Bug 44241: 'activate' Steves <javaconstant> resource

WHATSNEW

@@ -13,6 +13,8 @@ Fixed bugs:
 
 Other changes:
 --------------
+ * Hidden <javaconstant> resource is published now. It reads the
+   value of a specified java constant.
 
 
 Changes from Ant 1.9.4 TO Ant 1.9.5

manual/Types/resources.html

@@ -43,6 +43,8 @@ explicit use beginning in <b>Ant 1.7</b>.
   <li><a href="#gzipresource">gzipresource</a> - a GZip compressed resource.</li>
   <li><a href="#javaresource">javaresource</a> - a resource loadable
         via a Java classloader.</li>
+  <li><a href="#javaconstant">javaconstant</a> - a constant in a class loadable
+        via a Java classloader.</li>
   <li><a href="#propertyresource">propertyresource</a> - an Ant property.</li>
   <li><a href="#string">string</a> - a text string.</li>
   <li><a href="#tarentry">tarentry</a> - an entry in a tar file.</li>
@@ -164,9 +166,49 @@ implementations are also usable as single-element
 where <b>&lt;classpath&gt;</b> is a <a
 href="../using.html#path">path-like structure</a>.</p>
 
+
+<h4><a name="javaconstant">javaconstant</a></h4>
+<p>Loads the value of a java constant. As a specialisation of 
+<a href="#javaresource">javaresource</a> all of its attributes and nested elements are
+supported. A constant must be specified as <tt>public static</tt> otherwise it could not be loaded.</p>
+
+<table border="1" cellpadding="2" cellspacing="0">
+  <tr>
+    <td valign="top"><b>Attribute</b></td>
+    <td valign="top"><b>Description</b></td>
+    <td align="center" valign="top"><b>Required</b></td>
+  </tr>
+  <tr>
+    <td valign="top">name</td>
+    <td valign="top">The name of the resource. Must be specified as full qualified
+      field name.
+    </td>
+    <td align="center" valign="top">Yes</td>
+  </tr>
+</table>
+<h5>Examples</h5>
+This loads the value of the constant <tt>VERSION</tt> of the <tt>org.acme.Main</tt> class
+into the <tt>version</tt>-property. The classpath for finding that class is provided via
+nested classpath element.
+<pre><code>&lt;loadresource property=&quot;version&quot;&gt;
+   &lt;javaconstant name=&quot;org.acme.Main.VERSION&quot;&gt;
+     &lt;classpath&gt;
+       &lt;pathelement location=&quot;${acme.lib.dir}&quot;/&gt;
+     &lt;/classpath&gt;
+   &lt;/javaconstant&gt;
+ &lt;/loadresource&gt;
+</code></pre>
+
+Create a new file <tt>c:/temp/org.apache.tools.ant.Main.DEFAULT_BUILD_FILENAME</tt> with the content
+of that constant (<tt>build.xml</tt>).
+<pre><code>&lt;copy todir=&quot;c:/temp&quot;&gt;
+  &lt;javaconstant name=&quot;org.apache.tools.ant.Main.DEFAULT_BUILD_FILENAME&quot;/&gt;
+&lt;/copy&gt;</code></pre>
+
+
 <h4><a name="zipentry">zipentry</a></h4>
 
-<p>Represents an entry in a ZIP archive.  The archive can be specified
+<p>Represents an entry in a ZIP archive. The archive can be specified
 using the archive attribute or a nested single-element resource
 collection.  <code>zipentry</code> only supports file system resources
 as nested elements.</p>

src/main/org/apache/tools/ant/types/defaults.properties

@@ -93,6 +93,7 @@ gzipresource=org.apache.tools.ant.types.resources.GZipResource
 bzip2resource=org.apache.tools.ant.types.resources.BZip2Resource
 javaresource=org.apache.tools.ant.types.resources.JavaResource
 multirootfileset=org.apache.tools.ant.types.resources.MultiRootFileSet
+javaconstant=org.apache.tools.ant.types.resources.JavaConstantResource
 
 #tokenizer implementations
 linetokenizer=org.apache.tools.ant.util.LineTokenizer

src/main/org/apache/tools/ant/types/resources/JavaConstantResource.java

@@ -39,6 +39,9 @@ public class JavaConstantResource extends AbstractClasspathResource {
     protected InputStream openInputStream(ClassLoader cl) throws IOException {
         Class<?> clazz;
         String constant = getName();
+        if (constant == null) {
+            throw new IOException("Attribute 'name' must be set.");
+        }
         int index1 = constant.lastIndexOf('.');
         if (index1 < 0) {
             throw new IOException("No class name in " + constant);

src/tests/antunit/types/resources/test.xml

@@ -400,4 +400,61 @@
     </au:assertTrue>
   </target>
 
+  <target name="testJavaConstant">
+    <property name="test.tmp.dir" value="${antunit.tmpdir}/testJavaConstant"/>
+    <mkdir dir="${test.tmp.dir}"/>
+    <echo file="${test.tmp.dir}/SomeClass.java">
+      public class SomeClass {
+          public  static final String CONSTANT   = "constant";
+          public         final String NOT_STATIC = "not-static";
+          private static final String PRIVATE    = "private";
+      }
+    </echo>
+    <javac srcdir="${test.tmp.dir}" destdir="${test.tmp.dir}"/>
+    <path id="tmp.cp">
+      <pathelement location="${test.tmp.dir}"/>
+    </path>
+
+    <loadresource property="actual">
+      <javaconstant name="org.apache.tools.ant.Main.DEFAULT_BUILD_FILENAME"/>
+    </loadresource>
+    <au:assertEquals message="could not read java constant" expected="build.xml" actual="${actual}" />
+
+    <!-- 
+    We can't test for special error messages using built-in tasks 
+    because they catch these messages 
+    -->
+    <au:expectfailure>
+      <loadresource property="p">
+        <javaconstant/>
+      </loadresource>
+    </au:expectfailure>
+    <au:expectfailure>
+      <loadresource property="p">
+        <javaconstant name="org.apache.tools.ant.MissingClass"/>
+      </loadresource>
+    </au:expectfailure>
+    <au:expectfailure>
+      <loadresource property="p">
+        <javaconstant name="SomeClass.CONSTANT2" classpathref="tmp.cp"/>
+      </loadresource>
+     </au:expectfailure>
+    <au:expectfailure>
+      <loadresource property="p">
+        <javaconstant name="SomeClass.PRIVATE">
+          <classpath>
+            <pathelement location="${test.tmp.dir}"/>
+          </classpath>
+        </javaconstant>
+      </loadresource>
+     </au:expectfailure>
+    <au:expectfailure>
+      <loadresource property="p">
+        <javaconstant name="SomeClass.NOT_STATIC"/>
+      </loadresource>
+     </au:expectfailure>
+    
+    <delete dir="${test.tmp.dir}"/>
+  </target>
+
 </project>