AddParamTag


1   /**
2    * Copyright (c) 2003 held jointly by the individual authors. This library is
3    * free software; you can redistribute it and/or modify it under the terms of
4    * the GNU Lesser General Public License as published by the Free Software
5    * Foundation; either version 2.1 of the License, or (at your option) any later
6    * version. This library is distributed in the hope that it will be useful, but
7    * WITHOUT ANY WARRANTY; with out even the implied warranty of MERCHANTABILITY
8    * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
9    * License for more details. You should have received a copy of the GNU Lesser
10   * General Public License along with this library; if not, write to the Free
11   * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
12   * USA. > http://www.gnu.org/copyleft/lesser.html >
13   * http://www.opensource.org/licenses/lgpl-license.php
14   */
15  package net.mlw.vlh.web.tag;
16  
17  import java.lang.reflect.InvocationTargetException  ;
18  
19  import javax.servlet.jsp.JspException  ;
20  import javax.servlet.jsp.tagext.BodyTagSupport  ;
21  
22  import net.mlw.vlh.web.tag.support.ParamAddable;
23  import net.mlw.vlh.web.tag.support.Spacer;
24  import net.mlw.vlh.web.util.JspUtils;
25  
26  import org.apache.commons.beanutils.PropertyUtils;
27  import org.apache.commons.logging.Log;
28  import org.apache.commons.logging.LogFactory;
29  
30  /**
31   * The tag that append parameters to url for any paramaddable tag in table,such
32   * are tag for root and tag for action.
33   * 
34   * @author Andrej Zachar
35   * @version $Revision: 1.11 $ $Date: 2005/11/23 14:51:53 $
36   */
37  public class AddParamTag extends BodyTagSupport  
38  {
39  
40     private static final long serialVersionUID = 6118198463511925234L;
41  
42     /**
43      * Logger for this class
44      */
45     private static final Log LOGGER = LogFactory.getLog(AddParamTag.class);
46  
47     /** The name of the parameter used in rendered URL. */
48     private String   name = null;
49  
50     /**
51      * The name of the dynamic property, which values are used like the
52      * attribute value, but dynamicaly retrevied for the each row.
53      */
54     private String   property = null;
55  
56     /**
57      * The static value of the attribute name used in rendered URL like
58      * url?(ACTION_TEMP_PARAM_PREFIX)name=value .
59      */
60     private String   value = null;
61  
62     /**
63      * if true, append prefix ACTION_TEMP_PARAM_PREFIX before every action
64      * parameter.
65      */
66     private boolean temp = false;
67  
68     /**
69      * @throws NoSuchMethodException
70      * @throws InvocationTargetException
71      * @throws IllegalAccessException
72      * @see javax.servlet.jsp.tagext.Tag#doStartTag()
73      */
74     public int doStartTag() throws JspException  
75     {
76        ParamAddable parent = (ParamAddable) JspUtils.getParent(this, ParamAddable.class);
77  
78        if ((property != null) && (value != null))
79        {
80           final String   message = "For one parameter" + name
81                 + "you can not use two values (first dynamic from the property, 2nd static from the value";
82           LOGGER.error(message);
83           throw new JspException  (message);
84        }
85  
86        if (name == null)
87        {
88           // use the same name as the name of property, if name is not
89           // specified
90           name = property;
91        }
92  
93        if (property != null)
94        {
95           DefaultRowTag rowTag = (DefaultRowTag) JspUtils.getParent(this, DefaultRowTag.class);
96           Object   bean = pageContext.getAttribute(rowTag.getBeanName());
97           if (bean != null && !(bean instanceof Spacer))
98           {
99              try
100             {
101                value = String.valueOf(PropertyUtils.getProperty(bean, property));
102             }
103             catch (Exception   e)
104             {
105                LOGGER.error("<vlh:addParam> Error getting property '" + property + "'.");
106                value = null;
107             }
108          }
109          else
110          {
111             if (LOGGER.isDebugEnabled())
112             {
113                LOGGER.debug("Row's JavaBean '" + rowTag.getBeanName() + "' is null or Valuelist is empty!");
114             }
115             value = null;
116          }
117       }
118 
119       if (value == null)
120       {
121          if (LOGGER.isInfoEnabled())
122          {
123             LOGGER.info("The param '" + addActionParamPrefix(name) + "' is skiped, because it's value is null!");
124          }
125       }
126       else
127       {
128 
129          parent.addParam(addActionParamPrefix(name), value);
130          if (LOGGER.isDebugEnabled())
131          {
132             LOGGER.debug("The param '" + addActionParamPrefix(name) + "' was added with the value '" + value + "'.");
133          }
134       }
135 
136       release();
137 
138       return SKIP_BODY;
139    }
140 
141    /**
142     * @param param
143     *            Add action param prefix if it is a temp parameter.
144     */
145    protected String   addActionParamPrefix(String   param)
146    {
147       if (isTemp())
148       {
149          return ActionTag.ACTION_TEMP_PARAM_PREFIX + param;
150       }
151       else
152       {
153          return param;
154       }
155    }
156 
157    /**
158     * @see javax.servlet.jsp.tagext.BodyTagSupport#doAfterBody()
159     */
160    public int doAfterBody() throws JspException  
161    {
162       bodyContent.clearBody();
163       return SKIP_BODY;
164    }
165 
166    /**
167     * @see javax.servlet.jsp.tagext.Tag#doEndTag()
168     */
169    public int doEndTag() throws JspException  
170    {
171       int result = super.doEndTag();
172       reset();
173       return result;
174    }
175 
176    /**
177     * @return Returns the property.
178     */
179    public String   getProperty()
180    {
181       return this.property;
182    }
183 
184    /**
185     * @param property
186     *            The property to set.
187     */
188    public void setProperty(String   property)
189    {
190       this.property = property;
191    }
192 
193    /**
194     * @return Returns the name.
195     */
196    public String   getName()
197    {
198       return this.name;
199    }
200 
201    /**
202     * @param name
203     *            The url parameter name to set.
204     */
205    public void setName(String   name)
206    {
207       this.name = name;
208    }
209 
210    /**
211     * @return Returns the value.
212     */
213    public String   getValue()
214    {
215       return this.value;
216    }
217 
218    /**
219     * @param value The value to set.
220     */
221    public void setValue(String   value)
222    {
223       this.value = value;
224    }
225 
226    /**
227     * @return Returns the temp.
228     */
229    public boolean isTemp()
230    {
231       return temp;
232    }
233 
234    /**
235     * Default is false. If true,
236     * append prefix ACTION_TEMP_PARAM_PREFIX before every action  parameter.
237     * @param temp The temp to set.
238     */
239    public void setTemp(boolean temp)
240    {
241       this.temp = temp;
242    }
243 
244    private void reset()
245    {
246       this.name = null;
247       this.property = null;
248       this.temp = false;
249       this.value = null;
250    }
251 
252    /**
253     * Called on a Tag handler to release state.
254     * The page compiler guarantees that JSP page implementation
255     * objects will invoke this method on all tag handlers,
256     * but there may be multiple invocations on doStartTag and doEndTag in between.
257     * 
258     * @see javax.servlet.jsp.tagext.Tag#release()
259     */
260    public void release()
261    {
262       super.release();
263       reset();
264    }
265 }
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