LZUtils


1   /* *****************************************************************************
2    * LZUtils.java
3    * ****************************************************************************/
4   
5   /* J_LZ_COPYRIGHT_BEGIN *******************************************************
6   * Copyright 2001-2004 Laszlo Systems, Inc.  All Rights Reserved.              *
7   * Use is subject to license terms.                                            *
8   * J_LZ_COPYRIGHT_END *********************************************************/
9   
10  package org.openlaszlo.utils;
11  
12  import java.util.Enumeration  ;
13  import java.util.Properties  ;
14  import java.util.Date  ;
15  import java.util.GregorianCalendar  ;
16  import java.util.Calendar  ;
17  
18  /**
19   * Class for miscellaneous utility functions.
20   */
21  public class LZUtils
22  {
23      /**
24       * Get int from object.
25       *
26       * @param o number to convert.
27       * @return if null or non-integer, returns 0.
28       */
29      static public int getInt(Object   o)
30      {
31          if (o == null)
32              return 0;
33  
34          if (! o.getClass().getName().equals("java.lang.Integer"))
35              return 0;
36  
37          return ((Integer  )o).intValue();
38      }
39  
40  
41      /**
42       * Get string from object.
43       *
44       * @param o object to convert.
45       * @return if null or non-string, returns null.
46       */
47      static public String   getStr(Object   o)
48      {
49          return getStr(o, true);
50      }
51  
52  
53      /**
54       * Get string from object.
55       *
56       * @param o object to convert.
57       * @param isNullOk if true, return null for nulls or non-strings, else
58       * return an empty string
59       * @return if null or non-string, returns null as long as isNullOk is true,
60       * else return empty string.
61       */
62      static public String   getStr(Object   o, boolean isNullOk)
63      {
64          if (o == null)
65              return (isNullOk?null:"");
66  
67          if (! o.getClass().getName().equals("java.lang.String"))
68              return (isNullOk?null:"");
69  
70          return (String  )o;
71      }
72  
73  
74      /**
75       * Parse a string that contains a number.
76       *
77       * @return number parsed from string. 0, if invalid.
78       */
79      static public int parseInt(String   s)
80      {
81          int n = 0;
82          try {
83              n = Integer.parseInt(s);
84          } catch (Exception   e) {
85              // ignore
86          }
87          return n;
88      }
89  
90      /**
91       * Expand system property values enclosed in ${}.
92       *
93       * @param p properties object to expand property values
94       * @return properties object with expanded values
95       * @throws Exception if a system property value doesn't exist or the
96       * property value isn't enclosed properly in ${}
97       */
98      static public Properties   expandProperties(Properties   p)
99          throws Exception  
100     {
101         Properties   _p = new Properties  ();
102         Enumeration   keys = p.keys();
103         while (keys.hasMoreElements()) {
104             String   k = (String  )keys.nextElement();
105             String   v = (String  )p.getProperty(k);
106             _p.setProperty(k, StringUtils.expandPropertyValues(v));
107         }
108         return _p;
109     }
110 }
111
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