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JDBC driver for MariaDB and MySQL
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// SPDX-License-Identifier: LGPL-2.1-or-later
// Copyright (c) 2012-2014 Monty Program Ab
// Copyright (c) 2015-2024 MariaDB Corporation Ab
package org.mariadb.jdbc.client.result;
import java.sql.SQLException;
import java.sql.Types;
import org.mariadb.jdbc.Configuration;
import org.mariadb.jdbc.client.Column;
import org.mariadb.jdbc.client.ColumnDecoder;
import org.mariadb.jdbc.export.ExceptionFactory;
import org.mariadb.jdbc.util.constants.CatalogTerm;
import org.mariadb.jdbc.util.constants.ColumnFlags;
/** Result-set metadata */
public class ResultSetMetaData implements java.sql.ResultSetMetaData {
private final ExceptionFactory exceptionFactory;
private final ColumnDecoder[] fieldPackets;
private final Configuration conf;
private final boolean forceAlias;
/**
* Constructor.
*
* @param exceptionFactory default exception handler
* @param fieldPackets column informations
* @param conf connection options
* @param forceAlias force table and column name alias as original data
*/
public ResultSetMetaData(
final ExceptionFactory exceptionFactory,
final ColumnDecoder[] fieldPackets,
final Configuration conf,
final boolean forceAlias) {
this.exceptionFactory = exceptionFactory;
this.fieldPackets = fieldPackets;
this.conf = conf;
this.forceAlias = forceAlias;
}
/**
* Returns the number of columns in this ResultSet object.
*
* @return the number of columns
*/
public int getColumnCount() {
return fieldPackets.length;
}
/**
* Indicates whether the designated column is automatically numbered.
*
* @param column the first column is 1, the second is 2, ...
* @return true if so; false otherwise
* @throws SQLException if a database access error occurs
*/
public boolean isAutoIncrement(final int column) throws SQLException {
return (getColumn(column).getFlags() & ColumnFlags.AUTO_INCREMENT) != 0;
}
/**
* Indicates whether a column's case matters.
*
* @param column the first column is 1, the second is 2, ...
* @return true if so; false otherwise
*/
public boolean isCaseSensitive(final int column) {
return true;
}
/**
* Indicates whether the designated column can be used in a where clause.
*
* @param column the first column is 1, the second is 2, ...
* @return true if so; false otherwise
*/
public boolean isSearchable(final int column) {
return true;
}
/**
* Indicates whether the designated column is a cash value.
*
* @param column the first column is 1, the second is 2, ...
* @return true if so; false otherwise
*/
public boolean isCurrency(final int column) {
return false;
}
/**
* Indicates the nullability of values in the designated column.
*
* @param column the first column is 1, the second is 2, ...
* @return the nullability status of the given column; one of columnNoNulls,
* columnNullable or columnNullableUnknown
* @throws SQLException if a database access error occurs
*/
public int isNullable(final int column) throws SQLException {
if ((getColumn(column).getFlags() & ColumnFlags.NOT_NULL) == 0) {
return java.sql.ResultSetMetaData.columnNullable;
} else {
return java.sql.ResultSetMetaData.columnNoNulls;
}
}
/**
* Indicates whether values in the designated column are signed numbers.
*
* @param column the first column is 1, the second is 2, ...
* @return true if so; false otherwise
* @throws SQLException if a database access error occurs
*/
public boolean isSigned(int column) throws SQLException {
return getColumn(column).isSigned();
}
/**
* Indicates the designated column's normal maximum width in characters.
*
* @param column the first column is 1, the second is 2, ...
* @return the normal maximum number of characters allowed as the width of the designated column
* @throws SQLException if a database access error occurs
*/
public int getColumnDisplaySize(final int column) throws SQLException {
return getColumn(column).getDisplaySize();
}
/**
* Gets the designated column's suggested title for use in printouts and displays. The suggested
* title is usually specified by the SQL AS clause. If an SQL AS is not
* specified, the value returned from getColumnLabel will be the same as the value
* returned by the getColumnName method.
*
* @param column the first column is 1, the second is 2, ...
* @return the suggested column title
* @throws SQLException if a database access error occurs
*/
public String getColumnLabel(final int column) throws SQLException {
return getColumn(column).getColumnAlias();
}
/**
* Get the designated column's name.
*
* @param idx the first column is 1, the second is 2, ...
* @return column name
* @throws SQLException if a database access error occurs
*/
public String getColumnName(final int idx) throws SQLException {
Column column = getColumn(idx);
String columnName = column.getColumnName();
if ("".equals(columnName) || forceAlias) {
return column.getColumnAlias();
}
return columnName;
}
/**
* Get the designated column's table's schema.
*
* @param column the first column is 1, the second is 2, ...
* @return schema name or "" if not applicable
* @throws SQLException if a database access error occurs
*/
public String getCatalogName(int column) throws SQLException {
if (conf.useCatalogTerm() == CatalogTerm.UseSchema) return getColumn(column).getCatalog();
return getColumn(column).getSchema();
}
/**
* Get the designated column's specified column size. For numeric data, this is the maximum
* precision. For character data, this is the length in characters. For datetime datatypes, this
* is the length in characters of the String representation (assuming the maximum allowed
* precision of the fractional seconds component). For binary data, this is the length in bytes.
