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/*
 * Copyright 2015 Agapsys Tecnologia Ltda-ME.
 *
 * 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.agapsys.jpa;

import java.util.List;
import java.util.Map;
import javax.persistence.EntityManager;

public class SelectBuilder extends AbstractQueryBuilder {
	
	public SelectBuilder(boolean distinct, Class entityClass, String alias) {
		super(distinct, entityClass, alias);
	}

	public SelectBuilder(Class entityClass, String alias) {
		super(entityClass, alias);
	}

	public SelectBuilder(String selectClause, Class entityClass, String alias) {
		super(selectClause, entityClass, alias);
	}

	public SelectBuilder(String selectClause, Class entityClass) {
		super(selectClause, entityClass);
	}
	
	
	@Override
	public SelectBuilder join(JoinType joinType, String joinField, String joinFieldAlias) {
		return (SelectBuilder) super.join(joinType, joinField, joinFieldAlias);
	}
	
	@Override
	public SelectBuilder joinFetch(String joinField) {
		return (SelectBuilder) super.joinFetch(joinField); 
	}
	
	@Override
	public SelectBuilder where(String whereClause) {
		return (SelectBuilder) super.where(whereClause);
	}

	@Override
	public SelectBuilder groupBy(String groupBy) {
		return (SelectBuilder) super.groupBy(groupBy);
	}
	
	@Override
	public SelectBuilder offset(Integer offset) {
		return (SelectBuilder) super.offset(offset);
	}

	@Override
	public SelectBuilder orderBy(String ordering) {
		return (SelectBuilder) super.orderBy(ordering);
	}

	@Override
	public SelectBuilder maxResults(Integer maxResults) {
		return (SelectBuilder) super.maxResults(maxResults);
	}
	
	@Override
	public SelectBuilder value(String key, Object value) {
		return (SelectBuilder) super.value(key, value);
	}

	@Override
	public SelectBuilder values(Map values) {
		return (SelectBuilder) super.values(values);
	}
	
	@Override
	public List select(EntityManager entityManager) {
		return (List) super.select(entityManager);
	}
	
	public T selectFirst(EntityManager entityManager) {
		Integer previousMaxResults = getMaxResults();
		
		setLocked(false); // <-- allows attribute change
		maxResults(1);		
		
		List results = (List) select(entityManager);

		maxResults(previousMaxResults);
		setLocked(true); // <-- restores locking state
		
		setLocked(true);
		
		if (results.isEmpty())
			return null;
		else
			return (T) results.get(0);
	}
	// =========================================================================
}