As Simple as a Java Static Method"

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{{ZSS EE}}
  
 
ZK Spreadsheet allows developers to write their own custom formula functions. One way of implementing them is as a Java static method & declaring using xel-directive and another one is to implement it as EL function and register it in a TLD. Here we describe the first method.
 
ZK Spreadsheet allows developers to write their own custom formula functions. One way of implementing them is as a Java static method & declaring using xel-directive and another one is to implement it as EL function and register it in a TLD. Here we describe the first method.
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===Implement formula function===
 
===Implement formula function===
 
Define your custom formula function as a normal Java static method. For example here is a static method to convert USD to TWD.
 
Define your custom formula function as a normal Java static method. For example here is a static method to convert USD to TWD.
<source lang="java" high="3">
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<source lang="java" highlight="3">
 
public class CurrencyFns {
 
public class CurrencyFns {
  
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===ZUML===
 
===ZUML===
To be able to use above defined toTWD static method as a custom ZK Spreadsheet formula fuction declare it in your ZUL page using xel-method directive[http://books.zkoss.org/wiki/ZK_ZUML_Reference/The_ZK_User_Interface_Markup_Language/Processing_Instructions/The_xel-method_Directive] along with ZK Spreadsheet component as shown below
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To be able to use above defined toTWD static method as a custom ZK Spreadsheet formula fuction declare it in your ZUL page using [[ZK_ZUML_Reference/The_ZK_User_Interface_Markup_Language/Processing_Instructions/The_xel-method_Directive|the xel-method directive]] along with ZK Spreadsheet component as shown below
<source lang="xml" high="2,3,4">
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<source lang="xml" highlight="2,3,4">
 
<?page title="ZSS" contentType="text/html;charset=UTF-8"?>
 
<?page title="ZSS" contentType="text/html;charset=UTF-8"?>
 
<?xel-method prefix="zss" name="toTWD"
 
<?xel-method prefix="zss" name="toTWD"
     class="org.zkoss.zss.example.CurrencyFns"   
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     class="org.zkoss.zssessentials.functions.CurrencyFns"   
 
     signature="double toTWD(double,double)"?>
 
     signature="double toTWD(double,double)"?>
 
<zk>
 
<zk>
<window title="ZSS User Defined Functions" border="normal"
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<window title="ZSS User Defined Functions as Java static method" border="normal"
 
width="100%" height="100%">
 
width="100%" height="100%">
 
<spreadsheet width="800px" height="800px"
 
<spreadsheet width="800px" height="800px"
src="/test2/xls/elfn.xlsx" maxrows="20" maxcolumns="10">
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src="/WEB-INF/excel/functions/customfunctions.xlsx" maxrows="20" maxcolumns="10">
 
</spreadsheet>
 
</spreadsheet>
 
</window>
 
</window>
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=toTWD(A1,B1)
 
=toTWD(A1,B1)
 
</source>
 
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View complete source of ZUML [http://code.google.com/p/zkbooks/source/browse/trunk/zssessentials/examples/WebContent/functions/javafunction.zul javafunction.zul]
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View complete source of function implementation class [http://code.google.com/p/zkbooks/source/browse/trunk/zssessentials/examples/src/org/zkoss/zssessentials/functions/CurrencyFns.java CurrencyFns.java]
  
 
=Version History=
 
=Version History=

Latest revision as of 12:56, 19 January 2022




Stop.png This article is out of date, please refer to http://books.zkoss.org/wiki/ZK_Spreadsheet_Essentials for more up to date information.


Available in ZK Spreadsheet EE only

ZK Spreadsheet allows developers to write their own custom formula functions. One way of implementing them is as a Java static method & declaring using xel-directive and another one is to implement it as EL function and register it in a TLD. Here we describe the first method.

Purpose

Implement a custom formula function as a Java static method.

Implement formula function

Define your custom formula function as a normal Java static method. For example here is a static method to convert USD to TWD.

public class CurrencyFns {

	public static double toTWD(double usdNum, double twdRate) {
		return usdNum * twdRate;
	}
}

ZUML

To be able to use above defined toTWD static method as a custom ZK Spreadsheet formula fuction declare it in your ZUL page using the xel-method directive along with ZK Spreadsheet component as shown below

<?page title="ZSS" contentType="text/html;charset=UTF-8"?>
<?xel-method prefix="zss" name="toTWD"
    class="org.zkoss.zssessentials.functions.CurrencyFns"   
    signature="double toTWD(double,double)"?>
<zk>
	<window title="ZSS User Defined Functions as Java static method" border="normal"
		width="100%" height="100%">
		<spreadsheet width="800px" height="800px"
			src="/WEB-INF/excel/functions/customfunctions.xlsx" maxrows="20" maxcolumns="10">
		</spreadsheet>
	</window>
</zk>

Note that xel-method prefix attribute value must be set to "zss" for ZK Spreadsheet to invoke custom implementation for such custom formula function.

Using custom formula function in ZK Spreadsheet

Once defined and declared above custom formula function can be used just like any other built-in functions of Excel. Note that when entered in MS Excel it will result in #NAME? being displayed but when entered in ZK Spreadsheet it will we evaluated by invoking custom implementation declared through xel-method directive.

=toTWD(A1,B1)

View complete source of ZUML javafunction.zul

View complete source of function implementation class CurrencyFns.java

Version History

Last Update : 2022/01/19


Version Date Content
     


All source code listed in this book is at Github.


Last Update : 2022/01/19

Copyright © Potix Corporation. This article is licensed under GNU Free Documentation License.