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Java > Open Source Codes > net > mlw > vlh > web > util > JspUtils


1 /**
2  * Copyright (c) 2003 held jointly by the individual authors.
3  *
4  * This library is free software; you can redistribute it and/or modify it
5  * under the terms of the GNU Lesser General Public License as published
6  * by the Free Software Foundation; either version 2.1 of the License, or
7  * (at your option) any later version.
8  *
9  * This library is distributed in the hope that it will be useful, but
10  * WITHOUT ANY WARRANTY; with out even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12  * GNU Lesser General Public License for more details.
13  *
14  * You should have received a copy of the GNU Lesser General Public License
15  * along with this library; if not, write to the Free Software Foundation,
16  * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
17  *
18  * > http://www.gnu.org/copyleft/lesser.html
19  * > http://www.opensource.org/licenses/lgpl-license.php
20  */
21 package net.mlw.vlh.web.util;
22
23 import java.io.IOException JavaDoc;
24 import java.text.MessageFormat JavaDoc;
25 import java.util.ArrayList JavaDoc;
26 import java.util.Calendar JavaDoc;
27 import java.util.Collection JavaDoc;
28 import java.util.Collections JavaDoc;
29 import java.util.Iterator JavaDoc;
30 import java.util.Locale JavaDoc;
31 import java.util.Map JavaDoc;
32 import java.util.StringTokenizer JavaDoc;
33
34 import javax.servlet.jsp.JspException JavaDoc;
35 import javax.servlet.jsp.JspWriter JavaDoc;
36 import javax.servlet.jsp.PageContext JavaDoc;
37 import javax.servlet.jsp.tagext.BodyContent JavaDoc;
38 import javax.servlet.jsp.tagext.Tag JavaDoc;
39
40 import org.apache.commons.logging.Log;
41 import org.apache.commons.logging.LogFactory;
42
43 /**
44  * A lot of this functionality is in the Struts ResponceUtils, but I do not want
45  * to create a dependicy to struts.
46  *
47  * @author Matthew L. Wilson, Andrej Zachar
48  * @version $Revision: 1.7 $ $Date: 2005/11/23 14:32:58 $
49  */
50 public final class JspUtils
51 {
52
53    private static final Log LOGGER = LogFactory.getLog(JspUtils.class);
54
55    /** Private to protect singleton. */
56    private JspUtils()
57    {
58    }
59
60    /**
61     * Write the specified text as the response to the writer associated with
62     * this page. <strong>WARNING </strong>- If you are writing body content from
63     * the <code>doAfterBody()</code> method of a custom tag class that
64     * implements <code>BodyTag</code>, you should be calling
65     * <code>writePrevious()</code> instead.
66     *
67     * @param pageContext
68     * The PageContext object for this page
69     * @param text
70     * The text to be written
71     *
72     * @exception JspException
73     * if an input/output error occurs
74     */
75    public static void write(PageContext JavaDoc pageContext, String JavaDoc text) throws JspException JavaDoc
76    {
77
78       JspWriter JavaDoc writer = pageContext.getOut();
79
80       try
81       {
82          writer.print(text);
83       }
84       catch (IOException JavaDoc e)
85       {
86          LOGGER.error("JspUtils.write() exception...", e);
87          throw new JspException JavaDoc(e);
88       }
89
90    }
91
92    /**
93     * Write the specified text as the response to the writer associated with the
94     * body content for the tag within which we are currently nested.
95     *
96     * @param pageContext
97     * The PageContext object for this page
98     * @param text
99     * The text to be written
100     *
101     * @exception JspException
102     * if an input/output error occurs
103     */
104    public static void writePrevious(PageContext JavaDoc pageContext, String JavaDoc text) throws JspException JavaDoc
105    {
106       JspWriter JavaDoc writer = pageContext.getOut();
107       if (writer instanceof BodyContent JavaDoc)
108       {
109          writer = ((BodyContent JavaDoc) writer).getEnclosingWriter();
110       }
111
112       try
113       {
114          writer.print(text);
115       }
116       catch (IOException JavaDoc e)
117       {
118          LOGGER.error("JspUtils.writePrevious() exception...", e);
119          throw new JspException JavaDoc(e);
120       }
121
122    }
123
124    /**
125     * Converts a stirng into a collection of strings.
