/* Copyright (c) 2001-2011, The HSQL Development Group
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 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.
*
* Neither the name of the HSQL Development Group nor the names of its
* contributors may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.hsqldb;
import org.hsqldb.error.
Error;
import org.hsqldb.error.
ErrorCode;
/**
* Implementation of ORDER BY operations
*
* @author Fred Toussi (fredt@users dot sourceforge.net)
* @version 2.0.1
* @since 1.9.0
*/
public class
ExpressionOrderBy extends
Expression {
private boolean
isDescending;
private boolean
isNullsLast;
ExpressionOrderBy(
Expression e) {
super(
OpTypes.
ORDER_BY);
nodes = new
Expression[
UNARY];
nodes[
LEFT] =
e;
collation =
e.
collation;
e.
collation = null;
}
/**
* Set an ORDER BY column expression DESC
*/
void
setDescending() {
isDescending = true;
}
/**
* Is an ORDER BY column expression DESC
*/
boolean
isDescending() {
return
isDescending;
}
/**
* Set an ORDER BY column NULL ordering
*/
void
setNullsLast(boolean
value) {
isNullsLast =
value;
}
/**
* Is an ORDER BY column NULL ordering
*/
boolean
isNullsLast() {
return
isNullsLast;
}
public
Object getValue(
Session session) {
return
nodes[
LEFT].
getValue(
session);
}
public void
resolveTypes(
Session session,
Expression parent) {
nodes[
LEFT].
resolveTypes(
session,
parent);
if (
nodes[
LEFT].
isUnresolvedParam()) {
throw
Error.
error(
ErrorCode.
X_42567);
}
dataType =
nodes[
LEFT].
dataType;
if (
collation != null && !
dataType.
isCharacterType()) {
throw
Error.
error(
ErrorCode.
X_2H000,
collation.
getName().
statementName);
}
}
public
String getSQL() {
StringBuffer sb = new
StringBuffer();
sb.
append(
Tokens.
T_ORDER).
append(' ').
append(
Tokens.
T_BY).
append(' ');
if (
nodes[
LEFT].
alias != null) {
sb.
append(
nodes[
LEFT].
alias.
name);
} else {
sb.
append(
nodes[
LEFT].
getSQL());
}
if (
collation != null) {
sb.
append(' ').
append(
collation.
getName().
getSchemaQualifiedStatementName());
}
if (
isDescending) {
sb.
append(' ').
append(
Tokens.
T_DESC);
}
return
sb.
toString();
}
protected
String describe(
Session session, int
blanks) {
StringBuffer sb = new
StringBuffer();
sb.
append(
getLeftNode().
describe(
session,
blanks));
if (
isDescending) {
for (int
i = 0;
i <
blanks;
i++) {
sb.
append(' ');
}
sb.
append(
Tokens.
T_DESC).
append('\n');
}
return
sb.
toString();
}
}