ParserUtil


1   /* ========================================================================
2    * JCommon : a free general purpose class library for the Java(tm) platform
3    * ========================================================================
4    *
5    * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
6    * 
7    * Project Info:  http://www.jfree.org/jcommon/index.html
8    *
9    * This library is free software; you can redistribute it and/or modify it 
10   * under the terms of the GNU Lesser General Public License as published by 
11   * the Free Software Foundation; either version 2.1 of the License, or 
12   * (at your option) any later version.
13   *
14   * This library is distributed in the hope that it will be useful, but 
15   * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
16   * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 
17   * License for more details.
18   *
19   * You should have received a copy of the GNU Lesser General Public
20   * License along with this library; if not, write to the Free Software
21   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
22   * USA.  
23   *
24   * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
25   * in the United States and other countries.]
26   * 
27   * ---------------
28   * ParserUtil.java
29   * ---------------
30   * (C)opyright 2002-2005, by Thomas Morgner and Contributors.
31   *
32   * Original Author:  Thomas Morgner (taquera@sherito.org);
33   * Contributor(s):   David Gilbert (for Object Refinery Limited);
34   *
35   * $Id: ParserUtil.java,v 1.3 2005/10/18 13:25:44 mungady Exp $
36   *
37   * Changes
38   * -------
39   * 21-May-2002 : Contains utility functions to make parsing easier.
40   * 10-Dec-2002 : Fixed issues reported by Checkstyle (DG);
41   * 29-Apr-2003 : Distilled from the JFreeReport project and moved into JCommon;
42   * 23-Sep-2003 : Minor Javadoc updates (DG);
43   *
44   */
45  package org.jfree.xml;
46  
47  import java.awt.BasicStroke  ;
48  import java.awt.Color  ;
49  import java.awt.Stroke  ;
50  import java.awt.geom.Rectangle2D  ;
51  import java.lang.reflect.Field  ;
52  
53  import org.xml.sax.Attributes  ;
54  import org.xml.sax.SAXException  ;
55  
56  /**
57   * Basic helper functions to ease up the process of parsing.
58   *
59   * @author Thomas Morgner
60   */
61  public class ParserUtil {
62  
63      /**
64       * Parses the string <code>text</code> into an int. If text is null or does not
65       * contain a parsable value, the message given in <code>message</code> is used to
66       * throw a SAXException.
67       *
68       * @param text  the text to parse.
69       * @param message  the error message if parsing fails.
70       *
71       * @return the int value.
72       *
73       * @throws SAXException if there is a problem with the parsing.
74       */
75      public static int parseInt(final String   text, final String   message) throws SAXException   {
76          if (text == null) {
77              throw new SAXException  (message);
78          }
79  
80          try {
81              return Integer.parseInt(text);
82          }
83          catch (NumberFormatException   nfe) {
84              throw new SAXException  ("NumberFormatError: " + message);
85          }
86      }
87  
88      /**
89       * Parses an integer.
90       *
91       * @param text  the text to parse.
92       * @param defaultVal  the default value.
93       *
94       * @return the integer.
95       */
96      public static int parseInt(final String   text, final int defaultVal) {
97          if (text == null) {
98              return defaultVal;
99          }
100 
101         try {
102             return Integer.parseInt(text);
103         }
104         catch (NumberFormatException   nfe) {
105             return defaultVal;
106         }
107     }
108 
109     /**
110      * Parses the string <code>text</code> into an float. If text is null or does not
111      * contain a parsable value, the message given in <code>message</code> is used to
112      * throw a SAXException.
113      *
114      * @param text  the text to parse.
115      * @param message  the error message if parsing fails.
116      *
117      * @return the float value.
118      *
119      * @throws SAXException if there is a problem with the parsing.
120      */
121     public static float parseFloat(final String   text, final String   message) throws SAXException   {
122         if (text == null) {
123             throw new SAXException  (message);
124         }
125         try {
126             return Float.parseFloat(text);
127         }
128         catch (NumberFormatException   nfe) {
129             throw new SAXException  ("NumberFormatError: " + message);
130         }
131     }
132 
133     /**
134      * Parses the string <code>text</code> into an float. If text is null or does not
135      * contain a parsable value, the message given in <code>message</code> is used to
136      * throw a SAXException.
137      *
138      * @param text  the text to parse.
139      * @param defaultVal the defaultValue returned if parsing fails.
140      *
141      * @return the float value.
142      */
143     public static float parseFloat(final String   text, final float defaultVal) {
144         if (text == null) {
145             return defaultVal;
146         }
147         try {
148             return Float.parseFloat(text);
149         }
150         catch (NumberFormatException   nfe) {
151             return defaultVal;
152         }
153     }
154 
155     /**
156      * Parses a boolean. If the string <code>text</code> contains the value of "true", the
157      * true value is returned, else false is returned.
158      *
159      * @param text  the text to parse.
160      * @param defaultVal  the default value.
