import java.util.HashMap;import java.util.Map;import java.util.concurrent.ConcurrentHashMap;import java.util.concurrent.ConcurrentMap;

 

public interface DataStore {    /**     * return a snapshot value of componentName     */    Map
     
       get(String componentName);    Object get(String componentName, String key);    void put(String componentName, String key, Object value);    void remove(String componentName, String key);}
     

 

public class SimpleDataStore implements DataStore {    // 
     <组件类名或标识,>
      <数据名, 数据值>
       >    private ConcurrentMap
       
        > data =        new ConcurrentHashMap
        
         >();    public Map
         
           get(String componentName) {        ConcurrentMap
          
            value = data.get(componentName); if(value == null) return new HashMap
           
            (); return new HashMap
            
             (value); } public Object get(String componentName, String key) { if (!data.containsKey(componentName)) { return null; } return data.get(componentName).get(key); } public void put(String componentName, String key, Object value) { Map
             
               componentData = data.get(componentName); if(null == componentData) { data.putIfAbsent(componentName, new ConcurrentHashMap
              
               ()); componentData = data.get(componentName); } componentData.put(key, value); } public void remove(String componentName, String key) { if (!data.containsKey(componentName)) { return; } data.get(componentName).remove(key); }}