//
// $Id: StreamableHashMap.java,v 1.3 2003/05/28 01:18:41 mdb Exp $

package com.threerings.util;

import java.io.IOException;
import java.util.Iterator;
import java.util.Map;
import java.util.HashMap;

import com.threerings.io.ObjectInputStream;
import com.threerings.io.ObjectOutputStream;
import com.threerings.io.Streamable;

/**
 * A {@link HashMap} extension that can be streamed. The keys and values
 * in the map must also be of streamable types.
 *
 * @see Streamable
 */
public class StreamableHashMap extends HashMap
    implements Streamable
{
    /**
     * Constructs an empty hash map with the specified number of hash
     * buckets.
     */
    public StreamableHashMap (int buckets, float loadFactor)
    {
        super(buckets, loadFactor);
    }

    /**
     * Constructs an empty hash map with the default number of hash
     * buckets.
     */
    public StreamableHashMap ()
    {
        super();
    }

    /**
     * Writes our custom streamable fields.
     */
    public void writeObject (ObjectOutputStream out)
        throws IOException
    {
        int ecount = size();
        out.writeInt(ecount);
        for (Iterator iter = entrySet().iterator(); iter.hasNext(); ) {
            Map.Entry entry = (Map.Entry) iter.next();
            out.writeObject(entry.getKey());
            out.writeObject(entry.getValue());
        }
    }

    /**
     * Reads our custom streamable fields.
     */
    public void readObject (ObjectInputStream in)
        throws IOException, ClassNotFoundException
    {
        int ecount = in.readInt();
        for (int ii = 0; ii < ecount; ii++) {
            put(in.readObject(), in.readObject());
        }
    }
}
