/*
    * Copyright 2002,2004 The Apache Software Foundation.
    * 
    * 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 org.apache.commons.scaffold.sql;
  
  
  import java.util.Collection;
  
  import org.apache.commons.scaffold.lang.Tokens;
  
  import org.apache.commons.scaffold.lang.ParameterException;
  import org.apache.commons.scaffold.lang.ResourceException;
  
  import org.apache.commons.scaffold.util.ProcessResult;
  import org.apache.commons.scaffold.util.ProcessResultBase;
  import org.apache.commons.scaffold.util.ResultList;
  import org.apache.commons.scaffold.util.ResultListBase;
  import org.apache.commons.scaffold.util.Scroller;
  import org.apache.commons.scaffold.util.ScrollerBean;
  
  
  /**
   * Base class for scrolling searches.
   *
   * @author Ted Husted
   * @version $Revision: 155464 $ $Date: 2005-02-26 13:26:54 +0000 (Sat, 26 Feb 2005) $
   */
  public class ScrollerBeanBase extends StorageBeanBase implements ScrollerBean {
  
  
      /**
       * The entry (or page) from which to scroll [1].
       */
      public Integer scrollFrom = new Integer(1);
  
  
       // See interface for Javadoc
      public Integer getScrollFrom() {
          return scrollFrom;
      }
  
  
       // See interface for Javadoc
      public void setScrollFrom(Integer scrollFrom) {
          this.scrollFrom = scrollFrom;
      }
  
  
       // See interface for Javadoc
      public Integer scrollOffset() {
          int offset = getScrollFrom().intValue();
          return new Integer(--offset);
      }
  
  
       // See interface for Javadoc
      public int scrollRows() {
          return Scroller.SCROLL_ROWS;
  
      }
  
  
       // See interface for Javadoc
      public String countKey() {
          return null;
      }
  
  
       // See interface for Javadoc
      public boolean hasParameter() {
          return false;
      }
  
  
       // See interface for Javadoc
      public Object searchValue() {
          return null;
      }
  
  
       // See interface for Javadoc
      public boolean isLike() {
          return false;
      }
  
  
      // See interface for Javadoc
     public int entryCount() throws ResourceException {
 
         if (hasParameter()) {
 
             if (isLike())
                 return count(countKey(),like(searchValue().toString()));
             else
                 return count(countKey(),searchValue());
 
         }
 
        return count(countKey());
 
     }
 
 
      // See interface for Javadoc
     public String commandKey() {
         return null;
     }
 
 
 
      // See interface for Javadoc
     public String searchProperty() {
         return null;
     }
 
 
      // See interface for Javadoc
     public String searchLabel() {
         return searchProperty();
     }
 
 
      // See interface for Javadoc
     public boolean failsOnEmpty () {
         return false;
     }
 
 
      // See interface for Javadoc
     public String tokenEmptyMessage() {
         return Tokens.DATA_ACCESS_EMPTY;
     }
 
 
      // See interface for Javadoc
     public String tokenEmptyDispatch() {
         return Tokens.FAILURE;
     }
 
 
      // See interface for Javadoc
     public Object[] scrollerParams(String parameter) {
 
         Object[] parameters = null;
 
         if (hasParameter()) {
 
             parameters = new Object[3];
             parameters[0] = parameter;
             parameters[1] = scrollOffset();
             parameters[2] = new Integer(scrollRows());
         }
 
         else {
 
             parameters = new Object[2];
             parameters[0] = scrollOffset();
             parameters[1] = new Integer(scrollRows());
         }
 
         return parameters;
     }
 
 
      // See interface for Javadoc
     public Collection result(Object target, Object parameter)
             throws ResourceException {
 
         String param = null;
         if (null!=parameter) {
             if (isLike()) param = like(parameter.toString());
             else param = parameter.toString();
         }
 
         return findCollection(
             target,
             commandKey(),
             scrollerParams(param)
         );
     }
 
 
      // See interface for Javadoc
     public Scroller newScroller(int entries) throws ResourceException {
 
         Scroller scroller = new Scroller();
         scroller.calculate(
             entries,
             getScrollFrom().intValue(),
             entryCount(),
             scrollRows()
             );
 
         if (hasParameter()) {
             java.util.Map map = new java.util.HashMap();
             map.put(searchProperty(),searchValue());
             scroller.setParameters(map);
         }
 
         return scroller;
     }
 
 
      // See interface for Javadoc
     public void listLegend(ResultList list) {
 
         if (hasParameter())
             list.setLegend(searchLabel(),searchValue().toString());
         else
             list.setLegend(searchLabel());
 
     }
 
 
      // See interface for Javadoc
     public ProcessResult scrollerSearch() throws Exception {
 
         Object key = null;
         if (hasParameter()) {
             key = searchValue();
             if (null==key) {
                 throw new ParameterException();
             }
         }
 
         ResultList list = new ResultListBase (result(this,key));
         Scroller scroller = newScroller(list.size());
         list.setScroller(scroller);
         ProcessResult result = new ProcessResultBase(list);
 
         listLegend(list);
 
         if (failsOnEmpty() && list.isEmpty()) {
             result.addMessage(tokenEmptyMessage());
             result.setDispatch(tokenEmptyDispatch());
         }
         return result;
 
    } // end scrollerSearch
 
 } // end ScrollerBeanBase