Implement idea from bug #35583 - Include a version class, org.apache.poi.Version, to allow easy introspection of the POI version

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@676221 13f79535-47bb-0310-9956-ffa450edef68

build.xml

@@ -369,6 +369,29 @@ under the License.
     </javac>
   </target>
 
+  <target name="compile-version" depends="init"
+        description="Compiles the version class">
+	<!-- Generate the .java file -->
+	<property name="version.java" value="${main.output.dir}/org/apache/poi/Version.java" />
+	<delete file="${version.java}" />
+	<copy 
+		file="src/resources/version/Version.java.template"
+		tofile="${version.java}">
+		<filterset>
+			<filter token="VERSION" value="${version.id}" />
+			<filter token="DSTAMP" value="${DSTAMP}" />
+		</filterset>
+	</copy>
+
+	<!-- Compile -->
+    <javac target="${jdk.version.class}" source="${jdk.version.source}"
+      failonerror="true" destdir="${main.output.dir}" debug="on" fork="yes"
+      srcdir="${main.output.dir}" />
+
+	<!-- Tidy up -->
+	<delete file="${version.java}" />
+  </target>
+
   <target name="test" depends="test-main,test-scratchpad,test-contrib"
     description="Tests main, contrib and scratchpad"/>
 
@@ -950,7 +973,7 @@ FORREST_HOME environment variable!</echo>
 		<!-- And that's it for maven -->
 	</target>
 
-    <target name="jar" depends="compile" description="Creates jar files for distribution">
+    <target name="jar" depends="compile,compile-version" description="Creates jar files for distribution">
         <jar destfile="${dist.dir}/${jar.name}-${version.id}-${DSTAMP}.jar">
 			<fileset dir="${main.output.dir}" />
 			<fileset dir="legal/" />

src/documentation/content/xdocs/changes.xml

@@ -37,6 +37,7 @@
 
 		<!-- Don't forget to update status.xml too! -->
         <release version="3.1.1-alpha1" date="2008-??-??">
+           <action dev="POI-DEVELOPERS" type="add">35583 - Include a version class, org.apache.poi.Version, to allow easy introspection of the POI version</action>
            <action dev="POI-DEVELOPERS" type="add">Allow the cloning of one HSSFCellStyle onto another, including cloning styles from one HSSFWorkbook onto another</action>
            <action dev="POI-DEVELOPERS" type="fix">45289 - finished support for special comparison operators in COUNTIF</action>
            <action dev="POI-DEVELOPERS" type="fix">45126 - Avoid generating multiple NamedRanges with the same name, which Excel dislikes</action>

src/documentation/content/xdocs/status.xml

@@ -34,6 +34,7 @@
 	<!-- Don't forget to update changes.xml too! -->
     <changes>
         <release version="3.1.1-alpha1" date="2008-??-??">
+           <action dev="POI-DEVELOPERS" type="add">35583 - Include a version class, org.apache.poi.Version, to allow easy introspection of the POI version</action>
            <action dev="POI-DEVELOPERS" type="add">Allow the cloning of one HSSFCellStyle onto another, including cloning styles from one HSSFWorkbook onto another</action>
            <action dev="POI-DEVELOPERS" type="fix">45289 - finished support for special comparison operators in COUNTIF</action>
            <action dev="POI-DEVELOPERS" type="fix">45126 - Avoid generating multiple NamedRanges with the same name, which Excel dislikes</action>

src/resources/version/Version.java.template

@@ -0,0 +1,69 @@
+/* ====================================================================
+   Licensed to the Apache Software Foundation (ASF) under one or more
+   contributor license agreements.  See the NOTICE file distributed with
+   this work for additional information regarding copyright ownership.
+   The ASF licenses this file to You under the Apache License, Version 2.0
+   (the "License"); you may not use this file except in compliance with
+   the License.  You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+==================================================================== */
+
+package org.apache.poi;
+
+/**
+ * Administrative class to keep track of the version number of the 
+ *  POI release.
+ *
+ * This class implements the upcoming standard of having 
+ *  org.apache.project-name.Version.getVersion() be a standard 
+ *  way to get version information.
+ */
+public class Version {
+	private static final String VERSION_STRING = "@VERSION@";
+	private static final String RELEASE_DATE = "@DSTAMP@";
+
+	/**
+	 * Return the basic version string, of the form
+	 *  nn.nn(.nn)
+	 */
+	public static String getVersion() {
+		return VERSION_STRING;
+	}
+
+	/**
+	 * Return the date of the release / build
+	 */
+	public static String getReleaseDate() {
+		return RELEASE_DATE;
+	}
+
+	/**
+	 * Name of product: POI
+	 */
+	public static String getProduct() {
+		return "POI";
+	}
+	/**
+	 * Implementation Language: Java
+	 */
+	public static String getImplementationLanguage() {
+		return "Java";
+	}
+
+	/**
+	 * Prints the version to the command line
+	 */
+	public static void main(String[] args) {
+		System.out.println(
+			"Apache " + getProduct() + " " +
+			getVersion() + " (" + getReleaseDate() + ")"
+		);
+	}
+}