public Map describeColumns()

in connectors/rocketmq-connect-jdbc/src/main/java/org/apache/rocketmq/connect/jdbc/dialect/GenericDatabaseDialect.java [422:519]
94 lines of code
9 McCabe index (conditional complexity)

    public Map<ColumnId, ColumnDefinition> describeColumns(
            Connection connection,
            String catalogPattern,
            String schemaPattern,
            String tablePattern,
            String columnPattern
    ) throws SQLException {
        log.debug(
                "Querying {} dialect column metadata for catalog:{} schema:{} table:{}",
                this,
                catalogPattern,
                schemaPattern,
                tablePattern);

        // Get the primary keys of the table(s) ...
        final Set<ColumnId> pkColumns = primaryKeyColumns(
                connection,
                catalogPattern,
                schemaPattern,
                tablePattern
        );
        Map<ColumnId, ColumnDefinition> results = new HashMap<>();
        try (ResultSet rs = connection.getMetaData().getColumns(
                catalogPattern,
                schemaPattern,
                tablePattern,
                columnPattern
        )) {
            final int rsColumnCount = rs.getMetaData().getColumnCount();
            while (rs.next()) {
                final String catalogName = rs.getString(1);
                final String schemaName = rs.getString(2);
                final String tableName = rs.getString(3);
                final TableId tableId = new TableId(catalogName, schemaName, tableName);
                final String columnName = rs.getString(4);
                final ColumnId columnId = new ColumnId(tableId, columnName, null);
                final int jdbcType = rs.getInt(5);
                final String typeName = rs.getString(6);
                final int precision = rs.getInt(7);
                final int scale = rs.getInt(9);
                final String typeClassName = null;
                ColumnDefinition.Nullability nullability;
                final int nullableValue = rs.getInt(11);
                switch (nullableValue) {
                    case DatabaseMetaData.columnNoNulls:
                        nullability = ColumnDefinition.Nullability.NOT_NULL;
                        break;
                    case DatabaseMetaData.columnNullable:
                        nullability = ColumnDefinition.Nullability.NULL;
                        break;
                    case DatabaseMetaData.columnNullableUnknown:
                    default:
                        nullability = ColumnDefinition.Nullability.UNKNOWN;
                        break;
                }
                Boolean autoIncremented = null;
                if (rsColumnCount >= 23) {
                    // Not all drivers include all columns ...
                    String isAutoIncremented = rs.getString(23);
                    if ("yes".equalsIgnoreCase(isAutoIncremented)) {
                        autoIncremented = Boolean.TRUE;
                    } else if ("no".equalsIgnoreCase(isAutoIncremented)) {
                        autoIncremented = Boolean.FALSE;
                    }
                }
                Boolean signed = null;
                Boolean caseSensitive = null;
                Boolean searchable = null;
                Boolean currency = null;
                Integer displaySize = null;
                boolean isPrimaryKey = pkColumns.contains(columnId);
                if (isPrimaryKey) {
                    // Some DBMSes report pks as null
                    nullability = ColumnDefinition.Nullability.NOT_NULL;
                }
                ColumnDefinition defn = columnDefinition(
                        rs,
                        columnId,
                        jdbcType,
                        typeName,
                        typeClassName,
                        nullability,
                        ColumnDefinition.Mutability.UNKNOWN,
                        precision,
                        scale,
                        signed,
                        displaySize,
                        autoIncremented,
                        caseSensitive,
                        searchable,
                        currency,
                        isPrimaryKey
                );
                results.put(columnId, defn);
            }
            return results;
        }
    }