content: /**
   * Copyright 2010 The Apache Software Foundation
   *
   * 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 com.alibaba.wasp.fserver.redo;
  
  import com.alibaba.wasp.EntityGroupInfo;
  import com.alibaba.wasp.plan.action.Primary;
  import org.apache.hadoop.conf.Configuration;
  
  import java.io.Closeable;
  import java.io.IOException;
  
  public abstract class Redo implements Closeable {
  
    protected final EntityGroupInfo egi;
  
    protected final Configuration conf;
  
    /**
     * Default constructor.
     * 
     * @param egi
     *          entityGroupInfo
     * @param conf
     *          passed by entityGroup.
     * 
     * @throws java.io.IOException
     */
    public Redo(EntityGroupInfo egi, Configuration conf) {
      this.conf = conf;
      this.egi = egi;
    }
  
    /**
     * initlize
     *
     * @throws java.io.IOException
     */
    abstract public void initlize() throws IOException;
  
    /**
     * Append transaction.
     *
     * @param t
     * @throws java.io.IOException
     */
    abstract public void append(Primary action, Transaction t) throws IOException;
  
    /**
     * return the last commited transaction.
     *
     * @return
     * @throws java.io.IOException
     */
    abstract public WALEdit lastCommitedTransaction() throws IOException;
  
    /**
     * Return the last transaction.
     *
     * @return
     * @throws java.io.IOException
     */
    abstract public WALEdit lastUnCommitedTransaction()
        throws InterruptedException, NotInitlizedRedoException,
        RedoLogNotServingException;
  
    /**
     *
     *
     * @return
     */
    abstract public WALEdit peekLastUnCommitedTransaction() throws IOException;
  
    /**
     * Commit the transaction.
     *
     * @param t
     * @return
     * @throws java.io.IOException
     */
    abstract public boolean commit(WALEdit edit) throws IOException;
  
    /**
     * redo
     *
     * @throws java.io.IOException
     */
    abstract public void redo() throws IOException;
  
    /**
     * 
     */
    abstract public int size();
  }