/**
* Redistribution and use of this software and associated documentation
* ("Software"), with or without modification, are permitted provided
* that the following conditions are met:
*
* 1. Redistributions of source code must retain copyright
* statements and notices. Redistributions must also contain a
* copy of this document.
*
* 2. Redistributions in binary form must reproduce the
* above copyright notice, this list of conditions and the
* following disclaimer in the documentation and/or other
* materials provided with the distribution.
*
* 3. The name "Exolab" must not be used to endorse or promote
* products derived from this Software without prior written
* permission of Intalio, Inc. For written permission,
* please contact info@exolab.org.
*
* 4. Products derived from this Software may not be called "Exolab"
* nor may "Exolab" appear in their names without prior written
* permission of Intalio, Inc. Exolab is a registered
* trademark of Intalio, Inc.
*
* 5. Due credit should be given to the Exolab Project
* (http://www.exolab.org/).
*
* THIS SOFTWARE IS PROVIDED BY INTALIO, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
* NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
* INTALIO, INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Copyright 1999 (C) Intalio, Inc. All Rights Reserved.
*/
package org.castor.cpa.persistence.sql.driver;
import java.util.Enumeration;
import java.util.Vector;
import org.exolab.castor.jdo.engine.JDBCSyntax;
import org.exolab.castor.persist.spi.PersistenceFactory;
/**
* QueryExpression for Informix 7.x.
*
* @author <a href="mailto:santiago.arriaga@catnet.com.mx">Santiago Arriaga</a>
*/
public final class InformixQueryExpression extends JDBCQueryExpression {
public InformixQueryExpression(final PersistenceFactory factory) {
super(factory);
}
public String getStatement(final boolean lock) {
StringBuffer sql = new StringBuffer();
addSelectClause(sql);
addFromClause(sql);
boolean first = addJoinClause(sql);
addWhereClause(sql, first);
addOrderByClause(sql);
addForUpdateClause(sql, lock);
return sql.toString();
}
private void addSelectClause(final StringBuffer buffer) {
buffer.append(JDBCSyntax.SELECT);
if (_distinct) {
buffer.append(JDBCSyntax.DISTINCT);
}
buffer.append(getColumnList());
}
private void addFromClause(final StringBuffer buffer) {
buffer.append(JDBCSyntax.FROM);
Enumeration<String> tables = getFromTables();
while (tables.hasMoreElements()) {
buffer.append(tables.nextElement());
if (tables.hasMoreElements()) {
buffer.append(JDBCSyntax.TABLE_SEPARATOR);
}
}
}
/**
* This method returns an enumeration of the tables that are included in
* the from clause of a join, the resulting enumeration includes the
* necessary outer join syntax if needed.
*/
private Enumeration<String> getFromTables() {
Vector<String> vector = new Vector<String>();
Vector<String> outerTables = getOuterTables();
for (Enumeration<String> enumeration = _tables.keys(); enumeration.hasMoreElements(); ) {
String tableAlias = enumeration.nextElement();
String tableName = _tables.get(tableAlias);
StringBuffer tmp;
if (outerTables.contains(tableAlias)) {
tmp = new StringBuffer("OUTER ");
} else {
tmp = new StringBuffer();
}
if (tableAlias.equals(tableName)) {
tmp.append(_factory.quoteName(tableName));
} else {
tmp.append(_factory.quoteName(tableName) + " "
+ _factory.quoteName(tableAlias));
}
vector.addElement(_factory.quoteName(tmp.toString()));
}
return vector.elements();
}
/**
* This method obtains which are the tables on which an outer join is being
* performed from the _joins collection. Just the right table in an outer
* join is needed to create the syntax of an informix outer join
*/
private Vector<String> getOuterTables() {
Vector<String> tables = new Vector<String>();
Join join = null;
for (int i = 0; i < _joins.size(); ++i) {
join = _joins.elementAt(i);
if (join._outer) {
tables.addElement(join._rightTable);
}
}
return tables;
}
private boolean addJoinClause(final StringBuffer buffer) {
boolean first = true;
for (int i = 0; i < _joins.size(); ++i) {
if (first) {
buffer.append(JDBCSyntax.WHERE);
first = false;
} else {
buffer.append(JDBCSyntax.AND);
}
addJoin(buffer, _joins.elementAt(i));
}
return first;
}
private void addJoin(final StringBuffer buffer, final Join join) {
for (int j = 0; j < join._leftColumns.length; ++j) {
if (j > 0) {
buffer.append(JDBCSyntax.AND);
}
buffer.append(quoteTableAndColumn(join._leftTable, join._leftColumns[j]));
buffer.append(OP_EQUALS);
buffer.append(quoteTableAndColumn(join._rightTable, join._rightColumns[j]));
}
}
private String quoteTableAndColumn(final String table, final String column) {
return _factory.quoteName
(table + JDBCSyntax.TABLE_COLUMN_SEPARATOR + column);
}
private void addOrderByClause(final StringBuffer buffer) {
if (_order != null) {
buffer.append(JDBCSyntax.ORDER_BY).append(_order);
}
}
private void addForUpdateClause(final StringBuffer buffer, final boolean lock) {
// Use FOR UPDATE to lock selected tables.
if (lock) {
buffer.append(" FOR UPDATE");
}
}
}