org.firebirdsql.jdbc.field.FBWorkaroundStringField Maven / Gradle / Ivy
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/*
* Firebird Open Source J2ee connector - jdbc driver
*
* Distributable under LGPL license.
* You may obtain a copy of the License at http://www.gnu.org/copyleft/lgpl.html
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* LGPL License for more details.
*
* This file was created by members of the firebird development team.
* All individual contributions remain the Copyright (C) of those
* individuals. Contributors to this file are either listed here or
* can be obtained from a CVS history command.
*
* All rights reserved.
*/
package org.firebirdsql.jdbc.field;
import java.sql.DataTruncation;
import java.sql.SQLException;
import java.sql.Types;
import org.firebirdsql.gds.XSQLVAR;
/**
* Class implementing workaround for "operation was cancelled" bug in server.
* When we send some string data exceeding maximum length of the corresponding
* field causes "operation was cancelled" in remote module of the server instead
* of "arithmetic exception..." error. This makes code debugging harder, since
* error message is not very informative.
*
* However we cannot simply check length locally. Maximum allowed length in bytes
* is connected with the character set of the field as defined lengh * maximum
* number of bytes per character in that encoding. However this does not work
* for system tables which have defined length 31, character set UNICODE_FSS and
* maximum allowed length of 31 (instead of 31 * 3 = 63).
*
* Until this bug is fixed in the engine we will simply check if field belongs
* to the system table and do not throw data truncation error locally.
*
* @author Roman Rokytskyy
*/
public class FBWorkaroundStringField extends FBStringField {
private boolean trimString;
/**
* Create instance of this class for the specified field and result set.
*
* @param field instance of {@link XSQLVAR} containing field value.
* @param dataProvider data provider for this field
* @param requiredType required type.
*
* @throws SQLException if something went wrong.
*/
public FBWorkaroundStringField(XSQLVAR field, FieldDataProvider dataProvider,
int requiredType) throws SQLException
{
super(field, dataProvider, requiredType);
}
public void setTrimString(boolean trimString) {
this.trimString = trimString;
}
public void setString(String value) throws SQLException {
byte[] data = setStringForced(value);
if (value == STRING_NULL_VALUE)
return;
if (data.length > field.sqllen && !isSystemTable(field.relname)) {
// special handling for the LIKE ? queries with CHAR(1) fields
if (!(value.length() <= field.sqllen + 2 && (value.charAt(0) == '%' || value.charAt(value.length() - 1) == '%')))
throw new DataTruncation(-1, true, false, data.length, field.sqllen);
}
}
/**
* Set string value without any check of its length. This is a workaround
* for the problem described above.
*
* @param value value to set.
*
* @throws SQLException if something went wrong.
*/
public byte[] setStringForced(String value) throws SQLException {
if (value == STRING_NULL_VALUE) {
setNull();
return null;
}
byte[] data = field.encodeString(value,javaEncoding, mappingPath);
setFieldData(data);
return data;
}
/**
* Get string value of this field.
*
* @return string value of this filed or null if the value is
* NULL.
*/
public String getString() throws SQLException {
String result = super.getString();
if (result == STRING_NULL_VALUE)
return STRING_NULL_VALUE;
if (isType(field, Types.VARCHAR))
return result;
// fix incorrect padding done by the database for multibyte charsets
if ((field.sqllen % bytesPerCharacter) == 0 && result.length() > possibleCharLength)
result = result.substring(0, possibleCharLength);
if (trimString)
result = result.trim();
return result;
}
/**
* List of system tables from Firebird 1.5
*/
private static final String[] SYSTEM_TABLES = new String[] {
"RDB$CHARACTER_SETS",
"RDB$CHECK_CONSTRAINTS",
"RDB$COLLATIONS",
"RDB$DATABASE",
"RDB$DEPENDENCIES",
"RDB$EXCEPTIONS",
"RDB$FIELDS",
"RDB$FIELD_DIMENSIONS",
"RDB$FILES",
"RDB$FILTERS",
"RDB$FORMATS",
"RDB$FUNCTIONS",
"RDB$FUNCTION_ARGUMENTS",
"RDB$GENERATORS",
"RDB$INDEX_SEGMENTS",
"RDB$INDICES",
"RDB$LOG_FILES",
"RDB$PAGES",
"RDB$PROCEDURES",
"RDB$PROCEDURE_PARAMETERS",
"RDB$REF_CONSTRAINTS",
"RDB$RELATIONS",
"RDB$RELATION_CONSTRAINTS",
"RDB$RELATION_FIELDS",
"RDB$ROLES",
"RDB$SECURITY_CLASSES",
"RDB$TRANSACTIONS",
"RDB$TRIGGERS",
"RDB$TRIGGER_MESSAGES",
"RDB$TYPES",
"RDB$USER_PRIVILEGES",
"RDB$VIEW_RELATIONS"
};
/**
* Check if specified table is system table. This method simply traverses
* hardcoded list of system tables and compares table names.
*
* @param tableName name of the table to check.
*
* @return true if specified table is system, otherwise
* false
*/
private boolean isSystemTable(String tableName) {
boolean result = false;
for (int i = 0; i < SYSTEM_TABLES.length; i++) {
if (SYSTEM_TABLES[i].equals(tableName)) {
result = true;
break;
}
}
return result;
}
}