/*
* 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;
/**
* OPENJPA-1794
* An aggregate unary operation that can indicate whether a null value from the data store
* should be returned as null.
*/
@SuppressWarnings("serial")
public abstract class NullableAggregateUnaryOp extends UnaryOp {
public NullableAggregateUnaryOp(Val val) {
super(val);
}
public NullableAggregateUnaryOp(Val val, boolean noParen) {
super(val, noParen);
}
@Override
protected boolean nullableValue(ExpContext ctx, ExpState state) {
// If this is a simple operator (no joins involved), check compatibility to determine
// whether 'null' should be returned for the aggregate operation
if (ctx != null && ctx.store != null && (state.joins == null || state.joins.isEmpty())) {
return ctx.store.getConfiguration().getCompatibilityInstance().getReturnNullOnEmptyAggregateResult();
}
return false;
}
}