161      *
162      * @return a boolean.
163      */
164     public static boolean parseBoolean(final String   text, final boolean defaultVal) {
165         if (text == null) {
166             return defaultVal;
167         }
168         return text.equalsIgnoreCase("true");
169     }
170 
171     /**
172      * Parses a string. If the <code>text</code> is null, defaultval is returned.
173      *
174      * @param text  the text to parse.
175      * @param defaultVal  the default value.
176      *
177      * @return a string.
178      */
179     public static String   parseString(final String   text, final String   defaultVal) {
180         if (text == null) {
181             return defaultVal;
182         }
183         return text;
184     }
185 
186     /**
187      * Creates a basic stroke given the width contained as float in the given string.
188      * If the string could not be parsed into a float, a basic stroke with the width of
189      * 1 is returned.
190      *
191      * @param weight  a string containing a number (the stroke weight).
192      *
193      * @return the stroke.
194      */
195     public static Stroke   parseStroke(final String   weight) {
196         try {
197             if (weight != null) {
198                 final Float   w = new Float  (weight);
199                 return new BasicStroke  (w.floatValue());
200             }
201         }
202         catch (NumberFormatException   nfe) {
203             //Log.warn("Invalid weight for stroke", nfe);
204         }
205         return new BasicStroke  (1);
206     }
207 
208     /**
209      * Parses a color entry. If the entry is in hexadecimal or ocal notation, the color is
210      * created using Color.decode(). If the string denotes a constant name of on of the color
211      * constants defined in java.awt.Color, this constant is used.
212      * <p>
213      * As fallback the color black is returned if no color can be parsed.
214      *
215      * @param color  the color (as a string).
216      *
217      * @return the paint.
218      */
219     public static Color   parseColor(final String   color) {
220         return parseColor(color, Color.black);
221     }
222 
223     /**
224      * Parses a color entry. If the entry is in hexadecimal or octal notation, the color is
225      * created using Color.decode(). If the string denotes a constant name of one of the color
226      * constants defined in java.awt.Color, this constant is used.
227      * <p>
228      * As fallback the supplied default value is returned if no color can be parsed.
229      *
230      * @param color  the color (as a string).
231      * @param defaultValue  the default value (returned if no color can be parsed).
232      *
233      * @return the paint.
234      */
235     public static Color   parseColor(final String   color, final Color   defaultValue) {
236         if (color == null) {
237             return defaultValue;
238         }
239         try {
240             // get color by hex or octal value
241             return Color.decode(color);
242         }
243         catch (NumberFormatException   nfe) {
244             // if we can't decode lets try to get it by name
245             try {
246                 // try to get a color by name using reflection
247                 // black is used for an instance and not for the color itselfs
248                 final Field   f = Color  .class.getField(color);
249 
250                 return (Color  ) f.get(null);
251             }
252             catch (Exception   ce) {
253                 //Log.warn("No such Color : " + color);
254                 // if we can't get any color return black
255                 return defaultValue;
256             }
257         }
258     }
259 
260 
261     /**
262      * Parses a position of an element. If a relative postion is given, the returnvalue
263      * is a negative number between 0 and -100.
264      *
265      * @param value  the value.
266      * @param exceptionMessage  the exception message.
267      *
268      * @return the float value.
269      *
270      * @throws SAXException if there is a problem parsing the string.
271      */
272     public static float parseRelativeFloat(final String   value, final String   exceptionMessage)
273         throws SAXException   {
274         if (value == null) {
275             throw new SAXException  (exceptionMessage);
276         }
277         final String   tvalue = value.trim();
278         if (tvalue.endsWith("%")) {
279             final String   number = tvalue.substring(0, tvalue.indexOf("%"));
280             final float f = parseFloat(number, exceptionMessage) * -1.0f;
281             return f;
282         }
283         else {
284             return parseFloat(tvalue, exceptionMessage);
285         }
286     }
287 
288     /**
289      * Parses an element position. The position is stored in the attributes "x", "y", "width" and
290      * "height". The attributes are allowed to have relative notion.
291      *
292      * @param atts  the attributes.
293      *
294      * @return the element position.
295      *
296      * @throws SAXException if there is a problem getting the element position.
297      */
298     public static Rectangle2D   getElementPosition(final Attributes   atts) throws SAXException   {
299         final float x = ParserUtil.parseRelativeFloat(atts.getValue("x"),
300             "Element x not specified");
301         final float y = ParserUtil.parseRelativeFloat(atts.getValue("y"),
302             "Element y not specified");
303         final float w = ParserUtil.parseRelativeFloat(atts.getValue("width"),
304             "Element width not specified");
305         final float h = ParserUtil.parseRelativeFloat(atts.getValue("height"),
306             "Element height not specified");
307         final Rectangle2D.Float   retval = new Rectangle2D.Float  (x, y, w, h);
308         return retval;
309     }
310 
311 }
312
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