/*
* Copyright 2003-2011 JetBrains s.r.o.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package jetbrains.mps.util;
import org.jetbrains.annotations.NotNull;
import java.util.HashMap;
import java.util.Map;
/**
* This is data structure used to store mapping from keys to counters.
* When counter becomes zero or non-zero, callback is called.
*
* @author Evgeny Gerashchenko
*/
public class CounterMap<K> {
public interface CounterMapHandler<K> {
void counterZero(@NotNull K key);
void counterNonZero(@NotNull K key);
}
private Map<K, Integer> myMap = new HashMap<K, Integer>();
private CounterMapHandler<K> myHandler;
public CounterMap(@NotNull CounterMapHandler<K> handler) {
myHandler = handler;
}
public CounterMap() {
this(new CounterMapHandler<K>() {
@Override
public void counterZero(@NotNull K key) {
}
@Override
public void counterNonZero(@NotNull K key) {
}
});
}
public void increment(K key) {
if (myMap.containsKey(key)) {
myMap.put(key, myMap.get(key) + 1);
} else {
myMap.put(key, 1);
myHandler.counterNonZero(key);
}
}
public void decrement(K key) {
if (myMap.containsKey(key)) {
if (myMap.get(key) == 1) {
myMap.remove(key);
myHandler.counterZero(key);
} else {
myMap.put(key, myMap.get(key) - 1);
}
}
}
public int get(K key) {
if (myMap.containsKey(key)) {
return myMap.get(key);
} else {
return 0;
}
}
public void zeroizeKey(K key) {
if (myMap.containsKey(key) && myMap.get(key) != 0) {
myHandler.counterZero(key);
}
myMap.remove(key);
}
public void removeKey(K key) {
if (myMap.containsKey(key)) {
myMap.remove(key);
}
}
public boolean isZero(K key) {
return get(key) == 0;
}
public void clear() {
for (K key : myMap.keySet()) {
myHandler.counterZero(key);
}
myMap.clear();
}
}