/** This is more expensive than normal. */
@Override
public void clear() {
// iterate over all keys in originalMap and set them to null in deltaMap
for (K key : originalMap.keySet()) {
deltaMap.put(key, ErasureUtils.<Collection<V>>uncheckedCast(removedValue));
}
}
@Override
public void add(K key, V value) {
Collection<V> deltaC = deltaMap.get(key);
if (deltaC == null) {
deltaC = cf.newCollection();
Collection<V> originalC = originalMap.get(key);
if (originalC != null) {
deltaC.addAll(originalC);
}
deltaMap.put(key, deltaC);
}
deltaC.add(value);
}
@Override
public Collection<V> get(Object key) {
// key could be not in original or in deltaMap
// key could be not in original but in deltaMap
// key could be in original but removed from deltaMap
// key could be in original but mapped to something else in deltaMap
Collection<V> deltaResult = deltaMap.get(key);
if (deltaResult == null) {
return originalMap.get(key);
}
if (deltaResult == removedValue) {
return cf.newEmptyCollection();
}
return deltaResult;
}
@Override
public boolean containsKey(Object key) {
// key could be not in original or in deltaMap
// key could be not in original but in deltaMap
// key could be in original but removed from deltaMap
// key could be in original but mapped to something else in deltaMap
Object value = deltaMap.get(key);
if (value == null) {
return originalMap.containsKey(key);
}
if (value == removedValue) {
return false;
}
return true;
}
@Override
public void removeMapping(K key, V value) {
Collection<V> deltaC = deltaMap.get(key);
if (deltaC == null) {
Collection<V> originalC = originalMap.get(key);
if (originalC != null && originalC.contains(value)) {
deltaC = cf.newCollection();
deltaC.addAll(originalC);
deltaMap.put(key, deltaC);
}
}
if (deltaC != null) {
deltaC.remove(value);
}
}
