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SQL support for Querydsl
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/*
 * Copyright 2015, The Querydsl Team (http://www.querydsl.com/team)
 *
 * 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.querydsl.sql.postgresql;

import java.sql.Connection;

import com.querydsl.core.DefaultQueryMetadata;
import com.querydsl.core.QueryFlag.Position;
import com.querydsl.core.QueryMetadata;
import com.querydsl.core.Tuple;
import com.querydsl.core.types.Expression;
import com.querydsl.sql.*;

/**
 * {@code PostgreSQLQuery} provides PostgreSQL related extensions to SQLQuery
 *
 * @param  result type
 *
 * @see SQLQuery
 * @author tiwe
 */
public class PostgreSQLQuery extends AbstractSQLQuery> {

    public PostgreSQLQuery(Connection conn) {
        this(conn, new Configuration(PostgreSQLTemplates.DEFAULT), new DefaultQueryMetadata());
    }

    public PostgreSQLQuery(Connection conn, SQLTemplates templates) {
        this(conn, new Configuration(templates), new DefaultQueryMetadata());
    }

    public PostgreSQLQuery(Connection conn, Configuration configuration) {
        this(conn, configuration, new DefaultQueryMetadata());
    }

    public PostgreSQLQuery(Connection conn, Configuration configuration, QueryMetadata metadata) {
        super(conn, configuration, metadata);
    }

    /**
     * FOR SHARE causes the rows retrieved by the SELECT statement to be locked as though for update.
     *
     * @return the current object
     */
    public PostgreSQLQuery forShare() {
        return addFlag(SQLOps.FOR_SHARE_FLAG);
    }

    /**
     * With NOWAIT, the statement reports an error, rather than waiting, if a selected row cannot
     * be locked immediately.
     *
     * @return the current object
     */
    public PostgreSQLQuery noWait() {
        return addFlag(SQLOps.NO_WAIT_FLAG);
    }

    /**
     * FOR UPDATE / FOR SHARE OF tables
     *
     * @param paths tables
     * @return the current object
     */
    public PostgreSQLQuery of(RelationalPath... paths) {
        StringBuilder builder = new StringBuilder(" of ");
        for (RelationalPath path : paths) {
            if (builder.length() > 4) {
                builder.append(", ");
            }
            builder.append(getConfiguration().getTemplates().quoteIdentifier(path.getTableName()));
        }
        return addFlag(Position.END, builder.toString());
    }

    @Override
    public PostgreSQLQuery clone(Connection conn) {
        PostgreSQLQuery q = new PostgreSQLQuery(conn, getConfiguration(), getMetadata().clone());
        q.clone(this);
        return q;
    }

    @Override
    public  PostgreSQLQuery select(Expression expr) {
        queryMixin.setProjection(expr);
        return (PostgreSQLQuery) this;
    }

    @Override
    public PostgreSQLQuery select(Expression... exprs) {
        queryMixin.setProjection(exprs);
        return (PostgreSQLQuery) this;
    }
}