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    1   /*
    2    * $Id: GenericUIBean.java 497654 2007-01-19 00:21:57Z rgielen $
    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  package org.apache.struts2.components;
    22
    23  import javax.servlet.http.HttpServletRequest;
    24  import javax.servlet.http.HttpServletResponse;
    25
    26  import org.apache.struts2.views.annotations.StrutsTag;
    27  import org.apache.struts2.util.ContainUtil;
    28
    29  import com.opensymphony.xwork2.util.ValueStack;
    30
    31  /***
    32   * <!-- START SNIPPET: javadoc -->
    33   *
    34   * Renders an custom UI widget using the specified templates. Additional objects can be passed in to the template
    35   * using the param tags.<p/>
    36   *
    37   * <b>Freemarker:</b><p/>
    38   * Objects provided can be retrieve from within the template via $parameters._paramname_.<p/>
    39   *
    40   * <b>Jsp:</b><p/>
    41   * Objects provided can be retrieve from within the template via &lt;s:property value="%{parameters._paramname_}" /&gt;<p/>
    42   *
    43   *
    44   * In the bottom JSP and Velocity samples, two parameters are being passed in to the component. From within the
    45   * component, they can be accessed as:- <p/>
    46   *
    47   * <b>Freemarker:</b><p/>
    48   * $parameters.get('key1') and $parameters.get('key2') or $parameters.key1 and $parameters.key2<p/>
    49   *
    50   * <b>Jsp:</b><p/>
    51   * &lt;s:property value="%{parameters.key1}" /&gt; and &lt;s:property value="%{'parameters.key2'}" /&gt; or
    52   * &lt;s:property value="%{parameters.get('key1')}" /&gt; and &lt;s:property value="%{parameters.get('key2')}" /&gt;<p/>
    53   *
    54   * Currently, your custom UI components can be written in Velocity, JSP, or Freemarker, and the correct rendering
    55   * engine will be found based on file extension.<p/>
    56   *
    57   * <b>Remember:</b> the value params will always be resolved against the ValueStack so if you mean to pass a
    58   * string literal to your component, make sure to wrap it in quotes i.e. value="'value1'" otherwise, the the value
    59   * stack will search for an Object on the stack with a method of getValue1(). (now that i've written this, i'm not
    60   * entirely sure this is the case. i should verify this manana)<p/>
    61   *
    62   * <!-- END SNIPPET: javadoc -->
    63   *
    64   * <p/> <b>Examples</b>
    65   *
    66   * <pre>
    67   * <!-- START SNIPPET: example -->
    68   * JSP
    69   *     &lt;s:component template="/my/custom/component.vm"/&gt;
    70   *
    71   *       or
    72   *
    73   *     &lt;s:component template="/my/custom/component.vm"&gt;
    74   *       &lt;s:param name="key1" value="value1"/&gt;
    75   *       &lt;s:param name="key2" value="value2"/&gt;
    76   *     &lt;/s:component&gt;
    77   *
    78   * Velocity
    79   *     #s-component( "template=/my/custom/component.vm" )
    80   *
    81   *       or
    82   *
    83   *     #s-component( "template=/my/custom/component.vm" )
    84   *       #s-param( "name=key1" "value=value1" )
    85   *       #s-param( "name=key2" "value=value2" )
    86   *     #end
    87   *
    88   * Freemarker
    89   *    &lt;@s..component template="/my/custom/component.ftl" />
    90   *
    91   *      or
    92   *
    93   *    &lt;@s..component template="/my/custom/component.ftl"&gt;
    94   *       &lt;@s..param name="key1" value="%{'value1'}" /&gt;
    95   *       &lt;@s..param name="key2" value="%{'value2'}" /&gt;
    96   *    &lt;/@s..component&gt;
    97   *
    98   * <!-- END SNIPPET: example -->
    99   * </pre>
    100  *
    101  * <p/>
    102  *
    103  * <b>NOTE:</b>
    104  * <!-- START SNIPPET: note -->
    105  *
    106  * If Jsp is used as the template, the jsp template itself must lie within the
    107  * webapp itself and not the classpath. Unlike Freemarker or Velocity, JSP template
    108  * could not be picked up from the classpath.
    109  *
    110  * <!-- END SNIPPET: note -->
    111  *
    112  */
    113 @StrutsTag(name="component", tldTagClass="org.apache.struts2.views.jsp.ui.ComponentTag", description="Render a custom ui widget")
    114 public class GenericUIBean extends UIBean {
    115     private final static String TEMPLATE = "empty";
    116
    117     public GenericUIBean(ValueStack stack, HttpServletRequest request, HttpServletResponse response) {
    118         super(stack, request, response);
    119     }
    120
    121     public boolean contains(Object obj1, Object obj2) {
    122         return ContainUtil.contains(obj1, obj2);
    123     }
    124
    125     protected String getDefaultTemplate() {
    126         return TEMPLATE;
    127     }
    128 }