content: /*
   * This library is part of OpenCms -
   * the Open Source Content Management System
   *
   * Copyright (c) Alkacon Software GmbH & Co. KG (https://www.alkacon.com)
   *
   * This library 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 library 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
   * Lesser General Public License for more details.
   *
   * For further information about Alkacon Software, please see the
   * company website: https://www.alkacon.com
   *
   * For further information about OpenCms, please see the
   * project website: https://www.opencms.org
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   */
  
  package org.opencms.db;
  
  import java.util.ArrayList;
  import java.util.List;
  
  /**
   * Class for generating an SQL boolean expression.<p>
   *
   * @since 8.0.0
   */
  public class CmsSqlBooleanClause implements I_CmsQueryFragment {
  
      /** The list of operands. */
      private List<I_CmsQueryFragment> m_fragments = new ArrayList<I_CmsQueryFragment>();
  
      /** The boolean operator. */
      private String m_operator;
  
      /**
       * Creates a new boolean clause.<p>
       *
       * @param operator the boolean operator
       */
      public CmsSqlBooleanClause(String operator) {
  
          m_operator = operator;
      }
  
      /**
       * Creates a boolean "AND" expression.<p>
       *
       * @param fragments the operands of the "AND"
       *
       * @return the combined expression
       */
      public static CmsSqlBooleanClause makeAnd(I_CmsQueryFragment... fragments) {
  
          CmsSqlBooleanClause result = new CmsSqlBooleanClause("AND");
          for (I_CmsQueryFragment fragment : fragments) {
              result.addCondition(fragment);
          }
          return result;
  
      }
  
      /**
       * Creates a boolean "OR" expression.<p>
       *
       * @param fragments the operands of the "OR"
       *
       * @return the combined expressiong
       */
      public static CmsSqlBooleanClause makeOr(I_CmsQueryFragment... fragments) {
  
          CmsSqlBooleanClause result = new CmsSqlBooleanClause("OR");
          for (I_CmsQueryFragment fragment : fragments) {
              result.addCondition(fragment);
          }
          return result;
      }
  
      /**
       * Adds an operand to the boolean expression.<p>
       *
       * @param fragment the operand
       *
       * @return this object instance
       */
      public CmsSqlBooleanClause addCondition(I_CmsQueryFragment fragment) {
  
          m_fragments.add(fragment);
          return this;
      }
  
      /**
       * @see org.opencms.db.I_CmsQueryFragment#visit(org.opencms.db.CmsStatementBuilder)
       */
      public void visit(CmsStatementBuilder builder) {
  
          String connector = " " + m_operator + " ";
          if (m_fragments.size() == 0) {
              throw new IllegalStateException();
          } else if (m_fragments.size() == 1) {
              m_fragments.get(0).visit(builder);
          } else {
              builder.add("(");
              for (int i = 0; i < m_fragments.size(); i++) {
                  if (i != 0) {
                      builder.add(connector);
                  }
                  m_fragments.get(i).visit(builder);
              }
              builder.add(")");
          }
      }
  
  }
  