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    1   package org.apache.turbine.om;
    2
    3   /*
    4    * Licensed to the Apache Software Foundation (ASF) under one
    5    * or more contributor license agreements.  See the NOTICE file
    6    * distributed with this work for additional information
    7    * regarding copyright ownership.  The ASF licenses this file
    8    * to you under the Apache License, Version 2.0 (the
    9    * "License"); you may not use this file except in compliance
    10   * with the License.  You may obtain a copy of the License at
    11   *
    12   *   http://www.apache.org/licenses/LICENSE-2.0
    13   *
    14   * Unless required by applicable law or agreed to in writing,
    15   * software distributed under the License is distributed on an
    16   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    17   * KIND, either express or implied.  See the License for the
    18   * specific language governing permissions and limitations
    19   * under the License.
    20   */
    21
    22  import java.util.concurrent.ConcurrentHashMap;
    23  import java.util.concurrent.ConcurrentMap;
    24
    25  import org.apache.fulcrum.pool.Recyclable;
    26  import org.apache.turbine.Turbine;
    27  import org.apache.turbine.services.pull.ApplicationTool;
    28
    29  /**
    30   * A Pull tool to make om objects available to a template
    31   *
    32   * @author <a href="mailto:jmcnally@collab.net">John D. McNally</a>
    33   * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
    34   * @version $Id: OMTool.java 1706425 2015-10-02 14:47:51Z tv $
    35   */
    36  public class OMTool implements ApplicationTool, Recyclable
    37  {
    38      protected ConcurrentHashMap<String, Object> omMap;
    39
    40      // note the following could be a static attribute to reduce memory
    41      // footprint. Might require a service to front load the
    42      // PullHelpers to avoid MT issues. A multiple write is not so bad
    43      // though
    44
    45      /** The cache of PullHelpers. **/
    46      private ConcurrentMap<String, OMTool.PullHelper> pullMap =
    47              new ConcurrentHashMap<String, OMTool.PullHelper>();
    48
    49      /**
    50       *  The Factory responsible for retrieving the
    51       *  objects from storage
    52       */
    53      protected RetrieverFactory omFactory;
    54
    55      /**
    56       * Default constructor
    57       * @throws Exception if creating the factory fails
    58       */
    59      public OMTool() throws Exception
    60      {
    61          omMap = new ConcurrentHashMap<String, Object>();
    62          String className = Turbine.getConfiguration().getString("tool.om.factory");
    63          this.omFactory = (RetrieverFactory)Class.forName(className).newInstance();
    64      }
    65
    66      /**
    67       * Prepares tool for a single request
    68       *
    69       * @param data the initialization data
    70       */
    71      @Override
    72      public void init(Object data)
    73      {
    74          // data = (RunData)data;
    75      }
    76
    77      /**
    78       * Implementation of ApplicationTool interface is not needed for this
    79       * method as the tool is request scoped
    80       */
    81      @Override
    82      public void refresh()
    83      {
    84          // empty
    85      }
    86
    87      /**
    88       * Inner class to present a nice interface to the template designer
    89       */
    90      protected class PullHelper
    91      {
    92          String omName;
    93
    94          protected PullHelper(String omName)
    95          {
    96              this.omName = omName;
    97          }
    98
    99          public Object setKey(String key)
    100             throws Exception
    101         {
    102             Object om = null;
    103             String inputKey = omName + key;
    104
    105             if (omMap.containsKey(inputKey))
    106             {
    107                 om = omMap.get(inputKey);
    108             }
    109             else
    110             {
    111                 om = omFactory.getInstance(omName).retrieve(key);
    112                 omMap.put(inputKey, om);
    113             }
    114
    115             return om;
    116         }
    117     }
    118
    119     /**
    120      * Get the {@link PullHelper} object with the given name
    121      * @param omName the object name
    122      * @return the PullHelper
    123      * @throws Exception if retrieving the object fails
    124      */
    125     public PullHelper get(String omName) throws Exception
    126     {
    127         PullHelper ph = pullMap.putIfAbsent(omName, new OMTool.PullHelper(omName));
    128         if (ph == null)
    129         {
    130             return pullMap.get(omName);
    131         }
    132
    133         return ph;
    134     }
    135
    136     /**
    137      * Get the object with the given name and key
    138      * @param omName the object name
    139      * @param key the object key
    140      * @return the object
    141      * @throws Exception if retrieving the object fails
    142      */
    143     public Object get(String omName, String key) throws Exception
    144     {
    145         return get(omName).setKey(key);
    146     }
    147
    148     // ****************** Recyclable implementation ************************
    149
    150     private boolean disposed;
    151
    152     /**
    153      * Recycles the object for a new client. Recycle methods with
    154      * parameters must be added to implementing object and they will be
    155      * automatically called by pool implementations when the object is
    156      * taken from the pool for a new client. The parameters must
    157      * correspond to the parameters of the constructors of the object.
    158      * For new objects, constructors can call their corresponding recycle
    159      * methods whenever applicable.
    160      * The recycle methods must call their super.
    161      */
    162     @Override
    163     public void recycle()
    164     {
    165         disposed = false;
    166     }
    167
    168     /**
    169      * Disposes the object after use. The method is called
    170      * when the object is returned to its pool.
    171      * The dispose method must call its super.
    172      */
    173     @Override
    174     public void dispose()
    175     {
    176         omMap.clear();
    177         disposed = true;
    178     }
    179
    180     /**
    181      * Checks whether the recyclable has been disposed.
    182      * @return true, if the recyclable is disposed.
    183      */
    184     @Override
    185     public boolean isDisposed()
    186     {
    187         return disposed;
    188     }
    189 }