001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements.  See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership.  The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the
007     * "License"); you may not use this file except in compliance
008     * with the License.  You may obtain a copy of the License at
009     *
010     *   http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing,
013     * software distributed under the License is distributed on an
014     * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015     * KIND, either express or implied.  See the License for the
016     * specific language governing permissions and limitations
017     * under the License.
018     */
019    
020    package org.apache.myfaces.tobago.component;
021    
022    import org.apache.commons.logging.Log;
023    import org.apache.commons.logging.LogFactory;
024    import org.apache.myfaces.tobago.event.PageActionEvent;
025    import static org.apache.myfaces.tobago.TobagoConstants.ATTR_FIRST;
026    
027    import javax.faces.context.FacesContext;
028    import javax.faces.el.EvaluationException;
029    import javax.faces.el.MethodBinding;
030    import javax.faces.el.MethodNotFoundException;
031    import javax.faces.el.ValueBinding;
032    
033    public class Pager extends MethodBinding {
034    
035      private static final Log LOG = LogFactory.getLog(Pager.class);
036    
037      public Class getType(FacesContext facescontext)
038          throws MethodNotFoundException {
039        return String.class;
040      }
041    
042      public Object invoke(FacesContext facesContext, Object[] aobj)
043          throws EvaluationException {
044        if (aobj[0] instanceof PageActionEvent) {
045          PageActionEvent pageEvent = (PageActionEvent) aobj[0];
046    
047          UIData sheet = pageEvent.getSheet();
048          int first = -1;
049    
050          if (LOG.isDebugEnabled()) {
051            LOG.debug("action = '" + pageEvent.getAction().name() + "'");
052          }
053    
054          int start;
055          switch (pageEvent.getAction()) {
056            case FIRST:
057              first = 0;
058              break;
059            case PREV:
060              start = sheet.getFirst() - sheet.getRows();
061              first = start < 0 ? 0 : start;
062              break;
063            case NEXT:
064              if (sheet.hasRowCount()) {
065                start = sheet.getFirst() + sheet.getRows();
066                first = start > sheet.getRowCount() ? sheet.getLastPageIndex() : start;
067              } else {
068                if (sheet.isAtEnd()) {
069                  first = sheet.getFirst();
070                } else {
071                  first = sheet.getFirst() + sheet.getRows();
072                }
073              }
074              break;
075            case LAST:
076              first = sheet.getLastPageIndex();
077              break;
078            case TO_ROW:
079              start = pageEvent.getValue() - 1;
080              if (start > sheet.getLastPageIndex()) {
081                start = sheet.getLastPageIndex();
082              } else if (start < 0) {
083                start = 0;
084              }
085              first = start;
086              break;
087            case TO_PAGE:
088              start = pageEvent.getValue() - 1;
089              if (LOG.isDebugEnabled()) {
090                LOG.debug("start = " + start + "  sheet.getRows() = "
091                    + sheet.getRows() + " => start = " + (start * sheet.getRows()));
092              }
093              start = start * sheet.getRows();
094              if (start > sheet.getLastPageIndex()) {
095                start = sheet.getLastPageIndex();
096              } else if (start < 0) {
097                start = 0;
098              }
099              first = start;
100              break;
101            default:
102              // can't happen
103          }
104          ValueBinding valueBinding = sheet.getValueBinding(ATTR_FIRST);
105          if (valueBinding != null) {
106            valueBinding.setValue(facesContext, first);
107          } else {
108            sheet.setFirst(first);
109          }
110    
111          sheet.getSheetState(facesContext).setFirst(first);
112    //      sheet.queueEvent(new SheetStateChangeEvent(sheet));
113        } else {
114          if (LOG.isDebugEnabled()) {
115            LOG.debug("aobj[0] instanceof '" + aobj[0] + "'");
116          }
117        }
118    
119        return null;
120      }
121    }
122