/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.openjpa.jdbc.kernel.exps;
import java.util.Map;
import org.apache.openjpa.jdbc.sql.DBDictionary;
import org.apache.openjpa.jdbc.sql.SQLBuffer;
import org.apache.openjpa.jdbc.sql.Select;
import org.apache.openjpa.kernel.exps.ExpressionVisitor;
/**
* Negates a contains expression using a subselect to make sure no
* elements meet the criteria.
*
* @author Abe White
*/
class NotContainsExpression
implements Exp {
private final Exp _exp;
/**
* Constructor. Supply the expression to negate.
*/
public NotContainsExpression(Exp exp) {
_exp = exp;
}
public ExpState initialize(Select sel, ExpContext ctx, Map contains) {
return new NotContainsExpState(contains);
}
/**
* Expression state.
*/
private static class NotContainsExpState
extends ExpState {
public final Map contains;
public NotContainsExpState(Map contains) {
this.contains = contains;
}
}
public void appendTo(Select sel, ExpContext ctx, ExpState state,
SQLBuffer buf) {
DBDictionary dict = ctx.store.getDBDictionary();
dict.assertSupport(dict.supportsSubselect, "SupportsSubselect");
Select sub = ctx.store.getSQLFactory().newSelect();
sub.setParent(sel, null);
ExpState estate = _exp.initialize(sub, ctx, ((NotContainsExpState)
state).contains);
sub.where(sub.and(null, estate.joins));
SQLBuffer where = new SQLBuffer(dict).append("(");
_exp.appendTo(sub, ctx, estate, where);
if (where.getSQL().length() > 1)
sub.where(where.append(")"));
buf.append("0 = ");
buf.appendCount(sub, ctx.fetch);
}
public void selectColumns(Select sel, ExpContext ctx, ExpState state,
boolean pks) {
ExpState estate = _exp.initialize(sel, ctx, ((NotContainsExpState)
state).contains);
_exp.selectColumns(sel, ctx, estate, true);
}
public void acceptVisit(ExpressionVisitor visitor) {
visitor.enter(this);
_exp.acceptVisit(visitor);
visitor.exit(this);
}
}