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;
  
  import org.apache.commons.lang.builder.ToStringBuilder;
  
  public class OpaqueValue<T> {
      Long currTxid;
      T prev;
      T curr;
  
      public OpaqueValue(Long currTxid, T val, T prev) {
          this.curr = val;
          this.currTxid = currTxid;
          this.prev = prev;
      }
  
      public OpaqueValue(Long currTxid, T val) {
          this(currTxid, val, null);
      }
  
      public OpaqueValue<T> update(Long batchTxid, T newVal) {
          T prev;
          if (batchTxid == null || (this.currTxid < batchTxid)) {
              prev = this.curr;
          } else if (batchTxid.equals(this.currTxid)) {
              prev = this.prev;
          } else {
              throw new RuntimeException("Current batch (" + batchTxid + ") is behind state's batch: " + this.toString());
          }
          return new OpaqueValue<T>(batchTxid, newVal, prev);
      }
  
      public T get(Long batchTxid) {
          if (batchTxid == null || (this.currTxid < batchTxid)) {
              return curr;
          } else if (batchTxid.equals(this.currTxid)) {
              return prev;
          } else {
              throw new RuntimeException("Current batch (" + batchTxid + ") is behind state's batch: " + this.toString());
          }
      }
  
      public T getCurr() {
          return curr;
      }
  
      public Long getCurrTxid() {
          return currTxid;
      }
  
      public T getPrev() {
          return prev;
      }
  
      @Override
      public String toString() {
          return ToStringBuilder.reflectionToString(this);
      }
  }
  