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/*
 * FindBugs - Find Bugs in Java programs
 * Copyright (C) 2003-2007 University of Maryland
 *
 * 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 edu.umd.cs.findbugs.util;

import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;

/**
 * @author William Pugh
 */
public class DualKeyHashMap {
    Map> map = new HashMap<>();

    public V get(K1 k1, K2 k2) {
        Map m = map.get(k1);
        if (m == null) {
            return null;
        }
        return m.get(k2);
    }

    public boolean containsKey(K1 k1, K2 k2) {
        Map m = map.get(k1);
        if (m == null) {
            return false;
        }
        return m.containsKey(k2);
    }

    public Map get(K1 k1) {
        Map m = map.get(k1);
        if (m == null) {
            return Collections.emptyMap();
        }
        return m;
    }

    public Set keySet() {
        return map.keySet();
    }

    public V put(K1 k1, K2 k2, V v) {
        Map m = map.get(k1);
        if (m == null) {
            m = Collections.singletonMap(k2, v);
            map.put(k1, m);
            return null;
        } else if (m instanceof HashMap) {
            return m.put(k2, v);
        } else {
            m = Util.makeSmallHashMap(m);
            map.put(k1, m);
            return m.put(k2, v);

        }

    }

}