/*******************************************************************************
* Breakout Cave Survey Visualizer
*
* Copyright (C) 2014 James Edwards
*
* jedwards8 at fastmail dot fm
*
* 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., 51
* Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*******************************************************************************/
package org.andork.func;
import java.util.IdentityHashMap;
/**
* A {@link Bimapper} whose {@link #map(Object)} and {@link #unmap(Object)}
* methods will return the same values for the same parameters, even if the
* wrapped {@link Bimapper} returns different (but equal) values for the same
* parameters.
*
* @author andy.edwards
*/
public class IdentityHashMapBimapper<I, O> extends IdentityHashMapMapper<I, O> implements Bimapper<I, O> {
private final Bimapper<I, O> wrapped;
private final IdentityHashMap<O, I> outToIn = new IdentityHashMap<O, I>();
public IdentityHashMapBimapper(Bimapper<I, O> wrapped) {
super(wrapped);
this.wrapped = wrapped;
}
@Override
public I unmap(O out) {
I result = outToIn.get(out);
if (result == null) {
outToIn.put(out, result = wrapped.unmap(out));
}
return result;
}
}