/**
    *
    * 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.hadoop.hbase.master.handler;
  
  import java.io.IOException;
  import java.util.List;
  
  import org.apache.hadoop.hbase.HRegionInfo;
  import org.apache.hadoop.hbase.HTableDescriptor;
  import org.apache.hadoop.hbase.Server;
  import org.apache.hadoop.hbase.TableName;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.executor.EventType;
  import org.apache.hadoop.hbase.master.HMaster;
  import org.apache.hadoop.hbase.master.MasterCoprocessorHost;
  import org.apache.hadoop.hbase.master.MasterFileSystem;
  import org.apache.hadoop.hbase.master.MasterServices;
  import org.apache.hadoop.hbase.util.Bytes;
  
  /**
   * Handles Deleting a column family from an existing table.
   */
  @InterfaceAudience.Private
  public class TableDeleteFamilyHandler extends TableEventHandler {
  
    private byte [] familyName;
  
    public TableDeleteFamilyHandler(TableName tableName, byte [] familyName,
        Server server, final MasterServices masterServices) throws IOException {
      super(EventType.C_M_DELETE_FAMILY, tableName, server, masterServices);
      this.familyName = familyName;
    }
  
    @Override
    protected void prepareWithTableLock() throws IOException {
      super.prepareWithTableLock();
      HTableDescriptor htd = getTableDescriptor();
      this.familyName = hasColumnFamily(htd, familyName);
    }
  
    @Override
    protected void handleTableOperation(List<HRegionInfo> hris) throws IOException {
      MasterCoprocessorHost cpHost = ((HMaster) this.server)
          .getMasterCoprocessorHost();
      if (cpHost != null) {
        cpHost.preDeleteColumnHandler(this.tableName, this.familyName);
      }
      // Update table descriptor
      this.masterServices.getMasterFileSystem().deleteColumn(tableName, familyName);
      // Remove the column family from the file system
      MasterFileSystem mfs = this.masterServices.getMasterFileSystem();
      for (HRegionInfo hri : hris) {
        // Delete the family directory in FS for all the regions one by one
        mfs.deleteFamilyFromFS(hri, familyName);
      }
      if (cpHost != null) {
        cpHost.postDeleteColumnHandler(this.tableName, this.familyName);
      }
    }
  
    @Override
    public String toString() {
      String name = "UnknownServerName";
      if(server != null && server.getServerName() != null) {
        name = server.getServerName().toString();
      }
      String family = "UnknownFamily";
      if(familyName != null) {
        family = Bytes.toString(familyName);
      }
      return getClass().getSimpleName() + "-" + name + "-" + getSeqid() +
          "-" + tableName + "-" + family;
    }
  }