* For the ROWID datatype, this is the length in bytes. 0 is returned for data types where the
* column size is not applicable.
*
* @param column the first column is 1, the second is 2, ...
* @return precision
* @throws SQLException if a database access error occurs
*/
public int getPrecision(final int column) throws SQLException {
return getColumn(column).getPrecision();
}
/**
* Gets the designated column's number of digits to right of the decimal point. 0 is returned for
* data types where the scale is not applicable.
*
* @param index the first column is 1, the second is 2, ...
* @return scale
* @throws SQLException if a database access error occurs
*/
public int getScale(final int index) throws SQLException {
return getColumn(index).getDecimals();
}
/**
* Gets the designated column's table name.
*
* @param column the first column is 1, the second is 2, ...
* @return table name or "" if not applicable
* @throws SQLException if a database access error occurs
*/
public String getTableName(final int column) throws SQLException {
if (forceAlias) {
return getColumn(column).getTableAlias();
}
if (conf.blankTableNameMeta()) {
return "";
}
return getColumn(column).getTable();
}
public String getSchemaName(int column) throws SQLException {
if (conf.useCatalogTerm() == CatalogTerm.UseSchema) return getColumn(column).getSchema();
return "";
}
/**
* Retrieves the designated column's SQL type.
*
* @param column the first column is 1, the second is 2, ...
* @return SQL type from java.sql.Types
* @throws SQLException if a database access error occurs
* @see Types
*/
public int getColumnType(final int column) throws SQLException {
return getColumn(column).getColumnType(conf);
}
/**
* Retrieves the designated column's database-specific type name.
*
* @param index the first column is 1, the second is 2, ...
* @return type name used by the database. If the column type is a user-defined type, then a
* fully-qualified type name is returned.
* @throws SQLException if a database access error occurs
*/
public String getColumnTypeName(final int index) throws SQLException {
return getColumn(index).getColumnTypeName(conf);
}
/**
* Indicates whether the designated column is definitely not writable.
*
* @param column the first column is 1, the second is 2, ...
* @return true if so; false otherwise
* @throws SQLException if a database access error occurs or in case of wrong index
*/
public boolean isReadOnly(final int column) throws SQLException {
Column ci = getColumn(column);
return ci.getColumnName().isEmpty();
}
/**
* Indicates whether it is possible for writing on the designated column to succeed.
*
* @param column the first column is 1, the second is 2, ...
* @return true if so; false otherwise
* @throws SQLException if a database access error occurs or in case of wrong index
*/
public boolean isWritable(final int column) throws SQLException {
return !isReadOnly(column);
}
/**
* Indicates whether writing on the designated column will definitely succeed.
*
* @param column the first column is 1, the second is 2, ...
* @return true if so; false otherwise
* @throws SQLException if a database access error occurs or in case of wrong index
*/
public boolean isDefinitelyWritable(final int column) throws SQLException {
return !isReadOnly(column);
}
/**
* Returns the fully-qualified name of the Java class whose instances are manufactured if the
* method ResultSet.getObject is called to retrieve a value from the column.
* ResultSet.getObject may return a subclass of the class returned by this method.
*
* @param column the first column is 1, the second is 2, ...
* @return the fully-qualified name of the class in the Java programming language that would be
* used by the method ResultSet.getObject to retrieve the value in the specified
* column. This is the class name used for custom mapping.
* @throws SQLException if a database access error occurs
*/
public String getColumnClassName(int column) throws SQLException {
return getColumn(column).defaultClassname(conf);
}
private ColumnDecoder getColumn(int column) throws SQLException {
if (column >= 1 && column <= fieldPackets.length) {
return fieldPackets[column - 1];
}
throw exceptionFactory.create(String.format("wrong column index %s", column));
}
/**
* Returns an object that implements the given interface to allow access to non-standard methods,
* or standard methods not exposed by the proxy.
* If the receiver implements the interface then the result is the receiver or a proxy for the
* receiver. If the receiver is a wrapper and the wrapped object implements the interface then the
* result is the wrapped object or a proxy for the wrapped object. Otherwise, return the result of
* calling unwrap recursively on the wrapped object or a proxy for that result. If
* the receiver is not a wrapper and does not implement the interface, then an SQLException
* is thrown.
*
* @param iface A Class defining an interface that the result must implement.
* @return an object that implements the interface. Maybe a proxy for the actual implementing
* object.
* @throws SQLException If no object found that implements the interface
*/
public T unwrap(final Class iface) throws SQLException {
if (isWrapperFor(iface)) {
return iface.cast(this);
}
throw new SQLException("The receiver is not a wrapper for " + iface.getName());
}
/**
* Returns true if this either implements the interface argument or is directly or indirectly a
* wrapper for an object that does. Returns false otherwise. If this implements the interface then
* return true, else if this is a wrapper then return the result of recursively calling
* isWrapperFor on the wrapped object. If this does not implement the interface and is not
* a wrapper, return false. This method should be implemented as a low-cost operation compared to
* unwrap so that callers can use this method to avoid expensive unwrap
* calls that may fail. If this method returns true then calling unwrap with the same
* argument should succeed.
*
* @param iface a Class defining an interface.
* @return true if this implements the interface or directly or indirectly wraps an object that
* does.
*/
public boolean isWrapperFor(final Class iface) {
return iface.isInstance(this);
}
}