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    1   /*
    2    * Licensed to the Apache Software Foundation (ASF) under one
    3    * or more contributor license agreements.  See the NOTICE file
    4    * distributed with this work for additional information
    5    * regarding copyright ownership.  The ASF licenses this file
    6    * to you under the Apache License, Version 2.0 (the
    7    * "License"); you may not use this file except in compliance
    8    * with the License.  You may obtain a copy of the License at
    9    *
    10   *   http://www.apache.org/licenses/LICENSE-2.0
    11   *
    12   * Unless required by applicable law or agreed to in writing,
    13   * software distributed under the License is distributed on an
    14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    15   * KIND, either express or implied.  See the License for the
    16   * specific language governing permissions and limitations
    17   * under the License.
    18   */
    19  package org.apache.myfaces.shared_orchestra.renderkit;
    20
    21  import javax.faces.context.ExternalContext;
    22  import javax.faces.context.FacesContext;
    23  import java.util.Map;
    24
    25  /**
    26   * @author Thomas Spiegl
    27   */
    28  public class ViewSequenceUtils {
    29      private static final String SEQUENCE_PARAM = "jsf_sequence";
    30
    31      /**
    32       * Increments view sequence by 1.
    33       *
    34       * @param facescontext
    35       */
    36      public static void nextViewSequence(FacesContext facescontext) {
    37          ExternalContext externalContext = facescontext.getExternalContext();
    38          Object sessionObj = externalContext.getSession(true);
    39          synchronized (sessionObj) // synchronized to increase sequence if multiple requests
    40          // are handled at the same time for the session
    41          {
    42              Map map = externalContext.getSessionMap();
    43              Integer sequence = (Integer) map.get(SEQUENCE_PARAM);
    44              if (sequence == null || sequence.intValue() == Integer.MAX_VALUE) {
    45                  sequence = new Integer(1);
    46              }
    47              else {
    48                  sequence = new Integer(sequence.intValue() + 1);
    49              }
    50              map.put(SEQUENCE_PARAM, sequence);
    51              externalContext.getRequestMap().put(SEQUENCE_PARAM, sequence);
    52          }
    53      }
    54
    55      /**
    56       * Returns current view sequence and sets current view sequence to Integer(1) if
    57       * current sequence value is NULL.
    58       *
    59       * @param facescontext
    60       * @return
    61       */
    62      public static Integer getViewSequence(FacesContext facescontext) {
    63          Map map = facescontext.getExternalContext().getRequestMap();
    64          Integer sequence = (Integer) map.get(SEQUENCE_PARAM);
    65          if (sequence == null) {
    66              sequence = new Integer(1);
    67              map.put(SEQUENCE_PARAM, sequence);
    68
    69              synchronized (facescontext.getExternalContext().getSession(true)) {
    70                  facescontext.getExternalContext().getSessionMap().put(SEQUENCE_PARAM, sequence);
    71              }
    72          }
    73          return sequence;
    74      }
    75
    76
    77      /**
    78       * Current view sequence, may be NULL!
    79       *
    80       * @param context
    81       * @return
    82       */
    83      public static Integer getCurrentSequence(FacesContext context) {
    84          Map map = context.getExternalContext().getSessionMap();
    85          return (Integer) map.get(SEQUENCE_PARAM);
    86      }
    87
    88  }