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/*
* [The "BSD license"]
* Copyright (c) 2012 Terence Parr
* Copyright (c) 2012 Sam Harwell
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.antlr.v4.runtime.misc;
import java.util.Collection;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Set;
/** Sometimes we need to map a key to a value but key is two pieces of data.
* This nested hash table saves creating a single key each time we access
* map; avoids mem creation.
*/
public class DoubleKeyMap {
Map> data = new LinkedHashMap>();
public Value put(Key1 k1, Key2 k2, Value v) {
Map data2 = data.get(k1);
Value prev = null;
if ( data2==null ) {
data2 = new LinkedHashMap();
data.put(k1, data2);
}
else {
prev = data2.get(k2);
}
data2.put(k2, v);
return prev;
}
public Value get(Key1 k1, Key2 k2) {
Map data2 = data.get(k1);
if ( data2==null ) return null;
return data2.get(k2);
}
public Map get(Key1 k1) { return data.get(k1); }
/** Get all values associated with primary key */
public Collection values(Key1 k1) {
Map data2 = data.get(k1);
if ( data2==null ) return null;
return data2.values();
}
/** get all primary keys */
public Set keySet() {
return data.keySet();
}
/** get all secondary keys associated with a primary key */
public Set keySet(Key1 k1) {
Map data2 = data.get(k1);
if ( data2==null ) return null;
return data2.keySet();
}
}