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// to you under the Apache License, Version 2.0 (the
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//
//   http://www.apache.org/licenses/LICENSE-2.0
//
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package org.apache.impala.analysis;

import org.apache.impala.authorization.Privilege;
import org.apache.impala.catalog.FeKuduTable;
import org.apache.impala.catalog.FeTable;
import org.apache.impala.common.AnalysisException;
import org.apache.impala.thrift.TAlterTableDropPartitionParams;
import org.apache.impala.thrift.TAlterTableParams;
import org.apache.impala.thrift.TAlterTableType;
import com.google.common.base.Preconditions;

/**
 * Represents an ALTER TABLE DROP PARTITION statement.
 */
public class AlterTableDropPartitionStmt extends AlterTableStmt {
  private final boolean ifExists_;
  private final PartitionSet partitionSet_;

  // Setting this value causes dropped partition(s) to be permanently
  // deleted. For example, for HDFS tables it skips the trash mechanism
  private final boolean purgePartition_;

  public AlterTableDropPartitionStmt(TableName tableName,
      PartitionSet partitionSet, boolean ifExists, boolean purgePartition) {
    super(tableName);
    Preconditions.checkNotNull(partitionSet);
    partitionSet_ = partitionSet;
    partitionSet_.setTableName(tableName);
    ifExists_ = ifExists;
    purgePartition_ = purgePartition;
  }

  public boolean getIfNotExists() { return ifExists_; }

  @Override
  public String toSql(ToSqlOptions options) {
    StringBuilder sb = new StringBuilder("ALTER TABLE " + getTbl());
    sb.append(" DROP ");
    if (ifExists_) sb.append("IF EXISTS ");
    sb.append(partitionSet_.toSql(options));
    if (purgePartition_) sb.append(" PURGE");
    return sb.toString();
  }

  @Override
  public TAlterTableParams toThrift() {
    TAlterTableParams params = super.toThrift();
    params.setAlter_type(TAlterTableType.DROP_PARTITION);
    TAlterTableDropPartitionParams addPartParams = new TAlterTableDropPartitionParams();
    addPartParams.setPartition_set(partitionSet_.toThrift());
    addPartParams.setIf_exists(!partitionSet_.getPartitionShouldExist());
    addPartParams.setPurge(purgePartition_);
    params.setDrop_partition_params(addPartParams);
    return params;
  }

  @Override
  public void analyze(Analyzer analyzer) throws AnalysisException {
    super.analyze(analyzer);
    FeTable table = getTargetTable();
    if (table instanceof FeKuduTable) {
      throw new AnalysisException("ALTER TABLE DROP PARTITION is not supported for " +
          "Kudu tables: " + partitionSet_.toSql());
    }
    if (!ifExists_) partitionSet_.setPartitionShouldExist();
    partitionSet_.setPrivilegeRequirement(Privilege.ALTER);
    partitionSet_.analyze(analyzer);
  }
}