package us.codecraft.webmagic.utils;
   
   /**
    * @author code4crafter@gmail.com
    */
   
   import java.util.HashMap;
   import java.util.Map;
   
  /**
   * multi-key map, some basic objects *
   *
   * @author yihua.huang
   */
  public abstract class MultiKeyMapBase {
  
      protected static final Class<? extends Map> DEFAULT_CLAZZ = HashMap.class;
      @SuppressWarnings("rawtypes")
      private Class<? extends Map> protoMapClass = DEFAULT_CLAZZ;
  
      public MultiKeyMapBase() {
      }
  
      @SuppressWarnings("rawtypes")
      public MultiKeyMapBase(Class<? extends Map> protoMapClass) {
          this.protoMapClass = protoMapClass;
      }
  
      @SuppressWarnings("unchecked")
      protected <K, V2> Map<K, V2> newMap() {
          try {
              return (Map<K, V2>) protoMapClass.newInstance();
          } catch (InstantiationException e) {
              throw new IllegalArgumentException("wrong proto type map "
                      + protoMapClass);
          } catch (IllegalAccessException e) {
              throw new IllegalArgumentException("wrong proto type map "
                      + protoMapClass);
          }
      }
  }