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A collection of Java utilities.
//
// $Id$
//
// samskivert library - useful routines for java programs
// Copyright (C) 2006-2010 Michael Bayne, et al.
//
// This library is free software; you can redistribute it and/or modify it
// under the terms of the GNU Lesser General Public License as published
// by the Free Software Foundation; either version 2.1 of the License, or
// (at your option) any later version.
//
// This library 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 GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
package com.samskivert.jdbc;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import com.samskivert.util.StringUtil;
import static com.samskivert.Log.log;
/**
* A superclass to help with the shrinking subset of SQL our supported dialects can agree on,
* or when there is disagreement, implement the most standard-compliant version and let the
* dialectal sub-classes override.
*/
public abstract class BaseLiaison implements DatabaseLiaison
{
public BaseLiaison ()
{
super();
}
// from DatabaseLiaison
public boolean tableExists (Connection conn, String name) throws SQLException
{
ResultSet rs = conn.getMetaData().getTables(null, null, name, null);
while (rs.next()) {
String tname = rs.getString("TABLE_NAME");
if (name.equals(tname)) {
return true;
}
}
return false;
}
// from DatabaseLiaison
public boolean tableContainsColumn (Connection conn, String table, String column)
throws SQLException
{
ResultSet rs = conn.getMetaData().getColumns(null, null, table, column);
while (rs.next()) {
String tname = rs.getString("TABLE_NAME");
String cname = rs.getString("COLUMN_NAME");
if (tname.equals(table) && cname.equals(column)) {
return true;
}
}
return false;
}
// from DatabaseLiaison
public boolean tableContainsIndex (Connection conn, String table, String index)
throws SQLException
{
ResultSet rs = conn.getMetaData().getIndexInfo(null, null, table, false, true);
while (rs.next()) {
String tname = rs.getString("TABLE_NAME");
String iname = rs.getString("INDEX_NAME");
if (tname.equals(table) && index.equals(iname)) {
return true;
}
}
return false;
}
// from DatabaseLiaison
public boolean addIndexToTable (
Connection conn, String table, String[] columns, String ixName, boolean unique)
throws SQLException
{
if (tableContainsIndex(conn, table, ixName)) {
return false;
}
ixName = (ixName != null ? ixName : StringUtil.join(columns, "_"));
StringBuilder update = new StringBuilder("CREATE ");
if (unique) {
update.append("UNIQUE ");
}
update.append("INDEX ").append(indexSQL(ixName)).append(" ON ").
append(tableSQL(table)).append(" (");
for (int ii = 0; ii < columns.length; ii ++) {
if (ii > 0) {
update.append(", ");
}
update.append(columnSQL(columns[ii]));
}
update.append(")");
executeQuery(conn, update.toString());
log.info("Database index '" + ixName + "' added to table '" + table + "'");
return true;
}
// from DatabaseLiaison
public void addPrimaryKey (Connection conn, String table, String[] columns)
throws SQLException
{
StringBuilder fields = new StringBuilder("(");
for (int ii = 0; ii < columns.length; ii ++) {
if (ii > 0) {
fields.append(", ");
}
fields.append(columnSQL(columns[ii]));
}
fields.append(")");
String update = "ALTER TABLE " + tableSQL(table) + " ADD PRIMARY KEY " + fields.toString();
executeQuery(conn, update);
log.info("Primary key " + fields + " added to table '" + table + "'");
}
// from DatabaseLiaison
public void dropIndex (Connection conn, String table, String index) throws SQLException
{
executeQuery(conn, "DROP INDEX " + columnSQL(index));
}
// from DatabaseLiaison
public void dropPrimaryKey (Connection conn, String table, String pkName)
throws SQLException
{
executeQuery(conn, "ALTER TABLE " + tableSQL(table) +
" DROP CONSTRAINT " + columnSQL(pkName));
}
// from DatabaseLiaison
public boolean addColumn (
Connection conn, String table, String column, String definition, boolean check)
throws SQLException
{
if (check && tableContainsColumn(conn, table, column)) {
return false;
}
executeQuery(conn, "ALTER TABLE " + tableSQL(table) + " ADD COLUMN " +
columnSQL(column) + " " + definition);
log.info("Database column '" + column + "' added to table '" + table + "'.");
return true;
}
// from DatabaseLiaison
