
			{
                if (!v.equals(map.get(k)))
                    return false;
            }
        }
        return true;
    }
	
    @Override
    public int hashCode()
	{
        int h = 0;
        CharKeyMapIterator i = entries();
        while (i.hasNext())
		{
            i.next();
            h += (DefaultCharHashFunction.INSTANCE.hash(i.getKey())^i.getValue().hashCode());
        }
        return h;
    }
	
    public boolean isEmpty()
    { return size()==0; }
	
    public int size()
	{
        int size = 0;
        CharKeyMapIterator i = entries();
        while (i.hasNext())
		{
            i.next();
            size++;
        }
        return size;
    }
	
    /**
     *  Returns a string representation of this map.
     *
     *  @return     a string representation of this map.
     */
    @Override
    public String toString()
	{
        StringBuffer s = new StringBuffer();
        s.append('[');
        CharKeyMapIterator i = entries();
        while (i.hasNext())
		{
            if (s.length()>1)
                s.append(',');
            i.next();
            s.append(String.valueOf(i.getKey()));
            s.append("->");
            s.append(String.valueOf(i.getValue()));
        }
        s.append(']');
        return s.toString();
    }
	
    /**
     *  Does nothing. Sub-classes may provide an implementation to
     *  minimize memory usage, but this is not required since many
     *  implementations will always have minimal memory usage.
     */
    public void trimToSize()
    { }
	
}