126     *
127     * @param value
128     * The string to be parsed.
129     * @param token
130     * The token to be used.
131     * @return A Collection of String(s).
132     */
133    public static Collection JavaDoc toCollection(String JavaDoc value, String JavaDoc token)
134    {
135       if (value == null || value.length() == 0)
136       {
137          return Collections.EMPTY_LIST;
138       }
139
140       Collection JavaDoc elements = new ArrayList JavaDoc();
141       for (StringTokenizer JavaDoc st = new StringTokenizer JavaDoc(value, token); st.hasMoreElements();)
142       {
143          elements.add(st.nextToken());
144       }
145
146       return elements;
147    }
148
149    public static String JavaDoc format(Object JavaDoc value, String JavaDoc format, Locale JavaDoc loc)
150    {
151       if (value == null)
152       {
153          return "";
154       }
155       else
156       {
157          if (value instanceof Number JavaDoc)
158          {
159             if (format == null || format.length() == 0)
160             {
161                return value.toString();
162             }
163             MessageFormat JavaDoc mf = new MessageFormat JavaDoc("{0,number," + format + "}");
164             if (loc != null)
165             {
166                mf.setLocale(loc);
167                mf.applyPattern(mf.toPattern());
168             }
169
170             return mf.format(new Object JavaDoc[]
171             { value });
172          }
173          else if (value instanceof java.util.Date JavaDoc)
174          {
175             if (format == null || format.length() == 0)
176             {
177                //TODO: get the default date format in here somehow. format =
178 // SystemProperties.getProperty("default.dateFormat", "EEE, MMM
179 // d, ''yy");
180 format = "EEE, MMM d, ''yy";
181             }
182             MessageFormat JavaDoc mf = new MessageFormat JavaDoc("{0,date," + format + "}");
183             if (loc != null)
184             {
185                mf.setLocale(loc);
186                mf.applyPattern(mf.toPattern());
187             }
188             return mf.format(new Object JavaDoc[]
189             { value });
190          }
191          else if (value instanceof Calendar JavaDoc)
192          {
193             Calendar JavaDoc calendar = (Calendar JavaDoc) value;
194             if (format == null || format.length() == 0)
195             {
196                //TODO: get the default date format in here somehow. format =
197 // SystemProperties.getProperty("default.dateFormat", "EEE, MMM
198 // d, ''yy");
199 format = "EEE, MMM d, ''yy";
200             }
201
202             MessageFormat JavaDoc mf = new MessageFormat JavaDoc("{0,date," + format + "}");
203             if (loc != null)
204             {
205                mf.setLocale(loc);
206                mf.applyPattern(mf.toPattern());
207             }
208             return mf.format(new Object JavaDoc[]
209             { value });
210          }
211          else
212          {
213             return value.toString();
214          }
215
216       }
217    }
218
219    public static String JavaDoc toAttributesString(Map JavaDoc map)
220    {
221       StringBuffer JavaDoc sb = new StringBuffer JavaDoc();
222
223       for (Iterator JavaDoc iter = map.keySet().iterator(); iter.hasNext();)
224       {
225          Object JavaDoc key = iter.next();
226          sb.append(key).append("=\"").append(map.get(key)).append("\" ");
227       }
228
229       return sb.toString();
230    }
231
232    public static Tag JavaDoc getParent(Tag JavaDoc self, Class JavaDoc klass) throws JspException JavaDoc
233    {
234       Tag JavaDoc tag = self.getParent();
235
236       while (!(klass.isAssignableFrom(tag.getClass())))
237       {
238          tag = tag.getParent();
239          if (tag == null)
240          {
241             final String JavaDoc message = "Parent tag of class " + klass + " of the tag's class " + self + " was not found.";
242             LOGGER.error(message);
243             throw new JspException JavaDoc(message);
244          }
245       }
246       return tag;
247    }
248 }
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