public boolean addColumn (Connection conn, String table, String column,
ColumnDefinition newColumnDef, boolean check)
throws SQLException
{
if (check && tableContainsColumn(conn, table, column)) {
return false;
}
executeQuery(conn, "ALTER TABLE " + tableSQL(table) + " ADD COLUMN " +
columnSQL(column) + " " + expandDefinition(newColumnDef));
log.info("Database column '" + column + "' added to table '" + table + "'.");
return true;
}
// from DatabaseLiaison
public boolean changeColumn (Connection conn, String table, String column, String type,
Boolean nullable, Boolean unique, String defaultValue)
throws SQLException
{
String defStr = expandDefinition(
type, nullable != null ? nullable : false, unique != null ? unique : false,
defaultValue);
executeQuery(conn, "ALTER TABLE " + tableSQL(table) + " CHANGE " +
columnSQL(column) + " " + columnSQL(column) + " " + defStr);
log.info("Database column '" + column + "' of table '" + table + "' modified to have " +
"definition '" + defStr + "'.");
return true;
}
// from DatabaseLiaison
public boolean renameColumn (Connection conn, String table, String from, String to,
ColumnDefinition newColumnDef)
throws SQLException
{
executeQuery(conn, "ALTER TABLE " + tableSQL(table) + " RENAME COLUMN " +
columnSQL(from) + " TO " + columnSQL(to));
log.info("Renamed column '" + from + "' on table '" + table + "' to '" + to + "'");
return true;
}
// from DatabaseLiaison
public boolean dropColumn (Connection conn, String table, String column) throws SQLException
{
if (!tableContainsColumn(conn, table, column)) {
return false;
}
executeQuery(conn, "ALTER TABLE " + tableSQL(table) + " DROP COLUMN " + columnSQL(column));
log.info("Database column '" + column + "' removed from table '" + table + "'.");
return true;
}
// from DatabaseLiaison
public boolean createTableIfMissing (
Connection conn, String table, String[] columns, ColumnDefinition[] definitions,
String[][] uniqueConstraintColumns, String[] primaryKeyColumns)
throws SQLException
{
if (tableExists(conn, table)) {
return false;
}
if (columns.length != definitions.length) {
throw new IllegalArgumentException("Column name and definition number mismatch");
}
StringBuilder builder =
new StringBuilder("CREATE TABLE ").append(tableSQL(table)).append(" (");
for (int ii = 0; ii < columns.length; ii ++) {
if (ii > 0) {
builder.append(", ");
}
builder.append(columnSQL(columns[ii])).append(" ");
builder.append(expandDefinition(definitions[ii]));
}
if (uniqueConstraintColumns != null && uniqueConstraintColumns.length > 0) {
for (String[] uCols : uniqueConstraintColumns) {
builder.append(", UNIQUE (");
for (int ii = 0; ii < uCols.length; ii ++) {
if (ii > 0) {
builder.append(", ");
}
builder.append(columnSQL(uCols[ii]));
}
builder.append(")");
}
}
if (primaryKeyColumns != null && primaryKeyColumns.length > 0) {
builder.append(", PRIMARY KEY (");
for (int ii = 0; ii < primaryKeyColumns.length; ii ++) {
if (ii > 0) {
builder.append(", ");
}
builder.append(columnSQL(primaryKeyColumns[ii]));
}
builder.append(")");
}
builder.append(")");
executeQuery(conn, builder.toString());
log.info("Database table '" + table + "' created.");
return true;
}
public boolean dropTable (Connection conn, String name)
throws SQLException
{
if (!tableExists(conn, name)) {
return false;
}
executeQuery(conn, "DROP TABLE " + tableSQL(name));
log.info("Table '" + name + "' dropped.");
return true;
}
/**
* Create an SQL string that summarizes a column definition in that format generally
* accepted in table creation and column addition statements, e.g.
* INTEGER UNIQUE NOT NULL DEFAULT 100
*/
public String expandDefinition (ColumnDefinition def)
{
return expandDefinition(def.type, def.nullable, def.unique, def.defaultValue);
}
protected int executeQuery (Connection conn, String query)
throws SQLException
{
Statement stmt = conn.createStatement();
try {
return stmt.executeUpdate(query);
} finally {
JDBCUtil.close(stmt);
}
}
protected String expandDefinition (
String type, boolean nullable, boolean unique, String defaultValue)
{
StringBuilder builder = new StringBuilder(type);
if (!nullable) {
builder.append(" NOT NULL");
}
if (unique) {
builder.append(" UNIQUE");
}
// append the default value if one was specified
if (defaultValue != null) {
builder.append(" DEFAULT ").append(defaultValue);
}
return builder.toString();
}
}