/*
* Copyright 2014 - 2017 Blazebit.
*
* Licensed 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 com.blazebit.persistence.impl.builder.predicate;
import com.blazebit.persistence.impl.BuilderChainingException;
import com.blazebit.persistence.impl.predicate.PredicateBuilder;
/**
* A base class that provides functionality to start and stop builders in a manner, such that only one builder can be started at a time.
*
* @author Christian Beikov
* @author Moritz Becker
* @since 1.0
*/
public class PredicateBuilderEndedListenerImpl implements PredicateBuilderEndedListener {
private PredicateBuilder currentBuilder;
public void verifyBuilderEnded() {
if (currentBuilder != null) {
throw new BuilderChainingException("A builder was not ended properly.");
}
}
public <T extends PredicateBuilder> T startBuilder(T builder) {
if (currentBuilder != null) {
throw new BuilderChainingException("There was an attempt to start a builder but a previous builder was not ended.");
}
currentBuilder = builder;
return builder;
}
@Override
public void onBuilderEnded(PredicateBuilder builder) {
if (currentBuilder == null) {
throw new BuilderChainingException("There was an attempt to end a builder that was not started or already closed.");
}
currentBuilder = null;
}
}