Bug 51548 - added the handler in the antlib.xml. Add more substantial javadocs. Need to work on an example before I close the ticket.

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1151847 13f79535-47bb-0310-9956-ffa450edef68

src/excelant/java/org/apache/poi/ss/excelant/ExcelAntHandlerTask.java

@@ -24,6 +24,21 @@ import org.apache.tools.ant.Task;
 
 /**
  * This is the class that backs the <handler> tag in the Ant task.
+ * <p>
+ * Its purpose is to provide a way to manipulate a workbook in the course
+ * of an ExcelAnt task.  The idea being to model a way for test writers to
+ * simulate the behaviors of the workbook. 
+ * <p>
+ * Suppose, for example, you have a workbook that has a worksheet that
+ * reacts to values entered or selected by the user.  It's possible in
+ * Excel to change other cells based on this but this isn't easily possible
+ * in POI.  In ExcelAnt we handle this using the Handler, which is a Java
+ * class you write to manipulate the workbook. 
+ * <p>
+ * In order to use this tag you must write a class that implements the 
+ * <code>IExcelAntWorkbookHandler</code> interface.  After writing the
+ * class you should package it and it's dependencies into a jar file to 
+ * add as library in your Ant build file.
  * 
  * @author Jon Svede ( jon [at] loquatic [dot] com )
  * @author Brian Bush ( brian [dot] bush [at] nrel [dot] gov )

src/excelant/resources/org/apache/poi/ss/excelant/antlib.xml

@@ -26,5 +26,6 @@ under the License.
     <typedef name="setFormula" classname="org.apache.poi.ss.excelant.ExcelAntSetFormulaCell"/>
     <typedef name="evaluate" classname="org.apache.poi.ss.excelant.ExcelAntEvaluateCell"/>
     <typedef name="udf" classname="org.apache.poi.ss.excelant.ExcelAntUserDefinedFunction"/>
+    <typedef name="handler" classname="org.apache.poi.ss.excelant.ExcelAntHandlerTask"/>
 
 </antlib>