org.antlr.v4.runtime.misc.DoubleKeyMap Maven / Gradle / Ivy
/*
* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
* Use of this file is governed by the BSD 3-clause license that
* can be found in the LICENSE.txt file in the project root.
*/
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();
}
}