content: /**
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you 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 storm.trident.state.map;
  
  import storm.trident.state.OpaqueValue;
  import storm.trident.state.ValueUpdater;
  
  import java.util.ArrayList;
  import java.util.List;
  
  
  public class OpaqueMap<T> implements MapState<T> {
      public static <T> MapState<T> build(IBackingMap<OpaqueValue> backing) {
          return new OpaqueMap<T>(backing);
      }
      
      CachedBatchReadsMap<OpaqueValue> _backing;
      Long _currTx;
      
      protected OpaqueMap(IBackingMap<OpaqueValue> backing) {
          _backing = new CachedBatchReadsMap(backing);
      }
      
      @Override
      public List<T> multiGet(List<List<Object>> keys) {
          List<CachedBatchReadsMap.RetVal<OpaqueValue>> curr = _backing.multiGet(keys);
          List<T> ret = new ArrayList<T>(curr.size());
          for(CachedBatchReadsMap.RetVal<OpaqueValue> retval: curr) {
              OpaqueValue val = retval.val;
              if(val!=null) {
                  if(retval.cached) {
                      ret.add((T) val.getCurr());
                  } else {
                      ret.add((T) val.get(_currTx));
                  }
              } else {
                  ret.add(null);
              }
          }
          return ret;
      }
  
      @Override
      public List<T> multiUpdate(List<List<Object>> keys, List<ValueUpdater> updaters) {
          List<CachedBatchReadsMap.RetVal<OpaqueValue>> curr = _backing.multiGet(keys);
          List<OpaqueValue> newVals = new ArrayList<OpaqueValue>(curr.size());
          List<T> ret = new ArrayList<T>();
          for(int i=0; i<curr.size(); i++) {
              CachedBatchReadsMap.RetVal<OpaqueValue> retval = curr.get(i);
              OpaqueValue<T> val = retval.val;
              ValueUpdater<T> updater = updaters.get(i);
              T prev;
              if(val==null) {
                  prev = null;
              } else {
                  if(retval.cached) {
                      prev = val.getCurr();
                  } else {
                      prev = val.get(_currTx);
                  }
              }
              T newVal = updater.update(prev);
              ret.add(newVal);
              OpaqueValue<T> newOpaqueVal;
              if(val==null) {
                  newOpaqueVal = new OpaqueValue<T>(_currTx, newVal);
              } else {
                  newOpaqueVal = val.update(_currTx, newVal);
              }
              newVals.add(newOpaqueVal);
          }
          _backing.multiPut(keys, newVals);
          return ret;
      }
  
      @Override
      public void multiPut(List<List<Object>> keys, List<T> vals) {
          List<ValueUpdater> updaters = new ArrayList<ValueUpdater>(vals.size());
          for(T val: vals) {
              updaters.add(new ReplaceUpdater<T>(val));
          }
          multiUpdate(keys, updaters);
      }
  
      @Override
      public void beginCommit(Long txid) {
          _currTx = txid;
          _backing.reset();
      }
  
      @Override
      public void commit(Long txid) {
          _currTx = null;
          _backing.reset();
      }
      
      static class ReplaceUpdater<T> implements ValueUpdater<T> {
          T _t;
          
          public ReplaceUpdater(T t) {
              _t = t;
          }
          
          @Override
          public T update(Object stored) {
              return _t;
          }        
      }    
  }
  