/*
    * Copyright 2003 - 2013 The eFaps 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.
   *
   * Revision:        $Rev$
   * Last Changed:    $Date$
   * Last Changed By: $Author$
   */
  
  package org.efaps.db.print.value;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import org.efaps.admin.datamodel.Attribute;
  import org.efaps.admin.datamodel.Type;
  import org.efaps.db.print.ISelectPart;
  import org.efaps.db.print.OneSelect;
  import org.efaps.db.wrapper.SQLSelect;
  import org.efaps.util.EFapsException;
  
  /**
   * Abstract class used as base for all different types of ValueSelect.
   * A ValueSelct represents the part of a SQL-Statament that actual selects
   * a value.
   *
   * @author The eFaps Team
   * @version $Id$
   */
  public abstract class AbstractValueSelect
  {
  
      /**
       * List of column indexes the values have in the ResultSet returned from the
       * eFaps database.
       */
      private final List<Integer> colIndexs = new ArrayList<Integer>();
  
      /**
       * Parent of this AbstractValueSelect.
       */
      private AbstractValueSelect parent;
  
      /**
       * Child of this AbstractValueSelect.
       */
      private AbstractValueSelect child;
  
      /**
       *  OneSelect this ValueSelect belongs to.
       */
      private final OneSelect oneSelect;
  
      /**
       * SelectPart this ValueSelect is connected to.
       */
      private ISelectPart parentSelectPart;
  
      /**
       * Constructor setting the OneSelect this valueselect belongs to.
       *
       * @param _oneSelect OneSelect
       */
      public AbstractValueSelect(final OneSelect _oneSelect)
      {
          this.oneSelect = _oneSelect;
          if (!this.oneSelect.getSelectParts().isEmpty()) {
              this.parentSelectPart = this.oneSelect.getSelectParts().get(this.oneSelect.getSelectParts().size() - 1);
          }
      }
  
      /**
       * Getter method for instance variable {@link #parent}.
       *
       * @return value of instance variable {@link #parent}
       */
      public AbstractValueSelect getParent()
      {
          return this.parent;
      }
  
      /**
       * Getter method for the instance variable {@link #parentSelectPart}.
       *
       * @return value of instance variable {@link #parentSelectPart}
       */
      public ISelectPart getParentSelectPart()
      {
         return this.parentSelectPart;
     }
 
     /**
      * Method must return a unique String to identify the class. This is used to
      * determine which class was instantiated instead of using "instanceof".
      *
      * @return unique name.
      */
     public abstract String getValueType();
 
     /**
      * Getter method for instance variable {@link #colIndexs}.
      *
      * @return instance variable {@link #colIndexs}
      */
     public List<Integer> getColIndexs()
     {
         return this.colIndexs;
     }
 
     /**
      * Method to set an AbstractValueSelect as the parent of this
      * AbstractValueSelect.
      *
      * @param _parent AbstractValueSelect to be set as parent
      */
     public void setParentValueSelect(final AbstractValueSelect _parent)
     {
         this.parent = _parent;
     }
 
     /**
      * Method adds an AbstractValueSelect as a child of this chain of
      * AbstractValueSelect.
      *
      * @param _valueSelect AbstractValueSelect to be added as child
      * @throws EFapsException on error
      */
     public void addChildValueSelect(final AbstractValueSelect _valueSelect)
         throws EFapsException
     {
         if (this.child == null) {
             this.child = _valueSelect;
             _valueSelect.setParentValueSelect(this);
         } else {
             this.child.addChildValueSelect(_valueSelect);
         }
     }
 
     /**
      * Method is used to add the select part for this ValueSelect to the select
      * statement. e.g. "select T0.ID, TO.TYPEID" etc.
      *
      * @param _type Type this ValueSelect belongs to
      * @param _select SQL select statement to be appended to
      * @param _tableIndex index of the table
      * @param _colIndex last index of the column
      * @return number of columns added to the select statement
      * @throws EFapsException on error
      */
     public int append2SQLSelect(final Type _type,
                                 final SQLSelect _select,
                                 final int _tableIndex,
                                 final int _colIndex)
         throws EFapsException
     {
         return 0;
     }
 
     /**
      * Method to get the value for the current object.
      *
      * @param _object current object
      * @throws EFapsException on error
      * @return object
      */
     public Object getValue(final Object _object)
         throws EFapsException
     {
         return _object;
     }
 
     /**
      * Method to get the value for a list of object.
      *
      * @param _objectList list of objects
      * @throws EFapsException on error
      * @return object
      */
     public Object getValue(final List<Object> _objectList)
         throws EFapsException
     {
         final List<Object> ret = new ArrayList<Object>();
         for (final Object object : _objectList) {
             ret.add(getValue(object));
         }
         return _objectList.size() > 0 ? (ret.size() > 1 ? ret : ret.get(0)) : null;
     }
 
     /**
      * Getter method for instance variable {@link #child}.
      *
      * @return value of instance variable {@link #child}
      */
     public AbstractValueSelect getChildValueSelect()
     {
         return this.child;
     }
 
     /**
      * Method to return the attribute related to this AbstractValueSelect.
      *
      * @return Attribute if exists, else null
      */
     public Attribute getAttribute()
     {
         return null;
     }
 
     /**
      * Getter method for the instance variable {@link #oneSelect}.
      *
      * @return value of instance variable {@link #oneSelect}
      */
     public OneSelect getOneSelect()
     {
         return this.oneSelect;
     }
 }