Package net.sf.jsqlparser.util

Source Code of net.sf.jsqlparser.util.SelectUtils

/*
* #%L
* JSQLParser library
* %%
* Copyright (C) 2004 - 2014 JSQLParser
* %%
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation, either version 2.1 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
* GNU General Lesser Public License for more details.
*
* You should have received a copy of the GNU General Lesser Public
* License along with this program.  If not, see
* <http://www.gnu.org/licenses/lgpl-2.1.html>.
* #L%
*/
package net.sf.jsqlparser.util;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import net.sf.jsqlparser.JSQLParserException;
import net.sf.jsqlparser.expression.Expression;
import net.sf.jsqlparser.parser.CCJSqlParserUtil;
import net.sf.jsqlparser.schema.Column;
import net.sf.jsqlparser.schema.Table;
import net.sf.jsqlparser.statement.select.AllColumns;
import net.sf.jsqlparser.statement.select.Join;
import net.sf.jsqlparser.statement.select.PlainSelect;
import net.sf.jsqlparser.statement.select.Select;
import net.sf.jsqlparser.statement.select.SelectExpressionItem;
import net.sf.jsqlparser.statement.select.SelectItem;
import net.sf.jsqlparser.statement.select.SelectVisitor;
import net.sf.jsqlparser.statement.select.SetOperationList;
import net.sf.jsqlparser.statement.select.WithItem;

/**
* Utility function for select statements.
*
* @author toben
*/
public final class SelectUtils {

  private SelectUtils() {
  }
 
  /**
   * Builds select expr1, expr2 from table.
   * @param table
   * @param expr
   * @return
   */
  public static Select buildSelectFromTableAndExpressions(Table table, Expression ... expr) {
    SelectItem[] list = new SelectItem[expr.length];
    for (int i=0;i<expr.length;i++) {
      list[i]=new SelectExpressionItem(expr[i]);
    }
    return buildSelectFromTableAndSelectItems(table, list);
  }
 
  /**
   * Builds select expr1, expr2 from table.
   * @param table
   * @param expr
   * @return
   * @throws net.sf.jsqlparser.JSQLParserException
   */
  public static Select buildSelectFromTableAndExpressions(Table table, String ... expr) throws JSQLParserException {
    SelectItem[] list = new SelectItem[expr.length];
    for (int i=0;i<expr.length;i++) {
      list[i]=new SelectExpressionItem(CCJSqlParserUtil.parseExpression(expr[i]));
    }
    return buildSelectFromTableAndSelectItems(table, list);
  }
 
  public static Select buildSelectFromTableAndSelectItems(Table table, SelectItem ... selectItems) {
    Select select = new Select();
    PlainSelect body = new PlainSelect();
    body.addSelectItems(selectItems);
    body.setFromItem(table);
    select.setSelectBody(body);
    return select;
  }
 
  /**
   * Builds select * from table.
   * @param table
   * @return
   */
  public static Select buildSelectFromTable(Table table) {
    return buildSelectFromTableAndSelectItems(table, new AllColumns());
  }

  /**
   * Adds an expression to select statements. E.g. a simple column is an
   * expression.
   *
   * @param select
   * @param expr
   */
  public static void addExpression(Select select, final Expression expr) {
    select.getSelectBody().accept(new SelectVisitor() {

      @Override
      public void visit(PlainSelect plainSelect) {
        plainSelect.getSelectItems().add(new SelectExpressionItem(expr));
      }

      @Override
      public void visit(SetOperationList setOpList) {
        throw new UnsupportedOperationException("Not supported yet.");
      }

      @Override
      public void visit(WithItem withItem) {
        throw new UnsupportedOperationException("Not supported yet.");
      }
    });
  }

  /**
   * Adds a simple join to a select statement. The introduced join is returned for
   * more configuration settings on it (e.g. left join, right join).
   * @param select
   * @param table
   * @param onExpression
   * @return
   */
  public static Join addJoin(Select select, final Table table, final Expression onExpression) {
    if (select.getSelectBody() instanceof PlainSelect) {
      PlainSelect plainSelect = (PlainSelect) select.getSelectBody();
      List<Join> joins = plainSelect.getJoins();
      if (joins == null) {
        joins = new ArrayList<Join>();
        plainSelect.setJoins(joins);
      }
      Join join = new Join();
      join.setRightItem(table);
      join.setOnExpression(onExpression);
      joins.add(join);
      return join;
    }
    throw new UnsupportedOperationException("Not supported yet.");
  }
}
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