CardinalityMap.java

package jetbrains.mps.internal.collections.runtime.impl;

/*Generated by MPS */

import java.util.HashMap;

/*package*/ class CardinalityMap<U> {
  private HashMap<U, Integer> map = new HashMap<U, Integer>();
  /*package*/ CardinalityMap() {
  }
  public int card(U u) {
    Integer c = map.get(u);
    return (c != null ? c : 0);
  }
  public int postInc(U u) {
    Integer c = map.get(u);
    map.put(u, (c != null ? c + 1 : 1));
    return (c != null ? c : 0);
  }
  public int postDec(U u) {
    Integer c = map.get(u);
    if (c != null && c > 1) {
      map.put(u, c - 1);
      return c;
    } else
    if (c != null && c > 0) {
      map.remove(u);
      return c;
    } else {
      map.remove(u);
      return 0;
    }
  }
  public void clear() {
    map.clear();
  }
}