/*
 * 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 org.apache.geode.internal.cache;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

import org.apache.geode.cache.DiskAccessException;
import org.apache.geode.internal.Assert;
import org.apache.geode.internal.cache.DiskEntry.RecoveredEntry;
import org.apache.geode.internal.cache.persistence.DiskRegionView;

/**
 * An implementation if DiskRegion used for offline export. After each oplog is recovered this disk
 * region passes the contents recovered from the oplog to an ExportWriter, which can export those
 * entries.
 */
public class ExportDiskRegion extends ValidatingDiskRegion {

  private Map<Object, RecoveredEntry> currentOplogEntries = new HashMap();
  private ExportWriter writer;


  public ExportDiskRegion(DiskStoreImpl ds, DiskRegionView drv, ExportWriter writer) {
    super(ds, drv);
    this.writer = writer;
  }

  @Override
  public DiskEntry initializeRecoveredEntry(Object key, RecoveredEntry re) {
    if (re.getValue() == null) {
      Assert.fail("Value should not have been null for key " + key);
    }
    currentOplogEntries.put(key, re);
    return super.initializeRecoveredEntry(key, re);
  }

  @Override
  public DiskEntry updateRecoveredEntry(Object key, RecoveredEntry re) {
    currentOplogEntries.put(key, re);
    return super.updateRecoveredEntry(key, re);
  }

  @Override
  public void destroyRecoveredEntry(Object key) {
    currentOplogEntries.remove(key);
    super.destroyRecoveredEntry(key);
  }

  @Override
  public void oplogRecovered(long oplogId) {
    try {
      writer.writeBatch(currentOplogEntries);
    } catch (IOException e) {
      throw new DiskAccessException("Error during export", e, this.getDiskStore());
    }
    currentOplogEntries.clear();
  }

  public static interface ExportWriter {
    /**
     * Write a batch of entries to the export system. The value in RecoveredEntry is will not be
     * null, so there is no need to fault in the value in the implementor
     * 
     * @throws IOException
     */
    public void writeBatch(Map<Object, RecoveredEntry> entries) throws IOException;
  }

}