JdbcColumn.java

package com.alimama.mdrill.jdbc;


import java.sql.SQLException;
import java.sql.Types;

public class JdbcColumn {
	  private final String columnName;
	  private final String tableName;
	  private final String tableCatalog;
	  private final String type;
	  private final String comment;
	  private final int ordinalPos;

	  JdbcColumn(String columnName, String tableName, String tableCatalog
	          , String type, String comment, int ordinalPos) {
	    this.columnName = columnName;
	    this.tableName = tableName;
	    this.tableCatalog = tableCatalog;
	    this.type = type;
	    this.comment = comment;
	    this.ordinalPos = ordinalPos;
	  }

	  public String getColumnName() {
	    return columnName;
	  }

	  public String getTableName() {
	    return tableName;
	  }

	  public String getTableCatalog() {
	    return tableCatalog;
	  }

	  public String getType() {
	    return type;
	  }

	  public Integer getSqlType() throws SQLException {
	    return Utils.hiveTypeToSqlType(type);
	  }

	  static int columnDisplaySize(int columnType) throws SQLException {
	    // according to hiveTypeToSqlType possible options are:
	    switch(columnType) {
	    case Types.BOOLEAN:
	      return columnPrecision(columnType);
	    case Types.VARCHAR:
	      return Integer.MAX_VALUE; // hive has no max limit for strings
	    case Types.TINYINT:
	    case Types.SMALLINT:
	    case Types.INTEGER:
	    case Types.BIGINT:
	      return columnPrecision(columnType) + 1; // allow +/-

	    // see http://download.oracle.com/javase/6/docs/api/constant-values.html#java.lang.Float.MAX_EXPONENT
	    case Types.FLOAT:
	      return 24; // e.g. -(17#).e-###
	    // see http://download.oracle.com/javase/6/docs/api/constant-values.html#java.lang.Double.MAX_EXPONENT
	    case Types.DOUBLE:
	      return 25; // e.g. -(17#).e-####
	    default:
	      throw new SQLException("Invalid column type: " + columnType);
	    }
	  }

	  static int columnPrecision(int columnType) throws SQLException {
	    // according to hiveTypeToSqlType possible options are:
	    switch(columnType) {
	    case Types.BOOLEAN:
	      return 1;
	    case Types.VARCHAR:
	      return Integer.MAX_VALUE; // hive has no max limit for strings
	    case Types.TINYINT:
	      return 3;
	    case Types.SMALLINT:
	      return 5;
	    case Types.INTEGER:
	      return 10;
	    case Types.BIGINT:
	      return 19;
	    case Types.FLOAT:
	      return 7;
	    case Types.DOUBLE:
	      return 15;
	    default:
	      throw new SQLException("Invalid column type: " + columnType);
	    }
	  }

	  static int columnScale(int columnType) throws SQLException {
	    // according to hiveTypeToSqlType possible options are:
	    switch(columnType) {
	    case Types.BOOLEAN:
	    case Types.VARCHAR:
	    case Types.TINYINT:
	    case Types.SMALLINT:
	    case Types.INTEGER:
	    case Types.BIGINT:
	      return 0;
	    case Types.FLOAT:
	      return 7;
	    case Types.DOUBLE:
	      return 15;
	    default:
	      throw new SQLException("Invalid column type: " + columnType);
	    }
	  }

	  public Integer getColumnSize() throws SQLException {
	    int precision = columnPrecision(Utils.hiveTypeToSqlType(type));

	    return precision == 0 ? null : precision;
	  }

	  public Integer getDecimalDigits() throws SQLException {
	    return columnScale(Utils.hiveTypeToSqlType(type));
	  }

	  public Integer getNumPrecRadix() {
	    if (type.equalsIgnoreCase("tinyint")) {
	      return 10;
	    } else if (type.equalsIgnoreCase("smallint")) {
	      return 10;
	    } else if (type.equalsIgnoreCase("int")) {
	      return 10;
	    } else if (type.equalsIgnoreCase("bigint")) {
	      return 10;
	    } else if (type.equalsIgnoreCase("float")) {
	      return 2;
	    } else if (type.equalsIgnoreCase("double")) {
	      return 2;
	    } else { // anything else including boolean and string is null
	      return null;
	    }
	  }

	  public String getComment() {
	    return comment;
	  }

	  public int getOrdinalPos() {
	    return ordinalPos;
	  }
}