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    1   package org.apache.turbine.om;
    2
    3
    4   /*
    5    * Licensed to the Apache Software Foundation (ASF) under one
    6    * or more contributor license agreements.  See the NOTICE file
    7    * distributed with this work for additional information
    8    * regarding copyright ownership.  The ASF licenses this file
    9    * to you under the Apache License, Version 2.0 (the
    10   * "License"); you may not use this file except in compliance
    11   * with the License.  You may obtain a copy of the License at
    12   *
    13   *   http://www.apache.org/licenses/LICENSE-2.0
    14   *
    15   * Unless required by applicable law or agreed to in writing,
    16   * software distributed under the License is distributed on an
    17   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    18   * KIND, either express or implied.  See the License for the
    19   * specific language governing permissions and limitations
    20   * under the License.
    21   */
    22
    23
    24  import java.util.HashMap;
    25  import java.util.Map;
    26
    27  import org.apache.fulcrum.pool.Recyclable;
    28  import org.apache.turbine.services.pull.ApplicationTool;
    29
    30  /**
    31   * A Pull tool to make om objects available to a template
    32   *
    33   * @author <a href="mailto:jmcnally@collab.net">John D. McNally</a>
    34   * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
    35   * @version $Id: OMTool.java 1078552 2011-03-06 19:58:46Z tv $
    36   */
    37  public class OMTool implements ApplicationTool, Recyclable
    38  {
    39      // private RunData data;
    40      protected HashMap<String, Object> omMap;
    41
    42      // note the following could be a static attribute to reduce memory
    43      // footprint. Might require a service to front load the
    44      // PullHelpers to avoid MT issues. A multiple write is not so bad
    45      // though
    46
    47      /** The cache of PullHelpers. **/
    48      private static Map<String, OMTool.PullHelper> pullMap = new HashMap<String, OMTool.PullHelper>();
    49
    50      /**
    51       *  The Factory responsible for retrieving the
    52       *  objects from storage
    53       */
    54      protected RetrieverFactory omFactory;
    55
    56      public OMTool()throws Exception
    57      {
    58          omMap = new HashMap<String, Object>();
    59          //String className = Turbine.getConfiguration()
    60          //       .getString("tool.om.factory");
    61          //        RetrieverFactory omFactory =
    62          //            (RetrieverFactory)Class.forName(className).newInstance();
    63      }
    64
    65      /**
    66       * Prepares tool for a single request
    67       */
    68      public void init(Object runData)
    69      {
    70          // data = (RunData)runData;
    71      }
    72
    73      /**
    74       * Implementation of ApplicationTool interface is not needed for this
    75       * method as the tool is request scoped
    76       */
    77      public void refresh()
    78      {
    79          // empty
    80      }
    81
    82      /**
    83       * Inner class to present a nice interface to the template designer
    84       */
    85      protected class PullHelper
    86      {
    87          String omName;
    88
    89          protected PullHelper(String omName)
    90          {
    91              this.omName = omName;
    92          }
    93
    94          public Object setKey(String key)
    95              throws Exception
    96          {
    97              Object om = null;
    98
    99              String inputKey = omName + key;
    100             if (omMap.containsKey(inputKey))
    101             {
    102                 om = omMap.get(inputKey);
    103             }
    104             else
    105             {
    106                 om = omFactory.getInstance(omName).retrieve(key);
    107                 omMap.put(inputKey, om);
    108             }
    109
    110             return om;
    111         }
    112     }
    113
    114     public Object get(String omName) throws Exception
    115     {
    116         if (!pullMap.containsKey(omName))
    117         {
    118             // MT could overwrite a PullHelper, but that is not a problem
    119             // should still synchronize to avoid two threads adding at
    120             // same time
    121             synchronized (this.getClass())
    122             {
    123                 pullMap.put(omName, new OMTool.PullHelper(omName));
    124             }
    125         }
    126
    127         return pullMap.get(omName);
    128     }
    129
    130     public Object get(String omName, String key) throws Exception
    131     {
    132         return ((OMTool.PullHelper) get(omName)).setKey(key);
    133     }
    134
    135
    136     public String getName()
    137     {
    138         return "om";
    139     }
    140
    141
    142     // ****************** Recyclable implementation ************************
    143
    144     private boolean disposed;
    145
    146     /**
    147      * Recycles the object for a new client. Recycle methods with
    148      * parameters must be added to implementing object and they will be
    149      * automatically called by pool implementations when the object is
    150      * taken from the pool for a new client. The parameters must
    151      * correspond to the parameters of the constructors of the object.
    152      * For new objects, constructors can call their corresponding recycle
    153      * methods whenever applicable.
    154      * The recycle methods must call their super.
    155      */
    156     public void recycle()
    157     {
    158         disposed = false;
    159     }
    160
    161     /**
    162      * Disposes the object after use. The method is called
    163      * when the object is returned to its pool.
    164      * The dispose method must call its super.
    165      */
    166     public void dispose()
    167     {
    168         omMap.clear();
    169         // data = null;
    170         disposed = true;
    171     }
    172
    173     /**
    174      * Checks whether the recyclable has been disposed.
    175      * @return true, if the recyclable is disposed.
    176      */
    177     public boolean isDisposed()
    178     {
    179         return disposed;
    180     }
    181 }
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