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.TransactionalValue;
  import storm.trident.state.ValueUpdater;
  
  import java.util.ArrayList;
  import java.util.List;
  
  
  public class TransactionalMap<T> implements MapState<T> {
      public static <T> MapState<T> build(IBackingMap<TransactionalValue> backing) {
          return new TransactionalMap<T>(backing);
      }
  
      CachedBatchReadsMap<TransactionalValue> _backing;
      Long _currTx;
      
      protected TransactionalMap(IBackingMap<TransactionalValue> backing) {
          _backing = new CachedBatchReadsMap(backing);
      }
      
      @Override
      public List<T> multiGet(List<List<Object>> keys) {
          List<CachedBatchReadsMap.RetVal<TransactionalValue>> vals = _backing.multiGet(keys);
          List<T> ret = new ArrayList<T>(vals.size());
          for(CachedBatchReadsMap.RetVal<TransactionalValue> retval: vals) {
              TransactionalValue v = retval.val;
              if(v!=null) {
                  ret.add((T) v.getVal());
              } else {
                  ret.add(null);
              }
          }
          return ret;
      }
  
      @Override
      public List<T> multiUpdate(List<List<Object>> keys, List<ValueUpdater> updaters) {
          List<CachedBatchReadsMap.RetVal<TransactionalValue>> curr = _backing.multiGet(keys);
          List<TransactionalValue> newVals = new ArrayList<TransactionalValue>(curr.size());
          List<List<Object>> newKeys = new ArrayList();
          List<T> ret = new ArrayList<T>();
          for(int i=0; i<curr.size(); i++) {
              CachedBatchReadsMap.RetVal<TransactionalValue> retval = curr.get(i);
              TransactionalValue<T> val = retval.val;
              ValueUpdater<T> updater = updaters.get(i);
              TransactionalValue<T> newVal;
              boolean changed = false;
              if(val==null) {
                  newVal = new TransactionalValue<T>(_currTx, updater.update(null));
                  changed = true;
              } else {
                  if(_currTx!=null && _currTx.equals(val.getTxid()) && !retval.cached) {
                      newVal = val;
                  } else {
                      newVal = new TransactionalValue<T>(_currTx, updater.update(val.getVal()));
                      changed = true;
                  }
              }
              ret.add(newVal.getVal());
              if(changed) {
                  newVals.add(newVal);
                  newKeys.add(keys.get(i));
              }
          }
          if(!newKeys.isEmpty()) {
              _backing.multiPut(newKeys, newVals);
          }
          return ret;
      }
  
      @Override
      public void multiPut(List<List<Object>> keys, List<T> vals) {
          List<TransactionalValue> newVals = new ArrayList<TransactionalValue>(vals.size());
          for(T val: vals) {
              newVals.add(new TransactionalValue<T>(_currTx, val));
          }
          _backing.multiPut(keys, newVals);
      }
  
      @Override
      public void beginCommit(Long txid) {
          _currTx = txid;
          _backing.reset();
      }
  
      @Override
      public void commit(Long txid) {
          _currTx = null;
          _backing.reset();
      }
  }
  