/*
* Copyright 2004-2011 H2 Group. Multiple-Licensed under the H2 License,
* Version 1.0, and under the Eclipse Public License, Version 1.0
* (http://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.expression;
import org.h2.engine.Session;
import org.h2.table.ColumnResolver;
import org.h2.table.TableFilter;
import org.h2.value.Value;
import org.h2.value.ValueNull;
/**
* A NOT condition.
*/
public class ConditionNot extends Condition {
private Expression condition;
public ConditionNot(Expression condition) {
this.condition = condition;
}
public Expression getNotIfPossible(Session session) {
return condition;
}
public Value getValue(Session session) {
Value v = condition.getValue(session);
if (v == ValueNull.INSTANCE) {
return v;
}
return v.convertTo(Value.BOOLEAN).negate();
}
public void mapColumns(ColumnResolver resolver, int level) {
condition.mapColumns(resolver, level);
}
public Expression optimize(Session session) {
Expression e2 = condition.getNotIfPossible(session);
if (e2 != null) {
return e2.optimize(session);
}
Expression expr = condition.optimize(session);
if (expr.isConstant()) {
Value v = expr.getValue(session);
if (v == ValueNull.INSTANCE) {
return ValueExpression.getNull();
}
return ValueExpression.get(v.convertTo(Value.BOOLEAN).negate());
}
condition = expr;
return this;
}
public void setEvaluatable(TableFilter tableFilter, boolean b) {
condition.setEvaluatable(tableFilter, b);
}
public String getSQL() {
return "(NOT " + condition.getSQL() + ")";
}
public void updateAggregate(Session session) {
condition.updateAggregate(session);
}
public void addFilterConditions(TableFilter filter, boolean outerJoin) {
if (outerJoin) {
// can not optimize:
// select * from test t1 left join test t2 on t1.id = t2.id where
// not t2.id is not null
// to
// select * from test t1 left join test t2 on t1.id = t2.id and
// t2.id is not null
return;
}
super.addFilterConditions(filter, outerJoin);
}
public boolean isEverything(ExpressionVisitor visitor) {
return condition.isEverything(visitor);
}
public int getCost() {
return condition.getCost();
}
}