IsReference


1   /**
2    * $Id: IsReference.java 180 2007-03-15 12:56:38Z ssmc $
3    * Copyright 2002-2005 iDare Media, Inc. All rights reserved.
4    *
5    * Originally written by iDare Media, Inc. for release into the public domain. This
6    * library, source form and binary form, is free software; you can redistribute it and/or
7    * modify it under the terms of the GNU Lesser General Public License as published by the
8    * Free Software Foundation; either version 2 of the License, or (at your option) any later
9    * version.<p>
10   *
11   * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
12   * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
13   * See the GNU LGPL (GNU Lesser General Public License) for more details.<p>
14   *
15   * You should have received a copy of the GNU Lesser General Public License along with this
16   * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite
17   * 330, Boston, MA  02111-1307  USA. The LGPL can be found online at
18   * http://www.fsf.org/copyleft/lesser.html<p>
19   *
20   * This product has been influenced by several projects within the open-source community.
21   * The JWare developers wish to acknowledge the open-source community's support. For more
22   * information regarding the open-source products used within JWare, please visit the
23   * JWare website.
24   *----------------------------------------------------------------------------------------*
25   * WEBSITE- http://www.jware.info                           EMAIL- inquiries@jware.info
26   *----------------------------------------------------------------------------------------*
27   **/
28  
29  package com.idaremedia.antx.condition;
30  
31  import  org.apache.tools.ant.taskdefs.condition.Condition;
32  
33  import  com.idaremedia.antx.AssertableProjectComponent;
34  import  com.idaremedia.antx.FixtureExaminer;
35  import  com.idaremedia.antx.helpers.Tk;
36  
37  /**
38   * Simple Is-A-Reference condition check. Example usage:
39   * <pre>
40   *   &lt;isref name="the.err"/&gt;
41   *   &lt;isref name="module.classes" class="org.apache.tools.ant.types.DirSet"/&gt;
42   *   &lt;isref name="last.err" class="java.lang.Throwable" kindof="true"/&gt;
43   *</pre>
44   *
45   * @since    JWare/AntX 0.1
46   * @author   ssmc, &copy;2002-2005 <a HREF="http://www.jware.info">iDare&nbsp;Media,&nbsp;Inc.</a>
47   * @version  0.5
48   * @.safety  single
49   * @.group   api,infra
50   **/
51  
52  public class IsReference extends AssertableProjectComponent
53      implements Condition, URIable
54  {
55      /**
56       * Creates new IsReference condition; defaults
57       * to returning <i>true</i>.
58       **/
59      public IsReference()
60      {
61      }
62  
63  
64      /**
65       * Creates pre-defined IsReference condition.
66       * @param refid the refid against which condition checks
67       **/
68      public IsReference(String   refid)
69      {
70          setName(refid);
71      }
72  
73  
74      /**
75       * Sets reference name used by evaluation method.
76       * @param refId the reference's name (non-null)
77       **/
78      public void setName(String   refId)
79      {
80          m_refId = refId;
81      }
82  
83  
84      /**
85       * Returns reference name used by evaluation method.
86       **/
87      public final String   getName()
88      {
89          return m_refId;
90      }
91  
92  
93  
94      /**
95       * Sets this condition's reference name as part of 
96       * a value URI.
97       * @param fragment the value uri bits (non-null)
98       * @since JWare/AntX 0.5
99       */
100     public void xsetFromURI(String   fragment)
101     {
102         setName(fragment);
103     }
104 
105 
106 
107     /**
108      * Tells this condition that the reference shoudld <em>not</em>
109      * exist in order for condition to pass.
110      * @param noexist <i>true</i> if reference should not exist.
111      * @since JWare/AntX 0.5
112      **/
113     public void xsetNoExist(boolean noexist)
114     {
115         m_noexist = noexist;
116     }
117 
118 
119 
120     /**
121      * Returns current referenced this condition would use
122      * (will return <i>null</i> if never set or reference is
123      * undefined or reference is out-of-scope (defined in a
124      * target that has yet to execute).
