| package org.antlr.runtime.misc; |
| |
| import java.util.*; |
| |
| /** 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<Key1, Key2, Value> { |
| Map<Key1, Map<Key2, Value>> data = new LinkedHashMap<Key1, Map<Key2, Value>>(); |
| |
| public Value put(Key1 k1, Key2 k2, Value v) { |
| Map<Key2, Value> data2 = data.get(k1); |
| Value prev = null; |
| if ( data2==null ) { |
| data2 = new LinkedHashMap<Key2, Value>(); |
| data.put(k1, data2); |
| } |
| else { |
| prev = data2.get(k2); |
| } |
| data2.put(k2, v); |
| return prev; |
| } |
| |
| public Value get(Key1 k1, Key2 k2) { |
| Map<Key2, Value> data2 = data.get(k1); |
| if ( data2==null ) return null; |
| return data2.get(k2); |
| } |
| |
| public Map<Key2, Value> get(Key1 k1) { return data.get(k1); } |
| |
| /** Get all values associated with primary key */ |
| public Collection<Value> values(Key1 k1) { |
| Map<Key2, Value> data2 = data.get(k1); |
| if ( data2==null ) return null; |
| return data2.values(); |
| } |
| |
| /** get all primary keys */ |
| public Set<Key1> keySet() { |
| return data.keySet(); |
| } |
| |
| /** get all secondary keys associated with a primary key */ |
| public Set<Key2> keySet(Key1 k1) { |
| Map<Key2, Value> data2 = data.get(k1); |
| if ( data2==null ) return null; |
| return data2.keySet(); |
| } |
| |
| public Collection<Value> values() { |
| Set<Value> s = new HashSet<Value>(); |
| for (Map<Key2, Value> k2 : data.values()) { |
| for (Value v : k2.values()) { |
| s.add(v); |
| } |
| } |
| return s; |
| } |
| } |