com.querydsl.sql.postgresql.AbstractPostgreSQLQuery Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of querydsl-sql Show documentation
SQL support for Querydsl
There is a newer version: 6.9
/*
 * 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 com.querydsl.core.QueryFlag;
import com.querydsl.core.QueryFlag.Position;
import com.querydsl.core.QueryMetadata;
import com.querydsl.core.types.Expression;
import com.querydsl.core.types.ExpressionUtils;
import com.querydsl.core.types.dsl.Expressions;
import com.querydsl.sql.AbstractSQLQuery;
import com.querydsl.sql.Configuration;
import com.querydsl.sql.RelationalPath;
import com.querydsl.sql.SQLQuery;
import java.sql.Connection;
import java.util.function.Supplier;

/**
 * {@code PostgreSQLQuery} provides PostgreSQL related extensions to SQLQuery
 *
 * @param  result type
 * @param  the concrete subtype
 * @see SQLQuery
 * @author tiwe
 */
public abstract class AbstractPostgreSQLQuery>
    extends AbstractSQLQuery {
  public AbstractPostgreSQLQuery(
      Connection conn, Configuration configuration, QueryMetadata metadata) {
    super(conn, configuration, metadata);
  }

  public AbstractPostgreSQLQuery(
      Supplier connProvider, Configuration configuration, QueryMetadata metadata) {
    super(connProvider, configuration, metadata);
  }

  /**
   * FOR SHARE causes the rows retrieved by the SELECT statement to be locked as though for update.
   *
   * @return the current object
   */
  public C forShare() {
    // global forShare support was added later, delegating to super implementation
    return super.forShare();
  }

  /**
   * With NOWAIT, the statement reports an error, rather than waiting, if a selected row cannot be
   * locked immediately.
   *
   * @return the current object
   */
  public C noWait() {
    QueryFlag noWaitFlag = configuration.getTemplates().getNoWaitFlag();
    return addFlag(noWaitFlag);
  }

  /**
   * FOR UPDATE / FOR SHARE OF tables
   *
   * @param paths tables
   * @return the current object
   */
  public C 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());
  }

  /**
   * adds a DISTINCT ON clause
   *
   * @param exprs
   * @return
   */
  public C distinctOn(Expression... exprs) {
    return addFlag(
        Position.AFTER_SELECT,
        Expressions.template(
            Object.class, "distinct on({0}) ", ExpressionUtils.list(Object.class, exprs)));
  }
}