125      **/
126     public Object   getReferencedObject()
127     {
128         require_(getProject()!=null,"getRefObj- in project");
129         String   refid= Tk.resolveString(getProject(),getName());
130         Object   ref = null;
131         if (refid!=null) {
132             ref = FixtureExaminer.trueReference(getProject(),refid);
133             if (ref==FixtureExaminer.IGNORED_REFERENCE) {
134                 ref = null;
135             }
136         }
137         return ref;
138     }
139 
140 
141     /**
142      * Sets whether reference must be of an exact class
143      * match or just a "kind-of" the class.
144      **/
145     public void setKindOf(boolean kindOf)
146     {
147         m_kindOf = kindOf;
148     }
149 
150 
151     /**
152      * Returns <i>true</i> if reference only has to be a
153      * "kind-of" class match and not an exact class match.
154      **/
155     public final boolean isKindOf()
156     {
157         return m_kindOf;
158     }
159 
160 
161     /**
162      * Sets the class the reference be an instance of.
163      * @since JWare/AntX 0.5
164      **/
165     public void setClassName(String   clazzname)
166     {
167         m_requiredClass = clazzname;
168     }
169 
170 
171     /**
172      * (Older)Synonym for {@linkplain #setClassName setClassName()}.
173      **/
174     public final void setClass(String   clazzname)
175     {
176         setClassName(clazzname);
177     }
178 
179 
180     /**
181      * Returns required instance-of class class name for
182      * this condition.
183      * Returns <i>null</i> if never set.
184      * @since JWare/AntX 0.5
185      **/
186     public final String   getClassName()
187     {
188         return m_requiredClass;
189     }
190 
191 
192 
193     /**
194      * Returns <i>true</i> if the condtion's property has not
195      * been explicitly set. This condition should behave reasonably 
196      * even if it was loaded by a classloader different from
197      * referenced object.
198      **/
199     public boolean eval()
200     {
201         verifyInProject_("eval");
202 
203         boolean result = false;
204         Object   object = getReferencedObject();
205 
206         if (object!=null) {
207             if (!m_noexist) {
208                 final String   classname = getClassName();
209                 if (classname!=null) {
210                     if (object==FixtureExaminer.PROBLEM_REFERENCE) {
211                         result= false;
212                     } else {
213                         result= object.getClass().getName().equals(classname);
214                         if (result==false && isKindOf()) {
215                             result = isCompatible(object,classname);
216                         }
217                     }
218                 } else {
219                     result= true;//=>just need to exist!
220                 }
221             }
222         } else if (m_noexist) {
223             result = true;
224         }
225 
226         return result;
227     }
228 
229 
230 
231     /**
232      * Tries to determine if object is assignment compatible with
233      * the named class. Has to work w/ names to avoid issues when condition
234      * and object loaded by different classloaders.
235      * @param object the referenced object
236      * @param classname class we're interested in.
237      * @return <i>true</i> if (sortof) compatible.
238      * @since JWare/AntX 0.5
239      **/
240     private boolean isCompatible(Object   object, String   classname)
241     {
242         boolean compatible = false;
243         ClassLoader   cl = object.getClass().getClassLoader();
244         if (cl!=null) {
245             try {
246                 Class   c = cl.loadClass(classname);
247                 compatible = c.isInstance(object);
248             } catch(ClassNotFoundException   cnfx) {
249                 /*burp*/
250             }
251         } else {
252             try {
253                 Class   c = Class.forName(classname);
254                 compatible = c.isInstance(object);
255             }catch(ClassNotFoundException   cnfx) {
256                 /*burp*/
257             }
258         }
259         return compatible;
260     }
261 
262 
263     private String    m_refId;//required
264     private boolean m_kindOf;//NB:=>*exact* match
265     private String    m_requiredClass;//NB:most flex to support diff classpaths
266     private boolean m_noexist;
267 }
268 
269 /* end-of-IsReference.java */
270
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